NCHRP 9-30A CALIBRATION OF RUTTING MODELS …onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP09-30A_NR...NCHRP 9-30A September 2010 Appendix J Evaluation of Test Sections Used for Calibration

NCHRP 9-30A

CALIBRATION OF RUTTING MODELS FOR HMA STRUCTURAL AND MIXTURE DESIGN

APPENDIX J FORENSIC INVESTIGATION AND EVALUATION OF

TEST SECTIONS USED FOR CALIBRATION

Prepared for: National Cooperative Highway Research Program

Transportation Research Board National Research Council of National Academies

Washington, DC

Prepared by: Mr. Harold L. Von Quintus, P.E., ARA (Principal Investigator)

Mr. Jagannath Mallela, ARA (Project Manager) Dr. Ramond Bonaquist, P.E., AAT (Co-Principal Investigator)

Dr. Charles W. Schwartz, P.E., UMd (Co-Principal Investigator) Mr. Regis L. Carvalho, UMd

Submitted by: Applied Research Associates, Inc. 2003 North Mays Street, Suite 105

Round Rock, TX 78664 (512) 218-5088

September 2010

NCHRP 9-30A September 2010 Appendix J─Evaluation of Test Sections Used for Calibration

Applied Research Associates, Inc. University of Maryland Advanced Asphalt Technologies, LCC

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ACKNOWLEDGEMENT OF SPONSORSHIP This work was sponsored by the American Association of State Highway and Transportation Officials, in cooperation with the Federal Highway Administration, and was conducted through the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies.

DISCLAIMER The opinions and conclusions expressed or implied in the report are those of the research agency. They are not necessarily those of the Transportation Research Board, the National Research Council, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, or the individual states participating in the National Cooperative Highway Research Program.



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TABLE OF CONTENTS Page No. List of Tables ................................................................................................................ J-iv List of Figures ................................................................................................................. J-v Acknowledgements ................................................................................................................ J-vi Abstract ............................................................................................................... J-vii J-1 INTRODUCTION......................................................................................................... J-1 J-1.1 Background ......................................................................................................... J-1 J-1.2 Rut Depth Transfer Functions ............................................................................. J-1 J-2 ALABAMA LTPP SPS-6 PROJECT .......................................................................... J-3 J-2.1 Construction History ........................................................................................... J-3 J-2.2 Pavement Cross Section ...................................................................................... J-3 J-2.3 Material Properties Reported during Construction ............................................. J-4 J-2.4 HMA Mixture Characterization Tests for Rutting Predictions ........................... J-5 J-2.5 Analysis of Measured Rut Depths ...................................................................... J-5 J-2.6 Rut Depth Predictions Using the Global Transfer Function Coefficients .......... J-7 J-2.7 Field-Derived Coefficients of the Transfer Functions ........................................ J-8 J-2.8 NCHRP 1-40B Mixture Adjustment Factors .................................................... J-15 J-2.9 Average Rut Depths Extracted from LTPP Database ....................................... J-16 J-2.10 MEPDG Input Summary: Alabama SPS-6 Test Section Example ................... J-17 J-3 ARIZONA LTPP SPS-5 PROJECT .......................................................................... J-23 J-3.1 Construction History ......................................................................................... J-23 J-3.2 Pavement Cross Section .................................................................................... J-23 J-3.3 Material Properties Reported during Construction ........................................... J-24 J-3.4 Analysis of Measured Rut Depths .................................................................... J-25 J-3.5 Forensic Investigation of SPS-5 Project ........................................................... J-27 J-3.6 HMA Mixture Characterization Tests for Rutting Predictions ......................... J-34 J-3.7 Rut Depth Predictions Using the Global Transfer Function Coefficients ........ J-32 J-3.8 Field-Derived Coefficients of the Transfer Functions ...................................... J-36 J-3.9 NCHRP 1-40B Mixture Adjustment Factors .................................................... J-39 J-3.10 Average Rut Depth Measurements Extracted from LTPP Database ................ J-40 J-3.11 MEPDG Input Summary: Arizona SPS-5 Test Section Example .................... J-42 J-4 COLORADO LTPP SPS-5 PROJECT ..................................................................... J-50 J-4.1 Construction History ......................................................................................... J-50 J-4.2 Pavement Cross Section .................................................................................... J-50 J-4.3 Material Properties Reported during Construction ........................................... J-51 J-4.4 Analysis of Measured Rut Depths .................................................................... J-52 J-4.5 HMA Mixture Characterization Tests for Rutting Predictions ......................... J-55 J-4.6 Rut Depth Predictions Using the Global Transfer Function Coefficients ........ J-55 J-4.7 Field-Derived Coefficients of the Transfer Functions ...................................... J-57 J-4.8 NCHRP 1-40B Mixture Adjustment Factors .................................................... J-61



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J-4.9 Average Rut Depths Extracted from LTPP Database ....................................... J-62 J-5 MISSISSIPPI LTPP SPS-5 PROJECT ..................................................................... J-63 J-5.1 Construction History ......................................................................................... J-64 J-5.2 Pavement Cross Section .................................................................................... J-64 J-5.3 Material Properties Reported during Construction ........................................... J-67 J-5.4 HMA Mixture Characterization Tests for Rutting Predictions ......................... J-71 J-5.5 Analysis of Measured Rut Depths .................................................................... J-71 J-5.6 Forensic Investigation of Mississippi SPS-5 Project ........................................ J-73 J-5.7 Rut Depth Predictions Using the Global Transfer Function Coefficients ........ J-73 J-5.8 Field-Derived Coefficients of the Transfer Functions ...................................... J-76 J-5.9 NCHRP 1-40B Mixture Adjustment Factors .................................................... J-79 J-5.10 Average Rut Depths Extracted from LTPP Database ....................................... J-80 J-6 MISSOURI LTPP SPS-5 PROJECT ........................................................................ J-81 J-6.1 Construction History ......................................................................................... J-81 J-6.2 Pavement Cross Section .................................................................................... J-81 J-6.3 Material Properties Reported during Construction ........................................... J-82 J-6.4 Analysis of Measured Rut Depths .................................................................... J-85 J-6.5 Forensic Investigation of Missouri SPS-5 Project ............................................ J-86 J-6.6 HMA Mixture Characterization Tests for Rutting Predictions ......................... J-87 J-6.7 Rut Depth Predictions Using the Global Transfer Function Coefficients ........ J-88 J-6.8 Field-Derived Coefficients of the Transfer Functions ...................................... J-88 J-6.9 NCHRP 1-40B Mixture Adjustment Factors .................................................... J-93 J-6.10 Average Rut Depths Extracted from LTPP Database ....................................... J-94 J-6.11 MEPDG Input Summary: Missouri SPS-5 Test Section Example .................. J-95 J-7 MONTANA LTPP SPS-5 PROJECT ..................................................................... J-101 J-7.1 Construction History ....................................................................................... J-101 J-7.2 Pavement Cross Section .................................................................................. J-101 J-7.3 Material Properties Reported during Construction ......................................... J-102 J-7.4 Analysis of Measured Rut Depths .................................................................. J-104 J-7.5 Forensic Investigation of Montana SPS-5 Project .......................................... J-107 J-7.6 HMA Mixture Characterization Tests for Rutting Predictions ....................... J-107 J-7.7 Rut Depth Predictions Using the Global Transfer Function Coefficients ...... J-107 J-7.8 Field-Derived Coefficients of the Transfer Functions .................................... J-109 J-7.9 NCHRP 1-40B Mixture Adjustment Factors .................................................. J-113 J-7.10 Average Rut Depths Extracted from LTPP Database ..................................... J-114 J-7.11 MEPDG Input Summary: Montana SPS-5 Test Section Example ................ J-116 J-8 TEXAS LTPP SPS-5 PROJECT ............................................................................. J-122 J-8.1 Construction History ....................................................................................... J-122 J-8.2 Pavement Cross Section .................................................................................. J-122 J-8.3 Material Properties Reported during Construction ......................................... J-123 J-8.4 Analysis of Measured Rut Depths .................................................................. J-125 J-8.5 Forensic Investigation of Texas SPS-5 Project ............................................... J-127



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J-8.6 HMA Mixture Characterization Tests for Rutting Predictions ....................... J-135 J-8.7 Rut Depth Predictions Using the Global Transfer Function Coefficients ...... J-135 J-8.8 Field-Derived Coefficients of the Transfer Functions .................................... J-140 J-8.9 NCHRP 1-40B Mixture Adjustment Factors .................................................. J-143 J-8.10 Average Rut Depths Extracted from LTPP Database ..................................... J-144 J-8.11 MEPDG Input Summary: Texas SPS-5 Test Section Example ..................... J-145 J-9 WISCONSIN LTPP SPS-1 AND SPS-9 PROJECTS ............................................ J-153 J-9.1 Construction History ....................................................................................... J-153 J-9.2 Pavement Cross Section/Structure .................................................................. J-153 J-9.3 Material Properties Reported during Construction ......................................... J-154 J-9.4 Analysis of Measured Rut Depths .................................................................. J-155 J-9.5 Forensic Investigation of SPS-1 Project ......................................................... J-156 J-9.6 Deflection Profiles .......................................................................................... J-164 J-9.7 HMA Mixture Characterization Tests for Rutting Predictions ....................... J-166 J-9.8 Rut Depth Predictions Using the Global Transfer Function Coefficients ...... J-168 J-9.9 Field-Derived Plastic Deformation Coefficients ............................................ J-177 J-9.10 NCHRP 1-40B Mixture Adjustment Factors .................................................. J-180 J-9.11 Average Rut Depths Extracted from LTPP Database ..................................... J-181 J-9.12 MEPDG Input Summary: Wisconsin SPS-1 Test Section Example ............. J-182



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LIST OF TABLES Table No. Title of Table Page No. AL-1 Summary of Average Layer Thickness from LTPP Database ............................ J-3 AL-2 Bias and Standard Error of the Estimate for the Rut Depth Transfer

Functions ............................................................................................................. J-8 AL-3 Field-Derived Slope and Intercept .................................................................... J-12 AL-4 Bias and Standard Error of the Estimate for the Rut Depth Transfer

Functions Using the Field-Derived Values ....................................................... J-12 AZ-1 Summary of Average Layer Thickness from LTPP Database .......................... J-24 AZ-2 Field-Derived Slope and Intercept .................................................................... J-36 CO-1 Summary of Average Layer Thickness from LTPP Database .......................... J-51 CO-2 Field-Derived Slope and Intercept .................................................................... J-60 MS-1 Summary of Average Layer Thickness from LTPP Database .......................... J-65 MS-2 Field-Derived Slope and Intercept .................................................................... J-76 MO-1 Summary of Average Layer Thickness from LTPP Database .......................... J-81 MO-2 Field-Derived Slope and Intercept .................................................................... J-92 MT-1 Summary of Average Layer Thickness from LTPP Database ........................ J-101 MT-2 Field-Derived Slope and Intercept .................................................................. J-112 TX-1 Summary of Average Layer Thickness from LTPP Database ........................ J-122 TX-2 Field-Derived Slope and Intercept .................................................................. J-142 WS-1 Summary of Average Layer Thickness from LTPP Database ........................ J-153 WS-2 Field-Derived Slope and Intercept .................................................................. J-177



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LIST OF FIGURES Figure No. Figure Caption Page No. AL-1 Dynamic Modulus Values Measured on the HMA Overlay Mixture with

the Polymer Modified Asphalt ........................................................................... J-6 AL-2 Rut Depths Measured over Time for each SPS-6 Test Section with an

HMA Overlay ..................................................................................................... J-6 AL-3 Effect of HMA Overlay Thickness on Maximum Rut Depth ............................. J-7 AL-4 Intact PCC Slab Sections: Predicted versus Measured Rut Depths Using

MEPDG Version 9-30A and the Global Plastic Deformation Values ................ J-9 AL-5 Crack and Seat Sections: Predicted versus Measured Rut Depths Using

MEPDG Version 9-30A and the Global Plastic Deformation Values .............. J-10 AL-6 Rubblized Test Section: Predicted versus Measured Rut Depths Using

MEPDG Version 9-30A and the Global Plastic Deformation Values .............. J-11 AL-7 Examples of Predicted versus Measured Rut Depths for the Test Sections

with Fractured PCC Slabs Using MEPDG Version 9-30A and the Field-Derived Values (see Table AL-3) ..................................................................... J-13

AL-8 Examples of Predicted versus Measured Rut Depths for the Intact PCC Test Sections Using MEPDG Version 9-30A and the Field-Derived Values (see Table AL-3) ................................................................................... J-14

AZ-1 Average Maximum Rut Depths Measured with Time ...................................... J-24 AZ-2 Rut Depths Measured over Time for each Test Section ................................... J-26 AZ-3 Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth ............................................................................................................... J-26 AZ-4 Trench Excavated within Section 04-0509 (RAP Mixture) .............................. J-28 AZ-5 Trench Excavated within Section 04-0506 (Virgin Mixture) ........................... J-28 AZ-6 Photographs of Cores Recovered from Section 04-0506 (Virgin Mixture) ...... J-29 AZ-7 Photographs of Cores Recovered from Section 04-0509 (RAP Mixture) ........ J-30 AZ-8 Horizontal Depth Profiles for Section 04-0506 Virgin HMA Mixture ............. J-31 AZ-9 Horizontal Depth Profiles for Section -5-0509 RAP Overlay .......................... J-31 AZ-10 Layer or Lift Thickness Measurements taken along the Cut Face of the

Trench Excavated for Section 0509 .................................................................. J-32 AZ-11 Layer or Lift Thickness Measurements taken along the Cut Face of the

Trench Excavated for Section 0506 .................................................................. J-32 AZ-12 Differential Layer Thickness Measured along the Cut Face of the Trench

for Section 0509 ................................................................................................ J-33 AZ-13 Differential Layer Thickness Measured along the Cut Face of the Trench

for Section 0506 ................................................................................................ J-33 AZ-14 Dynamic Modulus Values Measured on the HMA Mixture without RAP ....... J-34 AL-15 Comparison of the Predicted and Measured Rut Depths using the Global

Plastic Deformation Coefficients for the Different Rut Depth Transfer Functions for Sections 0502 (RAP Mixtures) ................................................... J-35



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AZ-16 Comparison of the Predicted and Measured Rut Depths using the Global Plastic Deformation Coefficients for the Different Rut Depth Transfer Functions for Sections 0505 (Virgin Mixtures) ................................................ J-35

AZ-17 Comparison of the Predicted and Measured Rut Depths using the Global Coefficients for each Transfer Function for the Test Sections with RAP Mixtures ............................................................................................................ J-37

AZ-18 Comparison of the Predicted and Measured Rut Depths using the Global Coefficients for each Transfer Function for the Test Sections with Virgin Mixtures (without RAP) ................................................................................... J-38

CO-1 Rut Depths Measured over Time for the SPS-5 Core Test Sections with RAP Mixtures ................................................................................................... J-53

CO-2 Rut Depths Measured over Time for the SPS-5 Core Test Sections without RAP Mixtures (Virgin Mixtures) ...................................................................... J-53

CO-3 Effect of HMA Overlay Thickness on Maximum Rut Depth ........................... J-54 CO-4 Dynamic Modulus Values Measured on the HMA Mixture without RAP ....... J-55 CO-5 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and

the Global Plastic Deformation Coefficients for each Transfer Function for SPS-5 Sections 0502 and 0508 (RAP Mixtures) .............................................. J-56

CO-6 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and the Global Plastic Deformation Coefficients for each Transfer Function for SPS-5 Sections 0505 and 0506 (Virgin Mixtures) ............................................ J-57

CO-7 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0508 (RAP Mixtures) ........................................................................................ J-58

CO-8 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0505 and 0507 (Virgin Mixtures) ..................................................................................... J-59

MS-1 Normalized Truck Volume Distribution Factors for the Mississippi SPS-5 Project ............................................................................................................... J-63

MS-2 Rut Depth Time-Series Data from LTPP Showing the Rutting Prior to Overlay .............................................................................................................. J-64

MS-3 Resilient Modulus Test Extracted from the LTPP Database ............................ J-66 MS-4 Comparison of Resilient Modulus to Elastic Layered Modulus Back-

Calculated with EVERCALC for the Subgrade ................................................ J-66 MS-5 Comparison of Dynamic Modulus Values Predicted with the MEPDG to

the Back-Calculated Elastic Layered Modulus Values ..................................... J-67 MS-6 Damage Estimate from FWD Measurements for the Overlay and Existing

HMA Layers ..................................................................................................... J-68 MS-7 Dynamic Modulus Values Measured on the HMA Overlay ............................. J-72 MS-8 Rut Depth Measured over Time for the SPS-5 Test Sections ........................... J-72 MS-9 Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth ............................................................................................................... J-73 MS-10 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and

the Global Plastic Deformation Coefficients for each Transfer Function for SPS-5 Sections 0504 and 0505 (Mixtures without RAP) ................................. J-74



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MS-11 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and the Global Plastic Deformation Coefficients for each Transfer Function for SPS-5 Sections 0502 and 0503 (Mixtures with RAP) ...................................... J-75

MS-12 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0504 and 0505 (Mixtures without RAP) .......................................................................... J-77

MS-13 Predicted versus Measured Rut Depths Using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0503 (Mixtures with RAP) ............................................................................... J-78

MO-1 Rut Depth Time-Series Data from LTPP Showing the Rutting Prior to and after Overlay Placement .................................................................................... J-82

MO-2 Rut Depths Measured Over Time for the SPS-5 Test Sections ........................ J-86 MO-3 Effect of Overlay Thickness and Mixture Type on Maximum Rut Depth ....... J-86 MO-4 Dynamic Modulus Values Measured on the HMA Mixture without RAP ....... J-87 MO-5 Dynamic Modulus Values Measured on the HMA Mixture with RAP ............ J-88 MO-6 Comparison of the Predicted and Measured Rut Depths Using the Global

Coefficients for each Transfer Function for SPS-5 Sections 0502 and 0508 with RAP Mixtures ........................................................................................... J-89

MO-7 Comparison of the Predicted and Measured Rut Depths Using the Global Coefficients for each Transfer Function for SPS-5 Sections 0505 and 0507 without RAP Mixtures ...................................................................................... J-90

MO-8 Predicted versus Measured Rut Depths Using the MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0504 and 0505 (Mixtures without RAP) .................................................................... J-91

MO-9 Predicted versus Measured Rut Depths Using the MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0508 (Mixtures with RAP) ......................................................................... J-92

MT-1 Rut Depth Time-Series Data from LTPP Showing the Rutting Prior to Overlay and After the Second Rehabilitation Strategy: Missouri SPS-5 Project ............................................................................................................. J-102

MT-2 Rut Depths Measured Over Time for each of the Core SPS-5 Test Sections from Prior to Overlay Placement to the Second Rehabilitation Activity ....... J-105

MT-3 Rut Depths Measured along the Supplemental Test Sections in Comparison to Selected Core Sections of the SPS-5 Project ......................... J-106

MT-4 Effect of Overlay Thickness and Mixture Type on Maximum Rut Depth ..... J-106 MT-5 Dynamic Modulus Values Measured on the HMA Mixture without RAP ..... J-107 MT-6 Comparison of the Predicted and Measured Rut Depths Using the Global

Coefficients for each Transfer Function for SPS-5 Sections 0502 (No Milling) and 0508 (Milled Surface); Mixtures with RAP .............................. J-108

MT-7 Comparison of the Predicted and Measured Rut Depths Using the Global Coefficients for each Transfer Function for SPS-5 Sections 0505 (No Milling) and 0507 (Milled Surface); Mixtures without RAP ......................... J-109

MT-8 Predicted versus Measured Rut Depths Using the MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0505 (No Milling) and 0507 (Milled Surface); Mixtures without RAP .................. J-110



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MT-9 Predicted versus Measured Rut Depths Using the MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 (No Milling) and 0508 (Milled Surface); Mixtures with RAP ....................... J-111

TX-1 Average Maximum Rut Depths Measured with Time for Section 48_A0507 (Mixtures without RAP) and A0508 (Mixtures without RAP) ..... J-126

TX-2 Rut Depths Measured Over Time for each Test Section ............................... J-126 TX-3 Effect of Overlay Thickness and Mixture Type on Maximum Rut Depth ..... J-127 TX-4 Trench Excavated within Section 48-0507 (Virgin Mixture) ......................... J-128 TX-5 Trench Excavated within Section 48-0508 (RAP Mixture) ............................ J-128 TX-6 Photos of Cores Recovered from Section 48-A0507 (Virgin Mixture) .......... J-129 TX-7 Photos of Cores Recovered from Section 48-A0508 (RAP Mixture)............. J-130 TX-8 Photo Showing the HMA Stripping that has Occurred in Localized Areas

within the Existing HMA Layer ..................................................................... J-131 TX-9 Photos Showing the Layer Thickness Measurements within the Trench ....... J-131 TX-10 Section 48-A507 Virgin HMA Overlay .......................................................... J-132 TX-11 Section 48-A508 RAP Overlay ....................................................................... J-132 TX-12 Layer or Lift Thickness Measurements Taken along the Cut Face of the

Trench Excavated for Section 48-A507 with the Virgin Mixture .................. J-133 TX-13 Layer or Lift Thickness Measurements Taken along the Cut Face of the

Trench Excavated for Section 48-A508 with the RAP Mixture ..................... J-133 TX-14 Differential Layer Thickness Measured along the Cut Face of the Trench

for Section 48-A507 with the Virgin Mixture ................................................ J-134 TX-15 Differential Layer Thickness Measured along the Cut Face of the Trench

for Section 48-A508 with the RAP Mixture ................................................... J-134 TX-16 Comparison of the Predicted and Measured Rut Depths Using the Global

Coefficients for each Transfer Function for the Core Test Sections in the Texas SPS-5 Project ........................................................................................ J-136

TX-17 Comparison of the Predicted and Measured Rut Depths for the Global Calibration Values for the MEPDG, Asphalt Institute, and Verstraeten Transfer Functions .......................................................................................... J-137

TX-18 Comparison of the Predicted and Measured Rut Depths for the Global Calibration Values for the WesTrack Transfer Function and the MEPDG using the NCHRP 1-40B Mix Adjustment Factors......................................... J-138

TX-19 Comparison of the Predicted and Measured Rut Depths and Residual Error Using the MEPDG Global Calibration Values for the SPS-5 Project ............ J-139

TX-20 Comparison of the Predicted and Measured Rut Depths and Residual Error Using the NCHRP 1-40B Mix Adjustment Values for the SPS-5 Sections ... J-140

TX-21 Predicted versus Measured Rut Depths Using the MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0505 and 0507; Mixtures without RAP ................................................................... J-141

TX-22 Predicted versus Measured Rut Depths Using the MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0508; Mixtures with RAP ........................................................................ J-142

WS-1 Maximum Rut Depth Related to Total HMA Thickness of Dense-Graded Mixtures .......................................................................................................... J-156



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WS-2 Maximum Rut Depth Related to Total HMA Thickness of Dense-Graded Mixtures Stratified by Test Sections with and without an ATB Layer........... J-156

WS-3 Average Maximum Rut Depths Measured over Time for Sections 55-0113 and 55-0116 .................................................................................................... J-157

WS-4 Rut Depths Measured over Time for the Wisconsin SPS-1 Test Sections ..... J-157 WS-5 Rut Depths Measured over Time for the Wisconsin SPS-9 Test Sections;

includes PMA Mixtures, No ATB and No PATB Layers .............................. J-158 WS-6 Photos of the Trenching Operations for Section 55-0113 .............................. J-159 WS-7 Trench Operations in Section SPS-1 55-0116 near Hatley, Wisconsin .......... J-160 WS-8 Cross Section of the Trench and the Open Trench; Section 55-0116 ............. J-160 WS-9 Layer or Lift Thickness Measurements taken along the Cut Face of the

Trench Excavated for Section 0116 for the HMA Layers .............................. J-162 WS-10 Layer or Lift Thickness Measurements taken along the Cut Face of the

Trench Excavation for Section 0116 for all Layers ........................................ J-162 WS-11 Layer or Lift Thickness Measurements taken along the Cut Face of the

Trench Excavated for Section 0116 for the HMA Binder Layer .................... J-163 WS-12 Layer or Lift Thickness Measurements taken along the Cut Face of the

Trench Excavated for Section 0116 for the ATB Layer ................................. J-163 WS-13 Differential Layer Thickness Measured along the Cut Face of the Trench

for Section 0116 .............................................................................................. J-164 WS-14 Deflections Measured over Time for the Two Wisconsin SPS-1 Sections

that were Trenched (55-0113 and 55-0116) .................................................... J-165 WS-15 Deflections Measured over Time Comparing Wisconsin SPS-1 Section

0114 and Two SPS-9 Sections (C901 and C960) ........................................... J-166 WS-16 Dynamic Modulus Values Measured on the Mixtures for the different

HMA Layers for the Wisconsin SPS-1 Project............................................... J-167 WS-17 Comparison of Measured and Predicted Rut Depths Using the Global

Calibration Values for the MEPDG Rut Depth Transfer Function ................. J-168 WS-18 Comparison of the Measured Rut Depths over Time for the Wisconsin

SPS-1 Test Sections with and without an ATB Layer .................................... J-169 WS-19 Comparison of Predicted and Measured Rut Depths for the Wisconsin

SPS-9 Test Sections ........................................................................................ J-170 WS-20 Comparison of Predicted and Measured Rut Depths and Residual Error

Using the MEPDG Global Calibration Values for the SPS-1 and SPS-9 Projects ............................................................................................................ J-171

WS-21 Gradation for the Wisconsin SPS-1 Wearing Surface and Binder Layer ....... J-173 WS-22 Comparison of the Predicted and Measured Rut Depths and Residual Error

Using the NCHRP 1-40B Mix Adjustment Values for the SPS-1 and SPS-9 Sections ........................................................................................................ J-174

WS-23 Comparison of the Predicted and Measured Rut Depths Using the Global Calibration Values for the Modified Leahy Transfer Function for the SPS-1 and SPS-9 Projects ....................................................................................... J-175

WS-24 Comparison of the Predicted and Measured Rut Depths and Residual Error Using the Global Values for the Verstraeten Deviator Stress Transfer Function for the SPS-1 and SPS-9 Sections ................................................... J-175



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WS-25 Comparison of the Predicted and Measured Rut Depths and Residual Error Using the Global Values for the WesTrack Shear Strain and Stress Transfer Function for the SPS-1 and SPS-9 Sections ..................................... J-176

WS-26 Comparison of the Predicted and Measured Rut Depths made at different Times for Section 0113 Using the Global Constants of the different Transfer Function ............................................................................................ J-176

WS-27 Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0113 and 0114; without an ATB Layer .......................................................................... J-178

WS-28 Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0116 and 0117; with an ATB Layer ............................................................................... J-179



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ACKNOWLEDGEMENTS The research described herein was performed under NCHRP Project 9-30A by the Transportation Sector of Applied Research Associates (ARA), Inc. Mr. Harold L. Von Quintus served as the Principal Investigator on the project. Mr. Von Quintus was assisted by Mr. Jagannath Mallela as the Project Manager and Engineer on the team. Other management team members and subcontractors included Dr. Charles Schwartz, P.E. of the University of Maryland, and Dr. Ramon Bonaquist of Advanced Asphalt Technologies, LCC. Both Dr. Schwartz and Bonaquist served as Co-Principal Investigators on the project. One of the major efforts of NCHRP project 9-30A was to use rut depth time series data for calibrating and validating the different rut depth transfer functions that were recommended for use from the Facilitated Workshop (documented in Appendix G of this report series). These different rut depth transfer functions were embedded in version 9-30A of the Mechanistic-Empirical Pavement Design Guide (MEPDG) software. Rut depth time series data, pavement structural properties, and other site feature properties for determining the level 1 inputs to the software were obtained from numerous sources for this work. The project team acknowledges and appreciates the support and assistance of various agency and contractor personnel that provided field and laboratory data and support for the forensic investigations of multiple test sections included within NCHRP project 9-30A. The individuals involved in coordination and data collection for specific test sections are listed below.

Drs. Nam Tran and Buzz Powell with the National Center of Asphalt Technologies (NCAT) for providing measured rut depths and samples of the HMA mixtures placed on specific test sections at the NCAT test track. In addition, Dr. Nam Tran provided additional laboratory test data for some of the HMA mixtures and test sections being monitored at the NCAT test track in comparison to those mixtures tested under NCHRP project 9-30A.

Dr. Sirus Alavi with Transportation Engineers (contractor on the Long Term Pavement Performance [LTPP] program) for coordinating, scheduling, and shipping component materials from the LTPP Materials Research Library in Reno, Nevada. These materials were used in the production test program for calibrating the different transfer functions considered and evaluated within the study.

Mr. John Donahue with the Missouri Department of Transportation for providing materials and mixture design information for Missouri’s LTPP SPS-5 project.

Dr. Fee Fong with the Texas Transportation Institute (TTI) for assisting with the coordination of the forensic investigation of the Texas LTPP SPS-5 project.

Mr. William Barstis with the Mississippi Department of Transportation and Mr. Gaylon Baumgardner with Paragon Technical Services, Inc. for providing information and additional materials used on Mississippi’s LTPP SPS-5 project.



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Mr. Steve Krebs and Mrs. Laura Fenley with the Wisconsin Department of Transportation for providing mixture design information and assistance with trenching the Wisconsin LTPP SPS-1 and SPS-9 projects. Dr. Erv Dukatz with Mathy Construction provided additional samples of the fine and coarse aggregate that were used in production to complete the production test program for the Wisconsin projects.

Ms. Sue Sillick and Mr. Jon Watson with the Montana Department of Transportation for providing materials, mixture data, and assess to Montana’s LTPP SPS-5, SPS-1, and SPS-9 projects.

Mr. Kevin Senn with Nichols Consulting and Ms. Judie Kliewer with the Arizona Department for providing access to and assistance with the forensic investigation of Arizona’s LTPP SPS-5 project.

Mr. Robert Long with Burns Cooley Dennis, Inc. participated as a member of the forensic investigation team.

All members of the research team also acknowledge and greatly appreciate the support and effort for helping bring this project to completion by Dr. Edward Harrigan with NCHRP and the NCHRP panel members.



J - xv

ABSTRACT The objective of NCHRP Project 9-30A was to recommend revisions to the hot mix asphalt (HMA) rut depth transfer function in the Mechanistic-Empirical Pavement Design Guide Software. The recommended revisions were based on the calibration of rut depth transfer functions with laboratory measured mixture properties and performance data from existing field and other full-scale pavement sections that incorporate modified as well as unmodified asphalt binders. As part of this objective, permanent deformation parameters, dynamic modulus, and other HMA properties were measured on HMA specific mixtures from multiple full-scale test sections and roadway segments. These mixture specific properties were used to calibrate and validate the different rut depth transfer functions that were recommended for use from the facilitated workshop, documented in Appendix G. The documentation for NCHRP Project 9-30A consists of a final report and eleven appendices (Appendix A through K). This appendix documents the full-scale test sections and forensic investigations that were used to calibrate the different rut depth transfer functions. This work will be of interest to industry (contractors, university personnel, and consultants) and highway design and research engineers that are involved in local calibration studies of the MEPDG transfer functions, as well as other mechanistic-empirical based transfer functions.



J - xvi

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National Cooperative Highway Research Program NCHRP 9-30A

Calibration of Rutting Models for HMA Structural and Mixture Design

Appendix J Forensic Investigation and Evaluation of the Test Sections

Used for Calibration J-1 INTRODUCTION J-1.1 Background Model calibration and validation requires the assembly and analysis of large quantities of data. The purpose of Appendix J is to document the full-scale test sections that were used to calibrate and validate the rut depth transfer functions embedded in version 9-30A of the MEPDG software. It also provides a summary and evaluation of the predicted and measured rut depths made with that version of the software. In addition, the evaluation and forensic investigations conducted on some of the full-scale test sections used in the calibration and comparison of the different rut depth transfer functions is presented and documented in this appendix. The rut depth transfer functions selected for consideration from the facilitated workshop (see Appendix G) are listed in the next section of the Introduction. Two sets of runs were executed for each transfer function: one set using the global calibration parameters, and a second set to determine the field-derived plastic deformation or strain parameters to eliminate any bias and reduce the standard error of the estimate to the lowest value possible of the transfer functions. The field-derived plastic deformation coefficients were used to determine the difference with the laboratory-derived coefficients, which were explained in the final report. For the solutions using the global plastic deformation coefficients of the different transfer functions, only one set of plastic deformation parameters were used for all HMA layers. For all test sections, the “best available” data were used for the inputs, including the measured dynamic moduli. Input level 3 default values were only used for those parameters that were unavailable from the historical records, mixture design sheets, and construction files, unless stated differently in the discussion of each test section. J-1.2 Rut Depth Transfer Functions As noted above, each transfer function was used without any change in predicting the measured rut depths for multiple test sections, with the exception of the NCHRP 1-40B Mix Adjustment version transfer function, as referred to below. It is assumed that any difference in rut depth can be explained by variations in dynamic modulus and the computed pavement response parameters. In other words, the coefficients of the transfer function remain the same for the different mixtures within and between the test sections. The rut depth transfer functions included in the software to predict the measured rut depths include:

1. MEPDG vertical strain transfer function and referred to in this appendix as the Kaloush-Witczak or Kaloush model (equation 1 in the final report).

2. MEPDG vertical strain transfer function but modified using the mixture dependent plastic strain coefficients – reported under NCHRP project 1-40B (referred to as the NCHRP 1-



J - 2

40B Mix Adjustment version). These plastic deformation coefficients are dependent on the mixture volumetric properties (see section 2.1.2.2 in the final report).

3. Asphalt Institute or Leahy vertical strain and deviator stress transfer function (equation 5 in the final report).

4. Modified Leahy vertical strain and deviator stress transfer function (equation 6 in the final report). This transfer function is one initially developed by Leahy but excluding the mixture and binder properties that are used to compute the dynamic modulus of the HMA mixtures in accordance with the Witczak dynamic modulus regression equation embedded in the MEPDG. The modified Leahy transfer function generally provided a more accurate simulation of the measured rut depths in comparison to the original Asphalt Institute transfer function. However, when both the Asphalt Institute and modified Leahy transfer functions were calibrated to specific mixtures, both provided similar predictions of the measured rut depths. Thus, the use of both transfer functions were only included in Appendix J for a few of the test sections.

5. Verstraten deviator stress transfer function (equation 7 in the final report). 6. WesTrack shear strain and stress transfer function (equation 8 in the final report).

The plastic strain coefficients of the transfer functions were also adjusted or changed to remove any bias between the predicted and measured rut depths and minimize the standard error of the estimate on a test section basis. These field-derived plastic strain coefficients were compared to the laboratory-derived plastic strain coefficients, which are presented and discussed in the report itself. The comparison between the measured and predicted rut depths using the global transfer functions and the field-derived coefficients are summarized for each test section and in the final report. In addition, those LTPP projects with multiple test sections were used to determine or identify structural and mixture features that were found to have an impact of the field-derived plastic deformation coefficients.



J - 3

J-2 ALABAMA SPS-6 PROJECT

Construction Date: 6-23-1998 Elevation: 1335 Route: IH-59 Latitude: 34.18

Functional Class: 1 Longitude: -85.96 AADTT (Both Directions): 2,225 Soil Type: Clayey Gravel &

Gravelly Silt The Alabama SPS-6 project is located on Interstate Highway 59 in Etowah County, Alabama. IH 59 is a four-lane divided highway. J-2.1 Construction History The original rigid pavement was built and opened to traffic in August 1964. The HMA overlay was placed in 1998 and opened to traffic in June 1998. No construction issues were identified from the construction report. No maintenance or rehabilitation was applied to the overlaid pavement within the monitoring

period for measuring rut depths. J-2.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table AL-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B).

Table AL-1. Summary of Average Layer Thickness from LTPP Database

Test Section

Material Type and Thickness HMA Overlay Existing PCC Pavement

PCC Condition

HMA Surface

HMA Binder

HMA Base, 25 mm

PCC Surface

Crushed Stone Base

0603 Intact Slab 1.1 2.5 --- 10.2 6 0604 Intact Slab 1.3 2.7 --- 10.3 6 0606 Intact Slab 1.3 2.2 --- 10.3 6 0607 Crack & Seat 1.3 3.0 --- 10.1 6 0608 Crack & Seat 1.5 2.2 4.5 10.2 6 0661 Rubblized 1.1 2.3 --- 10.7 6 0662 Rubblized 1.4 2.2 4.0 10.2 6 0663 Rubblized 1.6 2.2 5.2 10.3 6

All test sections were included for comparing the different transfer functions and test procedures. All test sections were used because of the different overlay thickness and change in layer structure between intact, crack and seat, and rubblized test sections. The same asphalt concrete mixture was placed on all of the SPS-6 core test sections. The following provides a more detailed description of the test sections and the condition of the PCC slabs for the experiment.

0603: Intact PCC slabs; minimum preparation of surface prior to overlay; HMA overlay thickness is 3.6 in

0604: Saw and seal HMA overlay above joints; HMA overlay thickness is 4.0 in. 0606: Maximum preparation of surface prior to overlay; HMA overlay thickness is 3.5 in 0607: Crack and seat PCC slabs; HMA overlay thickness is 4.3 in. 0608: Crack and seat PCC slabs; HMA overlay thickness is 8.2 in.



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0661: Rubblize PCC slabs; HMA overlay thickness is 3.4 in. The 0.61 m end of this test section did not get rubblized, so it will be excluded from the possible test sections.

0662: Rubblize PCC slabs; HMA overlay thickness is 9.0 in. 0663: Rubblize PCC slabs; HMA overlay thickness is 9.0 in.

J-2.3 Material Properties Reported During Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Those properties extracted from the LTPP database that were measured during construction and used to reconstitute the test specimens are summarized below.

Aggregate Properties for HMA Overlay Mixtures: Type of aggregate included in the mixture design for all three mixtures used within this

experiment was a crushed limestone, coarse sand, and slag. The following lists the aggregate percentages used to establish the job mix formula for all mixtures used within this SPS-6 project.

Aggregate Type Aggregate Percentages

Surface Mix, 19 mm

Binder Mix, 25 mm

Base Mix, 25 mm

#8910 Mod. Limestone 25 24 40 #6 Limestone 5 --- --- #78 Limestone --- 34 39 #57 Limestone --- 31 --- #8910 B.F. Slag 15 --- --- #78 B.F. Slag 44 --- --- Coarse Sand 10 10 20 Baghouse Fines 1 1 1 Aggregate Bulk Specific Gravity; Design

2.581 2.694 2.661

Fine Aggregate Angularity – Not reported in LTPP database, but mix

design records report 45 to 48. Fine Aggregate bulk specific gravity – Not reported in LTPP database or on

mixture design sheets. Coarse Aggregate Angularity – Not reported in LTPP database, but mix

design records report 97 to 100 percent. Coarse Aggregate specific gravity – Not reported in LTPP database or on

mixture design sheets. Total Aggregate Absorption – Approximately 2 percent Aggregate Blend for the different layers or mixtures: The following percent passing

values are averages from the LTPP database.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #8 #16 #50 #200 Surface 100 100 100 96 80 47 32 23 11 5.4 Binder 100 100 96 84 69 35 24 18 9 4.6 Base 100 100 100 98 86 54 37 18 7 4.6



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Asphalt Properties: Asphalt Specific Gravity, PG 76-22 – 1.037 Asphalt Specific Gravity, PF 64-22 – 1.04 Total asphalt content by weight: The total asphalt content and asphalt grade used within

each layer is tabulated below.

Asphalt Type Asphalt Content for Mixture Type

Surface Mix, 19 mm

Binder Mix, 25 mm

Base Mix, 25 mm

PG 76-22, Hunt Oil Co. 5.5 4.4 --- PG 64-22, Hunt Oil Co. --- --- 5.2

HMA Mixture Properties: No anti-strip additives were included in the mixture; all TSR values were significantly greater than the required value of 70 percent. The following summarizes the HMA volumetric properties for each of the mixtures included in the SPS-6 experiment. As tabulated, the maximum specific gravities reported by LTPP are significantly different than recorded on the mixture design sheets. More importantly, the air voids calculated for the 1.25 inch wearing surface are high. One reason for the higher air voids could be related to the temperature loss during construction for these thin layers.

HMA Mix Property Asphalt Content for Mixture Type

Surface Mix, 19 mm

Binder Mix, 25 mm

Base Mix, 25 mm

Max. Specific Gravity, Design 2.429 2.531 2.484 Max. Specific Gravity, LTPP 2.4953 2.3818 2.3688 Average Air Voids 12.4 5.6 5.9

J-2.4 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. Figure AL-1 presents the dynamic modulus values measured on the HMA overlay with the polymer modified asphalt, which were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E. J-2.5 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section report. The maximum rut depths measured along the individual test sections varied from 0.118 to 0.236 inches—very low levels of rutting. Figure AL-2 shows the measured rut depths over time for all test sections within the SPS-6 project. As shown, the rut depths are low. The following lists the average maximum rut depths measured on the sections with the different conditions of the existing PCC slabs.

Statistical Parameter Intact Slabs Crack & Seat Rubblized Mean Max. Rut Depth, in. 0.118 0.177 0.184 Standard Deviation, in. 0.0 .0834 0.0601 Coefficient of Variation, % 0.0 47.1 32.7



J - 6

Test sections 607 and 661 exhibited the higher rut depths measured over time. The cause or reason for the higher rut depths is unknown. Figure AL-3 shows the effect of HMA overlay thickness on the maximum rut depth measured along each of the SPS-6 test sections. As shown, HMA overlay thickness has no effect on the rut depths for this SPS-6 project.

Figure AL-1. Dynamic Modulus Values Measured on the HMA Overlay Mixture with the

Polymer Modified Asphalt

Figure AL-2. Rut Depths Measured Over Time for Each SPS-6 Test Section with an HMA

Overlay

0

0.05

0.1

0.15

0.2

0.25

0.00 2.00 4.00 6.00 8.00 10.00

Age, years

Av

era

ge

Ma

x.

Ru

t D

ep

th,

in.

603

604

606

607

608

661

662

663



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Figure AL-3. Effect of HMA Overlay Thickness on Maximum Rut Depth

In summary, these test sections have exhibited minimal rutting. These rut depths are so low it would be difficult to determine the amount of rutting within the different layers considering the variation in thickness profiles caused by the paver and PCC slabs. Thus, this project was not identified as a candidate for the forensic investigations under NCHRP Project 9-30A. Based on an analysis of the measured rut depths, all measurable rutting has occurred in the

HMA overlay. The wearing surface is approximately 1.25 inches in thickness and the thicker HMA base mixture (4.5 inches) was only placed on three of the test sections—all of which had lower rut depths. Thus, the lower binder layer or mixture was tested because this is the layer that was placed on all of the PCC slabs, is believed to have exhibited most of the rutting, and has sufficient material in the MRL to support the production testing program.

J.2.6 Rut Depth Predictions Using the Global Transfer Function Coefficients Figures AL-4 through AL-6 include a comparison of the predicted and measured rut depths for the SPS-6 sections for different conditions of the JPCP slabs. For these solutions, only one set of plastic deformation coefficients were used for all HMA layers to be consistent with the global transfer function. Table AL-2 provides a summary of the bias (predicted minus measured rut depth) and standard error of the estimate for the different transfer functions. As shown and summarized, the Asphalt Institute and MEPDG (or Kaloush) transfer functions significantly over predict the measured rut depths. Conversely, the WesTrack, and Modified Leahy transfer functions have a much lower bias in the predicted values. The asphalt concrete mix dependent coefficients of the NCHRP project 1-40B transfer function also provides a closer estimate to the measured values.

0

0.05

0.1

0.15

0.2

0.25

3 4 5 6 7 8 9 10

HMA Overlay Thickness, in.

Ave

rag

e M

ax.

Ru

t D

epth

, in

.

Intact Slabs Crack & Seat Slabs Rubblized Slabs



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Table AL-2. Bias and Standard Error of the Estimate for the Rut Depth Transfer Functions

Transfer Function Bias, inches Standard Error of the

Estimate, inches Kaloush, MEPDG & Baseline 0.181 0.099 Asphalt Institute 0.575 0.219 Modified Leahy 0.083 0.044 NCHRP 1-40B, Equivalent 0.067 0.097 Verstraeten 0.089 0.087 WesTrack 0.086 0.121 J.2.7 Field-Derived Coefficients of the Transfer Functions The measured rut depths were used to determine the coefficients of each transfer function to eliminate the bias shown in Figures AL-4 through AL-6 and reduce the standard error of the estimate to the lowest possible value for each transfer function. Figures AL-7 and AL-8 includes examples of the predicted and measured rut depths for each transfer function using the field matched or field-derived plastic strain coefficients for each transfer function. Table AL-3 summarizes the field-derived coefficients of each transfer function and test section, while Table AL-4 includes a summary of the bias and standard error of the estimate using the field-derived values. As shown, each transfer function can accurately predict the measured rut depths. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.



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Figure AL-4. Intact PCC Slab Sections: Predicted versus Measured Rut Depths using

MEPDG Version 9-30A and the Global Plastic Deformation Values

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9

Age, years (Alabama SPS-0604)

Ru

t D

epth

, in

ches

Verstraten, Global

Asphalt Institute,Global

WesTrack, Global

NCHRP 1-40B,Equivalent

MEPDG, Global

Measured Values

Modified Leahy

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9

Age, years (Alablama SPS-0606)

Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

Modified Leahy

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraeten, Global

WesTrack, Global

MEPDG, Global


Measured Values


Modified Leahy



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Figure AL-5. Crack and Seat Sections: Predicted versus Measured Rut Depths using

MEPDG Version 9-30A and the Global Plastic Deformation Values.

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

WesTrack, Global

Verstraeten, Global

MEPDG, Global

Measured Values



Modified Leahy

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraeten, Global

WesTrack, Global

MEPDG, Global


Measured Values


Modified Leahy



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Figure AL-6. Rubblized Test Sections: Predicted versus Measured Rut Depths using

MEPDG Version 9-30A and the Global Plastic Deformation Values.

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

Modified Leahy

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

Modified Leahy

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

Modified Leahy



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Table AL-3. Field-Derived Slope and Intercept

Coefficient Test

Section Kaloush

Asphalt Institute

Modified Leahy

Verstraeten WesTrack

Slope All 0.22 0.22 0.22 0.22 0.22

Intercept

0603-Intact -2.623 0.682 80 2.462 0604-Intact -2.655 0.725 75 2.642 0606-Intact -2.700 0.750 78 2.500 0607-C&S -2.380 0.332 85 1.091 0608-C&S -2.530 0.704 43 0.500 0661-Rub. -2.030 0.500 28 0.428 0662-Rub. -2.450 0.650 46 0.569 0663-Rub. -2.389 -6.17 0.750 38 0.400

Table AL-4. Bias and Standard Error of the Estimate for the Rut Depth Transfer Functions Using the Field-Derived Values

Transfer Function Bias, inches Standard Error of the

Estimate, inches Kaloush, MEPDG & Baseline 0.0039 0.0313 Asphalt Institute -0.0032 0.0330 Modified Leahy 0.0056 0.0309 NCHRP 1-40B, Equivalent 0.0051 0.0306 Verstraeten 0.0087 0.0310 WesTrack 0.0066 0.0315



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Figure AL-7. Examples of Predicted versus Measured Rut Depths for the Fractured PCC Slab Test Sections Using MEPDG Version 9-30A and the Field-Derived Values (see Table

AL-3).

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraeten

AI Leahy

WesTrack

MEPDG

1-40B AdjustmentFactors

Measured Values

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9


Ru

t D

epth

, in

ches

Verstraeten

WesTrack

AI Leahy

MEPDG

1-40B AdjustmentFactors

Measured Values



J - 14

Figure AL-8. Examples of Predicted versus Measured Rut Depths for the Intact PCC Test

Sections Using MEPDG Version 9-30A and the Field-Derived Values (see Table AL-3).



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J-2.8 NCHRP 1-40B Mixture Adjustment Factors

Project Identification:

Surface Binder Base

Bulk Specific Gravity Gmb 2.1848 2.3818 2.3668

Maximum Specific Gravity Gmm 2.4953 2.522 2.514

Air Voids, % Va 12.44 5.56 5.86

Air Voids for Target Asphalt Content, % Va(design) 4.10 4.50 4.00

Total Asphalt Content by Weight, % Pb 5.50 4.40 5.20

Optimum/Saturation Asphalt Content, % Pb(0pt) 5.80 4.70 5.80

Aggregate Effective Specific Gravity Gse 2.718 2.700 2.727

Bulk Specific Gravity of Aggregate Blend Gsb 2.582 2.566 2.591

Effective Asphalt Content by Volume, % Vbe 7.606 5.714 7.541

Voids in Mineral Aggregate, % VMA 20.0 11.3 13.4Voids Filled with Asphalt, % VFA 37.9 50.7 56.3

Gradation Factor (GI Term) Kr3 0.80 0.80 0.70

Fine Aggregate Factor Findex 0.90 0.90 0.90

Coarse Aggregate Factor Cindex 0.90 0.90 0.90

Log Kr1 3.25 2.39 2.35

Rut Depth Coefficient kr1 -1.563 -2.730 -2.637

Temperature Exponent kr2 1.561 1.227 1.213

Traffic Loadings Exponent kr3 0.363 0.359 0.301

Asphalt Specific Gravity Gb 1.037 1.037 1.037

Kr1 Value 1778.2794 245.47089 223.87211Absorbed Asphalt by Weight, % 2 2 2kr1 Log Value 76.86521 5.2292244 6.476191

Alabama SPS-6 Sections

Layer Identification



J - 16

J-2.9 Average Rut Depth Measurements Extracted from LTPP Database

LTPP Data Element: MAX_MEAN_DEPTH_WIRE_REF

Section Date Age, years Rut Depth, in.0603 28-Jun-98 0.01 0.0390603 01-Oct-99 1.27 0.0390603 05-Feb-00 1.62 0.0790603 27-Sep-00 2.27 0.0390603 15-Nov-01 3.40 0.0390603 14-Jan-02 3.56 0.1180603 10-Oct-02 4.30 0.0390603 30-Oct-03 5.36 0.0790603 19-Jan-04 5.58 0.0790603 07-Oct-04 6.30 0.0790603 13-Sep-06 8.23 0.079

0604 28-Jun-98 0.01 0.0390604 01-Oct-99 1.27 0.0390604 05-Feb-00 1.62 0.1180604 27-Sep-00 2.27 0.0390604 15-Nov-01 3.40 0.0390604 14-Jan-02 3.56 0.1180604 10-Oct-02 4.30 0.0390604 30-Oct-03 5.36 0.0790604 19-Jan-04 5.58 0.1180604 06-Oct-04 6.29 0.0790604 13-Sep-06 8.23 0.079

0606 28-Jun-98 0.01 0.0390606 01-Oct-99 1.27 0.0390606 05-Feb-00 1.62 0.0790606 27-Sep-00 2.27 0.0390606 15-Nov-01 3.40 0.0390606 14-Jan-02 3.56 0.1180606 09-Oct-02 4.30 0.0390606 29-Oct-03 5.35 0.0790606 19-Jan-04 5.58 0.1180606 06-Oct-04 6.29 0.0790606 13-Sep-06 8.23 0.079

0607 29-Jun-98 0.02 0.0390607 30-Sep-99 1.27 0.0790607 05-Feb-00 1.62 0.1180607 26-Sep-00 2.26 0.1180607 14-Nov-01 3.40 0.1570607 14-Jan-02 3.56 0.2360607 08-Oct-02 4.30 0.1970607 28-Oct-03 5.35 0.1570607 19-Jan-04 5.58 0.1970607 05-Oct-04 6.29 0.1970607 12-Sep-06 8.23 0.118

0608 29-Jun-98 0.02 0.0390608 30-Sep-99 1.27 0.0390608 05-Feb-00 1.62 0.0790608 26-Sep-00 2.26 0.0790608 15-Nov-01 3.40 0.0790608 14-Jan-02 3.56 0.1180608 08-Oct-02 4.30 0.0790608 28-Oct-03 5.35 0.0790608 19-Jan-04 5.58 0.1180608 05-Oct-04 6.29 0.0790608 12-Sep-06 8.23 0.118

0661 28-Jun-98 0.01 0.0390661 01-Oct-99 1.27 0.0790661 05-Feb-00 1.62 0.1180661 27-Sep-00 2.27 0.1570661 14-Jan-02 3.56 0.1970661 09-Oct-02 4.30 0.2360661 29-Oct-03 5.35 0.197

0662 29-Jun-98 0.02 0.0790662 01-Oct-99 1.27 0.0790662 05-Feb-00 1.62 0.0790662 26-Sep-00 2.26 0.0790662 14-Jan-02 3.56 0.1180662 09-Oct-02 4.30 0.0790662 29-Oct-03 5.35 0.0790662 19-Jan-04 5.58 0.1180662 05-Oct-04 6.29 0.1180662 12-Sep-06 8.23 0.118

0663 29-Jun-98 0.02 0.0390663 30-Sep-99 1.27 0.0790663 05-Feb-00 1.62 0.0790663 26-Sep-00 2.26 0.0790663 14-Jan-02 3.56 0.1180663 08-Oct-02 4.30 0.0790663 29-Oct-03 5.35 0.0790663 19-Jan-04 5.58 0.1970663 05-Oct-04 6.29 0.1180663 12-Sep-06 8.23 0.118



J - 17

J-2.10 MEPDG Input Summary: Alabama SPS-6 Test Section Example The following is a copy of the input files for the SPS-6-0607 test section run for predicting rut depths using version 9-30A of the MEPDG and different transfer functions being used for NCHRP Project 9-30A.

Limit Reliability 63 172 90 2000 90 25 90 1000 90 25 90 0.25 90 0.75 90 100

Project: Alabama_SPS06-07

General Information Description:Project located along I-59; a rural interstate roadway. Section 0607 is an 102mm HMA overlay of a cracked and seated JPCP.

Design Life 8 yearsExisting pavement construction: August, 1964Pavement overlay construction: May, 1998Traffic open: June, 1998Type of design Flexible

Analysis Parameters

Performance CriteriaInitial IRI (in/mi)Terminal IRI (in/mi)AC Surface Down Cracking (Long. Cracking) (ft/mile):AC Bottom Up Cracking (Alligator Cracking) (%):AC Thermal Fracture (Transverse Cracking) (ft/mi):Chemically Stabilized Layer (Fatigue Fracture)Permanent Deformation (AC Only) (in):Permanent Deformation (Total Pavement) (in):Reflective cracking (%):

Location: I-59; Gadsden, AlabamaProject ID: SPS-06Section ID: 7 Principal Arterials - Interstate and Defense RoutesDate: 9/18/2007 Station/milepost format: Miles: 0.000Station/milepost begin: 0Station/milepost end: 1Traffic direction: East bound

Default Input LevelDefault input level Level 3, Default and historical agency values.



J - 18

2225 2 55 95 60

Class 4 Class 5 Class 6 Class 7 Class 8 Class 9 Class 10 Class 11 Class 12 Class 13

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

Midnight 2.3% Noon 5.9% 1.3% 1:00 am 2.3% 1:00 pm 5.9% 8.5% 2:00 am 2.3% 2:00 pm 5.9% 2.8% 3:00 am 2.3% 3:00 pm 5.9% 0.3% 4:00 am 2.3% 4:00 pm 4.6% 7.6% 5:00 am 2.3% 5:00 pm 4.6% 74.0% 6:00 am 5.0% 6:00 pm 4.6% 1.2% 7:00 am 5.0% 7:00 pm 4.6% 3.4% 8:00 am 5.0% 8:00 pm 3.1% 0.6% 9:00 am 5.0% 9:00 pm 3.1% 0.3% 10:00 am 5.9% 10:00 pm 3.1% 11:00 am 5.9% 11:00 pm 3.1%

3.6% 3.6% 3.6% 3.6% 3.6% 3.6% 3.6% 3.6% 3.6% 3.6%

18 10 12

1.62 0.39 0.00 0.00 2.00 0.00 0.00 0.00 1.02 0.99 0.00 0.00 1.00 0.26 0.83 0.00 2.38 0.67 0.00 0.00 1.13 1.93 0.00 0.00 1.19 1.09 0.89 0.00 4.29 0.26 0.06 0.00 3.52 1.14 0.06 0.00 2.15 2.13 0.35 0.00

8.5 12 120 51.6 49.2 49.2

Traffic Initial two-way AADTT:Number of lanes in design direction:Percent of trucks in design direction (%):Percent of trucks in design lane (%):Operational speed (mph):

Traffic -- Volume Adjustment FactorsMonthly Adjustment Factors (Level 3, Default MAF)

Vehicle ClassMonth

JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember

Vehicle Class Distribution Hourly truck traffic distribution(Level 3, Default Distribution) by period beginning:

AADTT distribution by vehicle classClass 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12Class 13

Traffic Growth Factor

Vehicle Class

Growth Rate

GrowthFunction

Class 4 CompoundClass 5 CompoundClass 6 CompoundClass 7 CompoundClass 8 CompoundClass 9 CompoundClass 10 CompoundClass 11 CompoundClass 12 CompoundClass 13 Compound

Traffic -- Axle Load Distribution FactorsLevel 3: Default

Traffic -- General Traffic InputsMean wheel location (inches from the lane marking):Traffic wander standard deviation (in):Design lane width (ft):

Number of Axles per Truck

Quad Axle

Class 4Class 5Class 6

Vehicle Class

Single Axle

Tandem Axle

Tridem Axle

Class 7Class 8Class 9Class 10Class 11Class 12Class 13

Axle ConfigurationAverage axle width (edge-to-edge) outside dimensions,ft):Dual tire spacing (in):

Axle ConfigurationTire Pressure (psi) :

Average Axle SpacingTandem axle(psi):Tridem axle(psi):Quad axle(psi):



J - 19

33.34 -86.45 639 20

-10 -16 -22 -28 -34 -40 -46

LoadTime(sec)

LowTemp.-4ºF

(1/psi)

Mid.Temp.14ºF

(1/psi)

HighTemp.32ºF

(1/psi) 1 2.45E-07 3.79E-07 5.05E-07 2 2.67E-07 4.39E-07 6.41E-07 5 3E-07 5.34E-07 8.79E-07 10 3.27E-07 6.2E-07 1.12E-06 20 3.57E-07 7.19E-07 1.42E-06 50 4E-07 8.75E-07 1.94E-06 100 4.37E-07 1.02E-06 2.46E-06

Climate icm file:

C:\DG2002\Projects\Gadsden, Alabama.icm Latitude (degrees.minutes)Longitude (degrees.minutes)Elevation (ft)Depth of water table (ft)

Structure--Design Features

HMA E* Predictive Model: NCHRP 1-37A viscosity based model.HMA Rutting Model coefficients: NCHRP 1-37A coefficientsEndurance Limit (microstrain): None (0 microstrain)Reflective cracking analysis: Yes

Structure--Layers Layer 1 -- Asphalt concrete

Material type: Asphalt concreteLayer thickness (in): 4.3

General PropertiesGeneralReference temperature (F°): 70

Volumetric Properties as BuiltEffective binder content (%): 10.2Air voids (%): 5.3Total unit weight (pcf): 151

Poisson's ratio: 0.3 (user entered)

Thermal PropertiesThermal conductivity asphalt (BTU/hr-ft-F°): 0.67Heat capacity asphalt (BTU/lb-F°): 0.23

Asphalt MixCumulative % Retained 3/4 inch sieve: 4Cumulative % Retained 3/8 inch sieve: 31Cumulative % Retained #4 sieve: 65% Passing #200 sieve: 4.6

Asphalt BinderOption: Superpave binder gradingA 10.9800 (correlated)VTS: -3.6800 (correlated)

High temp.°C

Low temperature, °C

46525864707682

Thermal Cracking PropertiesAverage Tensile Strength at 14ºF: 418.16Mixture VMA (%) 15.5Aggreagate coeff. thermal contraction (in./in.) 0.000005Mix coeff. thermal contraction (in./in./ºF): 0.000013



J - 20

Value 7.2555 1.3328 0.82422 117.4

Layer 2 -- JPCP (existing)General Properties

Material type: JPCP (existing)Layer thickness (in): 10.1Unit weight (pcf): 150Poisson's ratio: 0.2

Strength PropertiesElastic/resilient modulus (psi): 1000000

Thermal PropertiesThermal conductivity (BTU/hr-ft-F°) : 1.25Heat capacity (BTU/lb-F°): 0.28

Layer 3 -- Crushed stoneUnbound Material: Crushed stoneThickness(in): 6

Strength PropertiesInput Level: Level 3Analysis Type: ICM inputs (ICM Calculated Modulus)Poisson's ratio: 0.35Coefficient of lateral pressure,Ko: 0.5Modulus (input) (psi): 20000

ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 1Liquid Limit (LL) 6Compacted Layer YesPassing #200 sieve (%): 8.7Passing #40 20Passing #4 sieve (%): 44.7D10(mm) 0.1035D20(mm) 0.425D30(mm) 1.306D60(mm) 10.82D90(mm) 46.19

Sieve Percent Passing0.001mm 0.002mm 0.020mm

#200 8.7#100 #80 12.9#60 #50 #40 20#30 #20 #16 #10 33.8#8 #4 44.7

3/8" 57.21/2" 63.13/4" 72.71" 78.8

1 1/2" 85.82" 91.6

2 1/2" 3"

3 1/2" 97.64" 97.6

Calculated/Derived ParametersMaximum dry unit weight (pcf): 127.7 (derived)Specific gravity of solids, Gs: 2.70 (derived)Saturated hydraulic conductivity (ft/hr): 0.05054 (derived)Optimum gravimetric water content (%): 7.4 (derived)Calculated degree of saturation (%): 62.2 (calculated)

Soil water characteristic curve parameters: Default values

Parametersabc

Hr.



J - 21

Value 108.41 0.68007 0.21612 500

Layer 4 -- A-6Unbound Material: A-6Thickness(in): Semi-infinite


ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 16Liquid Limit (LL) 33Compacted Layer NoPassing #200 sieve (%): 63.2Passing #40 82.4Passing #4 sieve (%): 93.5D10(mm) 0.000285D20(mm) 0.0008125D30(mm) 0.002316D60(mm) 0.05364D90(mm) 1.922


#200 63.2#100 #80 73.5#60 #50 #40 82.4#30 #20 #16 #10 90.2#8 #4 93.5

3/8" 96.41/2" 97.43/4" 98.41" 99

1 1/2" 99.52" 99.8

2 1/2" 3"

3 1/2" 1004" 100

Calculated/Derived ParametersMaximum dry unit weight (pcf): 107.9 (derived)Specific gravity of solids, Gs: 2.70 (derived)Saturated hydraulic conductivity (ft/hr): 1.95e-005 (derived)Optimum gravimetric water content (%): 17.1 (derived)Calculated degree of saturation (%): 82.1 (calculated)


Parametersabc

Hr.



J - 22

0.007566 3.9492 1.281

1 1

-3.35412 1.5606 0.4791

1.5

1 1

2.03 1.35

7 3.5 0 1000 1 1 0 6000

1 1 0 1000

40 0.4 0.008 0.015 40.8 0.575 0.0014 0.00825

Distress Model Calibration Settings - Flexible

AC FatigueLevel 3: NCHRP 1-37A coefficients (nationally calibrated values)

k1k2k3

AC Reflective Crackingc

AC RuttingLevel 3: NCHRP 1-37A coefficients (nationally calibrated values)

k1k2k3

Standard Deviation Total Rutting (RUT):

0.24*POWER(RUT,0.8026)+0.001

Thermal FractureLevel 3: NCHRP 1-37A coefficients (nationally calibrated values)

k1

Std. Dev. (THERMAL): 0.1468 * THERMAL + 65.027

CSM FatigueLevel 3: NCHRP 1-37A coefficients (nationally calibrated values)

k1k2

Subgrade RuttingLevel 3: NCHRP 1-37A coefficients (nationally calibrated values)

Granular:k1

Fine-grain:k1

AC CrackingAC Top Down Cracking

C1 (top)C2 (top)C3 (top)C4 (top)

Standard Deviation (TOP) 200 + 2300/(1+exp(1.072-2.1654*log(TOP+0.0001)))

AC Bottom Up CrackingC1 (bottom)C2 (bottom)C3 (bottom)C4 (bottom)

Standard Deviation (TOP) 1.13+13/(1+exp(7.57-15.5*log(BOTTOM+0.0001)))

CSM CrackingC1 (CSM)C2 (CSM)C3 (CSM)C4 (CSM)

Standard Deviation (CSM) CTB*11

IRIIRI HMA Pavements New

C1(HMA)C2(HMA)C3(HMA)C4(HMA)

C4(HMA/PCC)

IRI HMA/PCC PavementsC1(HMA/PCC)C2(HMA/PCC)C3(HMA/PCC)



J - 23

J-3 Arizona SPS-5 Project


Functional Class: 1 Longitude: -111.99 AADTT (LTPP Lane Only): 610 to 1700 Soil Type: Silty Sand

The SPS-5 project is located about 27 km west of Casa Grande, AZ on Interstate 8, which is a four-lane divided highway. The SPS-5 project is located in the eastbound traffic lane in Pinal County. J-3.1 Construction History The existing flexible pavement was built and opened to traffic in 1987. The HMA overlay was placed and opened to traffic in the summer of 1990. Construction Issues: Low stability was evident in the asphalt rubber mix. In addition, when

placing the first of three lifts, the average temperature behind the paver was low causing some concern in achieving adequate density in the HMA mixture. The air voids on all of the HMA overlay mixtures do not suggest a compaction problem.

The sections of the SPS-5 project received periodic maintenance activities during the monitoring period for measuring rut depths. The different maintenance and rehabilitation activities are listed below.

o May 1998 a fog seal was placed on all test sections. o August 2001 a fog seal was placed on all test sections. o May 2002 a fog seal was placed on all test sections with the exception of 0503, 0504,

0507, and 0508. o April 2003 a thin HMA overlay was placed. Figure AZ-1 shows the average rut

depths measured over time for selected sections. The thin HMA overlay reduced the rut depths back to zero in early 2003. Thus, the rut depths measured through 2002 were the only ones used in the comparison of the predicted and measured rut depths for the different transfer functions.

The SPS-5 project was taken out of service in September 2008. The pavement forensic investigation was completed prior to taking the project out of service. The thin overlay was included in the forensic investigation.

J-3.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table AZ-1 summarizes the pavement cross section for each test section. All test sections were included for comparing the different transfer functions and test procedures, with the exception of section 04-0560. This supplemental test section included an asphalt rubber mixture as part of the overlay and there is insufficient material available in the MRL for testing this mixture.



J - 24

Figure AZ-1. Average Maximum Rut Depths Measured with Time

Table AZ-1. Summary of Average Layer Thickness from LTPP Database

Test Section

Layer Type and Thickness HMA Overlay Existing Pavement

Mix Type Lift Thickness HMA Layers Granular Base 0502 RAP Mix 2.7 --- 3.7 14.7 0503 RAP Mix 4.7 --- 4.2 16.6 0504 Virgin Mix 4.8 --- 4.3 17.6 0505 Virgin Mix 2.8 --- 4.1 12.8 0506 Virgin Mix/Mill 2.4 2.8 3.0 12.8 0507 Virgin Mix/Mill 4.1 2.7 2.4 20.7 0508 RAP Mix/Mill 4.1 2.4 2.7 15.0 0509 RAP Mix/Mill 1.3 2.6 2.6 14.8 0559 RAP Mix/Mill 3.0 3.0 1.7 13.2 0560 Rubber Mix/Mill 2.2 --- 4.1 14.0

J-3.3 Material Properties Reported During Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Those properties extracted from the LTPP database that were measured during construction and used to reconstitute the test specimens for the production testing program are summarized below. [It should be noted that multiple lifts were placed on some of the sections. However, only two mixtures (the same structural layer) were included in the production testing program—those mixture/material properties for the two mixtures are summarized below. The mixture design sheets were unavailable for review from this project.]

Aggregate Properties for HMA Overlay Mixtures: Fine Aggregate Angularity – No data reported Fine Aggregate bulk specific gravity – 2.570 Fine Aggregate Absorption (water) – 1.05 Coarse Aggregate Angularity – No data reported. Coarse Aggregate specific gravity – 2.547 Coarse Aggregate Absorption (water) – 0.88

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12 14 16

Age, years

Ave

rag

e R

ut

Dep

th, i

n.

0502-RAP; Thin

0503-RAP; Thick

0504-Virgin; Thick

0505-Virgin; Thin

Thin HMA overlay placed as a maintenance activity in 2003;

rut depths decreased.



J - 25

Mixture #1—RAP Mixture and Test Sections: Asphalt grade used in RAP mix – AC-20 Asphalt Specific Gravity – 1.058 Total asphalt content by weight – 4.9 Maximum Specific Gravity – 2.4163 Average Air Voids – 4.8 Aggregate Blend for the RAP Mixture:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Passing, % 100 100 98 88 82 64 47 23 10.0 6.2

Mixture #2—Virgin Mixture and Test Sections: Asphalt grade used in virgin mix – AC-40 Asphalt Specific Gravity – 1.026 Total asphalt content by weight – 4.5 Maximum Specific Gravity – 2.4163 Average Air Voids – 4.8 Aggregate Blend for the Virgin Mixture:


Existing HMA Layer/Mixture: Asphalt Specific Gravity – 1.1076 Asphalt Content by Weight – 3.98 Maximum Specific Gravity – 2.414 Air Voids – 7.3 Aggregate Blend for the Virgin Mixture:


J-3.4 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section forensic study report. The maximum rut depths measured along the individual test sections varied from 0.197 (virgin mixture) to 0.433 (RAP mixture) inches—a significant difference between the test sections. This difference is believed to be related to the type of overlay mixture. Figure AZ-2 shows the measured rut depths as a function of time through 2002, as noted above. Mixture type (RAP versus virgin mixes) has a definite effect on the magnitude of the measured rut depths—the sections with the RAP mixture consistently exhibit higher rut depths. Another important observation from this time-series data is the amount of variation in the measured rut depths for an individual test section. The following lists the average maximum rut depths measured on the sections with the different HMA mixtures (RAP versus virgin mixes).

Statistical Parameter RAP Mixtures Virgin Mixtures Mean Max. Rut Depth, in. 0.403 0.281 Standard Deviation, in. 0.0379 0.1118 Coefficient of Variation, % 9.4 39.8

Figure AZ-3 shows the effect of HMA overlay thickness and mixture type on the maximum rut depth measured along each of the SPS-5 test sections. As shown, the test sections with the virgin



J - 26

mixtures have rut depths less than those measured along the sections with the RAP mixtures, with the exception of one section (AZ-0507). The reason for the higher rut depths measured along this section with the virgin mixture is unknown. HMA overlay thickness had not significant effect of the measured rut depths. The Arizona SPS-5 project is different from many of the other SPS-5 projects because the higher rut depths were measured along the sections with the RAP mixtures. Thus, this SPS-5 project was selected for a detailed forensic investigation.

Figure AZ-2. Rut Depths Measured Over Time for Each Test Section

Figure AZ-3. Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0

Age, years

Ru

t D

epth

, in

ches

AZ-0502; RAP Mix

AZ-0503; RAP Mix

AZ-0504 Virgin Mix

AZ-0505 Virgin Mix

AZ-0506 Virgin Mix

AZ-0507 Virgin Mix

AZ-0508 RAP Mix

AZ-0509 RAP Mix

0

0.05

0.10.15

0.2

0.25

0.3

0.350.4

0.45

0.5

0 2 4 6 8


Ave

rag

e M

axim

um

Ru

t D

epth

, in

.

RAP Mixes

Virgin Mixes



J - 27

J-3.5 Forensic Investigation of SPS-5 Project Two trenches were excavated to measure the rut depth within each layer of the pavement structure for sections 04-0509 (figure AZ-4; RAP mixture) and 04-0506 (figure AZ-5; Virgin mixture). ARA engineer Paul Littleton was on site to collect pavement layer thickness measurements from two rutted SPS-5 test sections 04-0506 and 04-0509. Section 04-0506 was designed to be a 5.2-in overlay comprised of 2.4-in virgin HMA surface over 2.8-in binder course. Section 04-0509 was designed to be a 5.2-in recycled asphalt pavement (RAP) overlay comprised of 2.4-in surface and 2.8-in binder course. Trenching was done between ADOT and ARA. Paul Sullivan of ADOT Materials Group and Yathi Yatheepan of Nichols Consulting Engineers were on site to observe the trenching operations. ARA was assisted by Robert James of Burns Cooley Dennis, Inc. Mr. James helped to measure layer thickness and collected the cores to be shipped for laboratory for testing. Trench dimensions were 4 ft wide by 10 ft long and 5 ft deep positioned across the driving lane. Figure AZ-6 shows photos of the 6 cores recovered from section 04-0506 (virgin mixture) while figure AZ-7 shows photos of the cores recovered from section 04-0509 (RAP mixture). Six, 6-in diameter cores were taken from each test section for laboratory testing; the cores were recovered by Nichols Consulting Engineers. These six cores from section 04-0509 and 04-0506 will be tested using the RSCH test to determine the effect of aging on the permanent deformation parameters and to measure the difference in the permanent deformation parameters between the in place RAP and virgin mixtures. Measurements were taken from the pavement surface to a string line stretched taught across the surface of the pavement. Additional string lines were located at each interface between the HMA lifts. These string lines were used to easily locate the interface between the different lifts or layers. All layer thickness measurements were taken at the interface between the layers and not the string line itself. In most cases, the interface could be easily identified. Figures AZ-8 and AZ-9 show the layer thicknesses measured at each layer interface, while the individual layer thickness profiles are shown in figures AZ-10 and AZ-11 for sections 0509 and 0506, respectively. From these figures it would appear that the rutting in section 04-0506 occurred primarily in the surface layer with a maximum of about 0.2 inches at the right wheel path. No appreciable rutting was evident in the lower layers. For section 04-0509, however, the rutting appears to be equally distributed throughout the depth of the HMA overlay at the right wheel path. The thicknesses variations measured across the original or existing HMA layer are believed to be more related to construction deviations.



J - 28

Figure AZ-4. Trench Excavated Within Section

04-0509 (RAP Mixture)

Figure AZ-5. Trench Excavated Within Section 04-0506 (Virgin Mixture)



J - 29

Figure AZ-6. Photographs of Cores Recovered from Sections 04-0506 (Virgin

Mixture)



J - 30

Figure AZ-7. Photographs of Cores Recovered from Sections 04-0509 (RAP

Mixture)



J - 31

0

1

2

3

4

5

6

7

8

9

10

0 12 24 36 48 60 72 84 96 108 120

Dep

th fr

om S

urf

ace,

in

Horizontal Distance from Outer Edge of Lane, in

Surface Binder Original HMA Base

Right Wheelpath Left Wheelpath

Figure AZ-8. Horizontal Depth Profiles for Section 4-0506 Virgin HMA Overlay

0

1

2

3

4

5

6

7

8

9

0 12 24 36 48 60 72 84 96 108 120

Dep

th fr

om S

urf

ace,

in


Surface Binder Original HMA Base

Right Wheelpath Left Wheelpath

Figure AZ-9. Horizontal Depth Profiles for Section 4-0509 RAP Overlay



J - 32

Figure AZ-10. Layer or Lift Thickness Measurements Taken Along the Cut Face of the

Trench Excavated for Section 0509

Figure AZ-11. Layer or Lift Thickness Measurements Taken Along the Cut Face of the

Trench Excavated for Section 0506 Figure AZ-12 and AZ-13 show the differential layer thicknesses measured along the cut face of the trench for both sections (0509 and 0506, respectively). As shown, the differential thickness of the aggregate or crushed stone base and existing HMA layer are almost mirror images of one another. This suggests that the elevation of the aggregate base probably caused some of the differential thickness in the existing HMA layer. In summary, it is difficult to determine the magnitude of the rutting within each of the HMA overlay lifts for these two sections. Two lifts were placed for the overlay, as summarized in table AZ-1. The other feature that makes it difficult to determine the amount of rutting within each

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

5.000

0 20 40 60 80 100 120

Distance from Pavement Edge, in.

Lay

er T

hic

knes

s, i

n.

Surface Binder Original HMA Layer

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

0 20 40 60 80 100 120

Distance from Pavement Edge, in.

Lay

er T

hic

knes

s, i

n.

Wearing Surface Binder Layer Original HMA Layer



J - 33

HMA layer is that fog seals and a thin overlay have been placed at different times prior to the forensic investigation.

Figure AZ-12. Differential Layer Thickness Measured Along the Cut Face of the Trench

for Section 0509

Figure AZ-13. Differential Layer Thickness Measured Along the Cut Face of the Trench

for Section 0506

-0.600

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

0 20 40 60 80 100 120

Offset from Edge of Lane, in.

Dif

fere

nti

al L

ayer

Th

ickn

ess,

R

utt

ing

, in

.

Surface Lift Binder Lift Existing HMA Granular Base

-2.000

-1.500

-1.000

-0.500

0.000

0.500

1.000

0 20 40 60 80 100 120

Offset from Edge of Lane, in.

Dif

fere

nti

al L

ayer

Th

ickn

ess,

R

utt

ing

, i

n.

Surface Lift Binder Lift Original HMA Granular Base



J - 34

Based on an analysis of the measured rut depths, all measurable rutting has occurred in the HMA overlay. Thus, both the RAP and virgin mixtures should be tested. It is expected that immeasurable rutting has occurred in the existing HMA, crushed stone base, and subgrade layers.

J-3.6 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. Figure AZ-14 presents the dynamic modulus values measured on the HMA overlay without RAP (defined as virgin mixtures), which were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E.

Figure AZ-14. Dynamic Modulus Values Measured on the HMA Mixture without RAP

J-3.7 Rut Depth Predictions Using the Global Transfer Function Coefficients Figures AZ-15 and AZ-16 compare the predicted and measured rut depths for all transfer functions using the global rut depth coefficients for sections 0502 and 0505, respectively. Section 0502 (Figure AZ-15) includes RAP, while section 0505 (Figure AZ-16) includes the virgin mixtures. Both of these two SPS-5 test sections have similar pavement structures. The comparison of the predicted and measured rut depths over time for the different rut depth transfer functions using the global plastic deformation coefficients was similar. In general the NCHRP 1-40B, Verstraeten, and WesTrack transfer functions predicted similar growth rates or increases in rut depth over time, although the magnitudes of the predicted rut depths were different. Conversely, the Asphalt Institute and MEPDG predicted significantly greater increases in rut depth over time. This observation was true for the other test sections not shown in Figures AZ-15 and AZ-16.



J - 35

Figure AZ-15. Comparison of the Predicted and Measured Rut Depths Using the Global

Coefficients for each Transfer Function for the SPS-5 Section 0502 (RAP Mixtures)


Coefficients for each Rut Depth Transfer Function for SPS-5 Section 0505 (Virgin Mixtures)



J - 36

J-3.8 Field-Derived Coefficients of the Transfer Functions This section summarizes the comparison of the predicted and measured rut depths using laboratory permanent deformation test results in support of the different rut depth transfer functions. Table AZ-2 summarizes the field-derived coefficients of each transfer function and test section, while Figures AZ-17 and AZ-18 compare the predicted and measured rut depth for the test sections with and without RAP, respectively. The test sections with and without milling exhibited a similar comparison between the measured and predicted rut depths. As shown, each transfer function accurately predicted the measured rut depths. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.

Table AZ-2. Field-Derived Slope and Intercept

Coefficient Test Section Kaloush NCHRP

1-40B Modified

Leahy Verstraeten WesTrack

Slope All 0.20 0.20 0.20 0.20 0.20

Intercept

0502-RAP -1.852 -0.198 0.861 769 0.597 0503-RAP -1.708 -1.296 0.498 255 1.253 0508-RAP -1.687 -1.271 0.164 178 1.34 0509-RAP -1.27 -1.243 0.56 272 1.373 0504-Virgin -1.75 -1.25 0.326 220 1.35 0505-Virgin -1.70 -1.107 0.67 600 2.110 0506-Virgin -1.809 -1.271 0.272 200 1.67 0507-Virgin -1.427 -0.895 0.534 340 3.46



J - 37


Coefficients for each Transfer Function for the Test Sections with RAP Mixtures



J - 38

Figure AZ-18. Comparison of the Predicted and Measured Rut Depths Using the Global Coefficients for each Rut Depth Transfer Function for Test Sections with Virgin Mixtures

(without RAP)



J - 39



RAP Mix Virgin Mix Existing HMA



Air Voids, % Va 4.76 4.84 7.26











Log Kr1 2.50 2.47 2.36





Kr1 Value 316.22777 295.12092 229.0867653Absorbed Asphalt by Weight, % 0.95 0.95 0.95kr1 Log Value 9.4773021 8.2555972 6.088170399

Arizona SPS-5 Project




J - 40


Section Date Age, years Rut Depth, in.

0502 15-Jan-91 0.04 0.2360502 22-Sep-91 0.72 0.1970502 19-Oct-94 3.80 0.2360502 22-Mar-95 4.22 0.3150502 12-Sep-96 5.70 0.2760502 13-Nov-97 6.87 0.2760502 10-Dec-98 7.95 0.3150502 06-Oct-99 8.77 0.3150502 13-Dec-99 8.95 0.4330502 17-Oct-00 9.80 0.2760502 11-Nov-01 10.87 0.3940502 29-Nov-01 10.92 0.3150502 11-Dec-02 11.95 0.3150502 06-Nov-03 12.85 0.1180502 11-Dec-03 12.95 0.3540502 08-Dec-04 13.95 0.4330502 08-Dec-05 14.95 0.433




0505 15-Jan-91 0.04 0.2360505 22-Sep-91 0.72 0.1570505 20-Oct-94 3.80 0.0790505 22-Mar-95 4.22 0.2760505 12-Jul-96 5.53 0.1180505 13-Nov-97 6.87 0.1180505 10-Dec-98 7.95 0.1180505 06-Oct-99 8.77 0.1970505 14-Dec-99 8.96 0.2360505 18-Oct-00 9.80 0.1180505 11-Nov-01 10.87 0.1970505 29-Nov-01 10.92 0.1570505 12-Dec-02 11.95 0.1570505 06-Nov-03 12.85 0.1180505 12-Dec-03 12.95 0.1970505 08-Dec-04 13.95 0.2360505 08-Dec-05 14.95 0.236





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0559 06-Oct-99 8.77 0.1970559 20-Oct-94 3.80 0.1180559 22-Mar-95 4.22 0.1570559 14-Nov-97 6.87 0.1180559 10-Dec-98 7.95 0.1180559 18-Oct-00 9.80 0.1180559 14-Dec-99 8.96 0.1570559 11-Nov-01 10.87 0.2360559 30-Nov-01 10.92 0.1570559 12-Dec-02 11.95 0.1180559 06-Nov-03 12.85 0.1570559 12-Dec-03 12.95 0.157

0560 20-Oct-94 3.80 0.1570560 22-Mar-95 4.22 0.2360560 14-Nov-97 6.87 0.1570560 10-Dec-98 7.95 0.1970560 06-Oct-99 8.77 0.2760560 14-Dec-99 8.96 0.1970560 18-Oct-00 9.80 0.1180560 11-Nov-01 10.87 0.2360560 30-Nov-01 10.92 0.1970560 12-Dec-02 11.95 0.1970560 06-Nov-03 12.85 0.118



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J-3.11 MEPDG Input Summary: Arizona SPS-5 Test Section Example The following is a copy of the input files for the SPS-5-0504 test section run for predicting rut depths using version 9-30A of the MEPDG software and different transfer functions being used for NCHRP Project 9-30A.


Project: Arizona SPS-5 Project

General Information Description:SPS-5 project located west of Casa Grande, ARizona on I-8. Test Section 0504.

Design Life 15 yearsExisting pavement construction: June, 1978Pavement overlay construction: June, 1990Traffic open: June, 1990Type of design Flexible

Analysis Parameters


Location: SPS-5 ProjectProject ID: 504Section ID: Casa Grande, Arizona Principal Arterials - Interstate and Defense RoutesDate: 7/21/2008 Station/milepost format: Station/milepost begin: Station/milepost end: Traffic direction: East bound




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3340 2 50 95 60


1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00


2.8% 2.8% 2.8% 2.8% 2.8% 2.8% 2.8% 2.8% 2.8% 2.8%

18 10 12

1.62 0.39 0.00 0.00 2.00 0.00 0.00 0.00 1.02 0.99 0.00 0.00 1.00 0.26 0.83 0.00 2.38 0.67 0.00 0.00 1.13 1.93 0.00 0.00 1.19 1.09 0.89 0.00 4.29 0.26 0.06 0.00 3.52 1.14 0.06 0.00 2.15 2.13 0.35 0.00

8.5 12 120 51.6 49.2 49.2



Vehicle ClassMonth





Vehicle Class

Growth Rate

GrowthFunction





Quad Axle


Vehicle Class

Single Axle

Tandem Axle

Tridem Axle







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34.39 -112.25 5003 20

LoadTime(sec)

LowTemp.

-4ºF(1/psi)

Mid.Temp.14ºF

(1/psi)

HighTemp.32ºF

(1/psi) 1 2.98E-07 4.96E-07 6.92E-07 2 3.26E-07 5.75E-07 8.74E-07 5 3.67E-07 7.01E-07 1.19E-06 10 4.01E-07 8.14E-07 1.51E-06 20 4.39E-07 9.45E-07 1.9E-06 50 4.94E-07 1.15E-06 2.6E-06 100 5.41E-07 1.34E-06 3.28E-06

Climate icm file:

C:\DG2002\Projects\Casa Grande, Arizona.icm Latitude (degrees.minutes)Longitude (degrees.minutes)Elevation (ft)Depth of water table (ft)




Material type: Asphalt concreteLayer thickness (in): 5


Volumetric Properties as BuiltEffective binder content (%): 11Air voids (%): 7.5Total unit weight (pcf): 148




Asphalt BinderOption: Conventional viscosity gradeViscosity Grade AC 30A 10.6316 (correlated)VTS: -3.548 (correlated)




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Layer 2 -- Asphalt concrete (existing)Material type: Asphalt concrete (existing)Layer thickness (in): 5


Volumetric Properties as BuiltEffective binder content (%): 11Air voids (%): 7Total unit weight (pcf): 148



Asphalt MixCumulative % Retained 3/4 inch sieve: 12Cumulative % Retained 3/8 inch sieve: 35Cumulative % Retained #4 sieve: 58% Passing #200 sieve: 5




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Value 7.2555 1.3328 0.82422 117.4

Layer 3 -- Crushed stoneUnbound Material: Crushed stoneThickness(in): 17.6




#200 8.7#100 #80 12.9#60 #50 #40 20#30 #20 #16 #10 33.8#8 #4 44.7

3/8" 57.21/2" 63.13/4" 72.71" 78.8

1 1/2" 85.82" 91.6

2 1/2" 3"

3 1/2" 97.64" 97.6



Parametersabc

Hr.



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Value 5.8206 0.46207 3.8497 126.8

Layer 4 -- A-1-bUnbound Material: A-1-bThickness(in): 12


ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 1Liquid Limit (LL) 11Compacted Layer YesPassing #200 sieve (%): 13.4Passing #40 37.6Passing #4 sieve (%): 74.2D10(mm) 0.01398D20(mm) 0.1895D30(mm) 0.3103D60(mm) 1.582D90(mm) 17.77


#200 13.4#100 #80 20.8#60 #50 #40 37.6#30 #20 #16 #10 64#8 #4 74.2

3/8" 82.31/2" 85.83/4" 90.81" 93.6

1 1/2" 96.72" 98.4

2 1/2" 3"

3 1/2" 99.44" 99.4



Parametersabc

Hr.



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Value 5.8206 0.46207 3.8497 126.8

Layer 5 -- A-1-bUnbound Material: A-1-bThickness(in): Semi-infinite




#200 13.4#100 #80 20.8#60 #50 #40 37.6#30 #20 #16 #10 64#8 #4 74.2

3/8" 82.31/2" 85.83/4" 90.81" 93.6

1 1/2" 96.72" 98.4

2 1/2" 3"

3 1/2" 99.44" 99.4



Parametersabc

Hr.



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0.007566 3.9492 1.281

1 1

-3.35412 1.5606 0.4791

1.5

1 1

2.03 1.35

7 3.5 0 1000 1 1 0 6000

1 1 0 1000

40 0.4 0.008 0.015 40.8 0.575 0.0014 0.00825



k1k2k3



k1k2k3


0.24*POWER(RUT,0.8026)+0.001


k1



k1k2


Granular:k1

Fine-grain:k1










C4(HMA/PCC)




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J-4 COLORADO SPS-5 PROJECT


Functional Class: 1 Longitude: -103.208 AADTT (Both Directions): 1,960 in 1991;

3,550 in 2000 Soil Type: Lean or silty clay

mixed with sand and gravel; A-6

The Colorado SPS-5 project is located on Interstate Highway 70 in Lincoln County, Colorado. IH 70 is a four-lane divided highway. J-4.1 Construction History The original flexible pavement was built and opened to traffic in 1974. The flexible pavement

structure reported in the files consisted of the following: o 3 inches of a Class 7 emulsified asphalt treated base. o 5 inches of Grade E HMA (wearing surface was 1.5 inches)

The HMA overlay was placed in 1991 and opened to traffic in October 1991. The rehabilitation project included a rut level up course that was placed prior to placing the overlay for the sections included in the minimum surface preparation condition.

No construction issues were identified from the construction report, with the exception of two issues:

o A rut depth level-up course was placed on the control section. o The asphalt viscosities reported were high; exceeding 6,000 poises. The HMA

mixture was produced at elevated temperatures which may have aged the asphalt. No rehabilitation was applied to the overlaid pavement within the monitoring period for

measuring rut depths. However, a seal was applied in 1995 because raveling occurred along most of the test sections shortly after overlay placement. Cores were taken as part of a forensic investigation to determine the cause of the raveling. Stripping was noted in the cores.

J-4.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table CO-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B). Only four of the test sections were included for comparing the different transfer functions and test procedures: the sections without any milling. The sections without milling were used because the measured rut depth between the four sections without milling and the four with a milled surface are basically the same. The same asphalt concrete mixture was placed on all of the SPS-5 core test sections. Two supplemental test sections were included in this SPS-5 project and both were in the minimum surface preparation cells with a thicker HMA base layer and different gradation, defined a Grading G. Section 0559 included the same wearing surface placed over the other sections without RAP, while section 0560 included a polymer modified asphalt in the wearing surface without RAP.



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Table CO-1. Summary of Average Layer Thickness from LTPP Database Test Section Material Type and Thickness, inches

No. Surface

Condition Mixture

Type

HMA Overlay Existing Flexible Pavement HMA

Surface HMA Binder

Level-Up

HMA Emulsified

Asphalt Base 0502 No Milling RAP Mix 2.5 --- 1.3 5.4 2.5 0503 No Milling RAP Mix 2.0 2.3 0.9 5.2 2.5 0504 No Milling Virgin Mix 2.5 2.6 0.6 4.1 2.3 0505 No Milling Virgin Mix 2.5 --- 0.7 6.5 3.0 0506 Milled Surface Virgin Mix 1.7 2.0 --- 4.5 3.0 0507 Milled Surface Virgin Mix 4.8 2.0 --- 3.8 1.0 0508 Milled Surface RAP Mix 5.1 2.8 --- 2.3 1.6 0509 Milled Surface RAP Mix 2.3 2.0 --- 3.1 2.3 0559 No Milling Grading G 2.6 4.1 --- 6.5 3.7

0560 No Milling PMA,

Grading G 1.9

4.2 --- 5.7 2.5

J-4.3 Material Properties Reported during Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Those properties extracted from the LTPP database that were measured during construction and used to reconstitute the test specimens are summarized below.

Aggregate Properties for HMA Overlay Mixtures: Three aggregate types were included in the mixture design for all mixtures used within

this project. A crushed granite, manufactured sand, and natural sand. The natural sand consisted of 10 to 15 percent by weight of mix.

Fine Aggregate Angularity – Not reported in LTPP database, or on mixture design sheets (45).

Fine Aggregate bulk specific gravity – 2.65 but not on the mixture design sheets. Coarse Aggregate Angularity – Not reported in LTPP database, or on

mixture design sheets (90). Coarse Aggregate specific gravity – 2.653but not on mixture design sheets. Total Aggregate Absorption – Approximately 0.65 percent Hydrated Lime – Approximately 1 percent by mix weight. Aggregate Blend for the different layers or mixtures: The following percent passing

values are averages from the LTPP database.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #8 #16 #30 #200 Virgin Mix, Grading C

100 87 77 56 41 22 7

RAP Mix, Grading C

100 84 68 54 39 21 7

Mix, Grading G

100 75 60 45 32 17 5

PMA, Grading C

100 87 77 56 41 22 7

NOTE: Grading C was used for all of the lifts within the exception of the supplemental test sections 0559 and 0560 (see Table CO-1).



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Asphalt Properties for HMA Overlay Asphalt Specific Gravity, AC-20 with RAP – 1.048 Asphalt Specific Gravity, AC-20 without RAP – 1.045 Asphalt Specific Gravity, PMA (PG-70-28) – 1.101 Total asphalt content by weight: The total asphalt content and asphalt grade used within

each layer is tabulated below.

Mix Type Asphalt Content for Mixture Type

In Place Value, Grading C

Design Value, Grading C

Design Value, Grading G

Virgin Mix, AC-20 4.7 4.5 4.7 RAP Mix, AC-20 4.1 4.2 --- Virgin Mix, PMA PG70-28 --- 4.0 ---

HMA Overlay Mixture Properties Hydrated lime was used as an anti-strip additive at a rate of 1.0 percent; all TSR values were significantly greater than the required value of 80 percent. The following summarizes the HMA volumetric properties for each of the mixtures included in the SPS-5 experiment.

HMA Mix Property

Grading C, Virgin Mix

Grading C, RAP Mix

Grading G, Virgin Mix

Grading C, PMA

Max. Specific Gravity, Design 2.487 2.509 2.493 2.521 Max. Specific Gravity, LTPP 2.506 2.516 --- --- Average Air Voids 7.90 8.86 --- ---

As tabulated, the maximum specific gravities reported by LTPP are significantly different than recorded on the mixture design sheets. More importantly, the air voids calculated for the HMA overlay for the mixtures with and without RAP are relatively high. The mixtures with the RAP had the higher air voids at construction.

Existing HMA Layer/Mixture Some of the asphalt and mixture properties were unavailable within the LTPP database, so the properties from the virgin mixtures were assumed for the existing HMA layers. None of the properties needed for the emulsified asphalt stabilized base were unavailable from the LTPP database, so that layer was combined with the existing HMA layer. The following were extracted from the LTPP database for the existing HMA surface layer. Asphalt Specific Gravity – 1.101 Asphalt Content by Weight – 4.6 Maximum Specific Gravity – 2.4203 Air Voids – 2.2 Aggregate Blend for the Existing HMA Mixture:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Passing, % 100 100 100 80 66 52 39 15 8 6.4

J-4.4 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section report. The maximum rut depths measured along the individual test sections after overlay placement varied from 0.118 to 0.315 inches—low levels of rutting.



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Figures CO-1 and CO-2 show the measured rut depths over time before and after overlay placement for the test sections with and without RAP, respectively. The SPS-5 project exhibited high levels of rutting prior to overlay placement and was the reason for rehabilitation. The maximum rut depth measured along the segment of IH-70 varied from 0.8 inches to over an inch.

Figure CO-1. Rut Depths Measured Over Time for the SPS-5 Core Test Sections with RAP

Mixtures

Figure CO-2. Rut Depths Measured Over Time for the SPS-5 Core Test Sections without

RAP Mixtures (Virgin Mixtures)



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Figure CO-3 shows the effect of HMA overlay thickness on the maximum rut depth measured along each of the SPS-5 test sections. As shown, the rut depths are low and HMA overlay thickness has no effect on the rut depths for this SPS-5 project. There is a difference between the sections with and without RAP; the test sections without RAP in the mixtures (defined as virgin mixtures) exhibit slightly higher rut depths. The following lists the average maximum rut depths measured on the sections with the different conditions of the existing flexible pavement. Statistical Parameter

Grading C, RAP Mixtures

Grading C, Virgin Mixtures

Grading G, Virgin Mixture

Grading C, PMA Mixture

Mean Max. Rut Depth, in.

0.207 0.266 0.197 0.236

Standard Deviation, in.

0.0378 0.0591 --- ---

Coefficient of Variation, %

18.3 22.2 --- ---

The supplemental test section with the larger aggregate exhibited about the same rut depths as for the test sections with RAP, as summarized above. The supplemental test section with the polymer modified asphalt exhibited less rutting than the mixtures without RAP.

Figure CO-3. Effect of HMA Overlay Thickness on Maximum Rut Depth

In summary, these test sections have exhibited minimal rutting. These rut depths are so low it would be difficult to determine the amount of rutting within the different layers considering the variation in thickness profiles caused by the paver. Thus, this project was not identified as a candidate for the forensic investigations under NCHRP Project 9-30A. Based on an analysis of the measured rut depths, all measurable rutting has probably occurred

in the HMA overlay, as well as in the existing HMA. As shown in Figures CO-1 and CO-2, excessive rutting was one of the reasons for the overlay; the maximum rut depths prior to overlay were in excess of 0.8 inches. Thus, it is expected that some of the rutting measured after overlay probably exhibited in the existing HMA layers, especially since stripping was



J - 55

mentioned in some of the coring logs. Although the higher viscosities measured in the RAP and virgin mixtures should reduce the rut depth growth rates, the moisture damage will increase that growth rates. Both conditions should be taken into consideration in determining and using the field-derived plastic deformation coefficients relative to the other test sections selected for this study.

J-4.5 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. Figure CO-4 presents the dynamic modulus values measured on the HMA overlay, which were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E.

Figure CO-4. Dynamic Modulus Values Measured on the HMA Mixture without RAP

J.4.6 Rut Depth Predictions Using the Global Transfer Function Coefficients Figures CO-5 and CO-6 include a comparison of the predicted and measured rut depths for the SPS-5 sections with and without RAP, respectively. For these solutions, only one set of plastic deformation coefficients were used for all HMA layers to be consistent with the global transfer function. Sections 0507 and 0508 have the thicker overlays (around 7 inches) while sections 0502 and 0505 have much thinner overlays (around 3.5 inches including the rut depth level up layer). The Asphalt Institute transfer function significantly over predicts the measured rut depths. Similarly, the WesTrack transfer function over predicts the measured rut depth, but the slope or increase in rutting over time more closely simulates the measured rut depth growth rate. Conversely, the Verstraeten transfer function is the better simulation of the measured rut depth, while the MEPDG transfer function predicts ruts depths lower than the measured values. The asphalt concrete mix dependent coefficients of the NCHRP project 1-40B transfer function also under predicts the measured values.



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Figure CO-5. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Global Plastic Deformation Coefficients for each Transfer Function for SPS-5 Sections 0502

and 0508 (RAP Mixtures)



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Figure CO-6. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the

Global Plastic Deformation Coefficients for each Transfer Function for Sections 0505 and 0507 (Virgin Mixtures)

J.4.7 Field-Derived Coefficients of the Transfer Functions The measured rut depths were used to determine the coefficients of each transfer function to eliminate the bias and reduce the standard error of the estimate to the lowest possible value for each transfer function. Figure CO-7 and CO-8 include examples of the predicted and measured rut depths for each transfer function using the field matched or field-derived plastic strain coefficients for each transfer function. As shown, each transfer function can accurately predict the measured rut depths. Similar results were obtained for the other test sections of this SPS-5 project. Table CO-2 summarizes the field-derived coefficients of each transfer function and test section. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.



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Figure CO-7. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0508 (RAP Mixtures)



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Figure CO-8. Examples of Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0505 and 0507

(Virgin Mixture)



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Table CO-2. Field-Derived Slope and Intercept

Coefficient Test

Section Kaloush

NCHRP 1-40B

Modified Leahy


Slope All 0.315 0.315 0.315 0.315 0.315 Intercept 0502 -2.17 -2.47 -0.95 100 2.20

0503 -2.17 -2.45 -0.85 95 4.5 0504 -2.08 -2.45 -0.85 95 4.5 0505 -2.08 -2.25 -0.95 100 2.20 0506 -2.17 -2.27 -0.85 95 4.0 0507 -1.935 -2.47 -0.872 87.5 7.14 0508 -2.15 -2.27 -0.943 90 5.31 0509 -2.17 -2.25 -0.85 95 4.0



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RAP Mix Virgin Mix Existing HMA



Air Voids, % Va 8.86 7.90 2.24











Log Kr1 2.40 2.39 2.63





Kr1 Value 251.18864 245.47089 426.5795188Absorbed Asphalt by Weight, % 0.75 0.55 0.5kr1 Log Value 9.2441378 10.164884 8.801503728

Colorado SPS-5 Project




J - 62



Section Construction No. Survey Date Age, years Rut Depth, in. Section Construction No. Survey Date Age, years Rut Depth, in.0502 1 11-Dec-90 -0.82 0.827 0507 1 11-Dec-90 -0.82 0.5910502 1 01-May-91 -0.44 0.787 0507 1 03-May-91 -0.43 1.2600502 1 19-Aug-91 -0.14 0.315 0507 1 19-Aug-91 -0.14 0.8270502 2 27-Feb-92 0.39 0.118 0507 2 27-Feb-92 0.39 0.0790502 2 25-Apr-96 4.55 0.157 0507 2 25-Apr-96 4.55 0.2760502 3 29-Jul-98 6.81 0.197 0507 3 31-Jul-98 6.82 0.2760502 3 30-Aug-99 7.90 0.236 0507 3 31-Aug-99 7.90 0.3150502 3 10-Oct-99 8.01 0.197 0507 3 10-Oct-99 8.01 0.276

0503 1 11-Dec-90 -0.82 0.709 0508 1 11-Dec-90 -0.82 0.7870503 1 02-May-91 -0.44 1.142 0508 1 02-May-91 -0.44 1.1420503 1 19-Aug-91 -0.14 0.315 0508 1 19-Aug-91 -0.14 0.7480503 2 27-Feb-92 0.39 0.079 0508 2 27-Feb-92 0.39 0.1180503 2 25-Apr-96 4.55 0.157 0508 2 25-Apr-96 4.55 0.2360503 3 29-Jul-98 6.81 0.157 0508 3 30-Jul-98 6.81 0.1970503 3 30-Aug-99 7.90 0.157 0508 3 30-Aug-99 7.90 0.1970503 3 10-Oct-99 8.01 0.157 0508 3 10-Oct-99 8.01 0.157

0504 1 11-Dec-90 -0.82 0.787 0509 1 11-Dec-90 -0.82 0.8270504 1 02-May-91 -0.44 0.906 0509 1 01-May-91 -0.44 1.1420504 1 19-Aug-91 -0.14 0.276 0509 1 19-Aug-91 -0.14 0.9060504 2 27-Feb-92 0.39 0.039 0509 2 27-Feb-92 0.39 0.0390504 2 25-Apr-96 4.55 0.157 0509 2 25-Apr-96 4.55 0.1970504 3 30-Jul-98 6.81 0.118 0509 3 29-Jul-98 6.81 0.1180504 3 31-Aug-99 7.90 0.118 0509 3 30-Aug-99 7.90 0.1180504 3 10-Oct-99 8.01 0.197 0509 3 10-Oct-99 8.01 0.157

0505 1 11-Dec-90 -0.82 0.748 0559 1 03-May-91 -0.43 0.9840505 1 03-May-91 -0.43 1.142 0559 2 25-Apr-96 4.55 0.1180505 1 19-Aug-91 -0.14 0.276 0559 3 31-Jul-98 6.82 0.1970505 2 27-Feb-92 0.39 0.079 0559 3 01-Sep-99 7.90 0.1970505 2 25-Apr-96 4.55 0.157 0559 3 10-Oct-99 8.01 0.1570505 3 31-Jul-98 6.82 0.1970505 3 31-Aug-99 7.90 0.2360505 3 10-Oct-99 8.01 0.236

0506 1 11-Dec-90 -0.82 0.551 0560 1 03-May-91 -0.43 1.1020506 1 03-May-91 -0.43 0.906 0560 2 25-Apr-96 4.55 0.1570506 1 19-Aug-91 -0.14 0.984 0560 3 29-Jul-98 6.81 0.1180506 2 27-Feb-92 0.39 0.118 0560 3 01-Sep-99 7.90 0.1570506 2 25-Apr-96 4.55 0.197 0560 3 10-Oct-99 8.01 0.2360506 3 31-Jul-98 6.82 0.2360506 3 31-Aug-99 7.90 0.2760506 3 10-Oct-99 8.01 0.315



J - 63

J-5 MISSISSIPPI SPS-5 PRPOJECT


Functional Class: 1 Longitude: -90.04 AADTT (Both Directions): 1,950 to 3,200 Soil Type: Lean Clay with Sand to

Sandy Lean Clay; A-6 The Mississippi SPS-5 project was included in the NCHRP 9-30A experimental matrix for three reasons: (1) sufficient materials were available in the MRL, (2) excessive rutting occurred on all test sections in comparison to other SPS-5 projects, and (3) this project is the companion to the Mississippi SPS-9 and other PMA experimental research projects. The Mississippi SPS-5 project is located just north of Canton, Mississippi on Interstate Highway 55 in the northbound traffic lane in Yazoo County. Interstate 55 is a four-lane divided highway. Truck traffic data were supplied by the Mississippi DOT for this segment of I-55 and included the average annual daily truck traffic, normalized truck volume distribution, normalized axle load distributions, monthly truck volume distribution factors, and the number of axles per truck. The normalized truck volume distribution factors are presented in Figure MS-1 in comparison to the average values included in the LTPP database. As shown, the normalized volume distributions are similar. The values supplied by the Mississippi DOT were used because these were then consistent with the other truck traffic input values provided for this segment of roadway. The MEDPG input summary included at the end of this Test Section Report provides all of the truck traffic inputs that were used in the simulation or for predicting rut depths over time.

Figure MS-1 Normalized Truck Volume Distribution Factors for the Mississippi SPS-5 Project

0.0010.0020.00

30.0040.0050.0060.00

70.0080.00

4 5 6 7 8 9 10 11 12 13

Vehicle Classification

Normalized Vehicle Volume

Distribution, %

LTPP Database Mississippi DOT, Planning Dept.



J - 64

J-5.1 Construction History The existing flexible pavement was built in 1974 and exhibited high levels of rutting. Figure

MS-2 shows the rut depths prior to the HMA overlay and the increase in rut depths over time for two of the SPS-5 sections. The average rut depths for all sections prior to overlay generally exceeded 0.75 inches.

Figure MS-2. Rut Depth Time-Series Data from LTPP Showing the Rutting Prior to Overlay The HMA overlay was placed in 1990 and opened to traffic in September 1990. This project took a long time to construct, because of the numerous production plant

breakdowns that occurred. Maintaining a consistent mixture during construction was attributed to the plant breakdowns.

No maintenance or rehabilitation activities were placed on this SPS-5 project during the monitoring period for measuring rut depths.

The SPS-5 project was taken out of service or de-assigned from the LTPP SPS-5 experiment in August 1999, because of excessive rutting. The excessive rutting was caused by moisture damage and stripping.

J-5.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the HMA volumetric data at the time of construction. Table MS-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B). All other layer properties needed to execute the MEPDG were also extracted from the LTPP database or obtained from Mississippi DOT construction records and other research reports. Most of the soils at this site were classified as an A-6 soil, with the exception of a few of the test sections that were classified as an A-7-6 soil. Repeated load resilient modulus test results for the subgrade soil were available for this SPSP-5 project and are presented in Figure MS-3. The resilient modulus for this SPS-5 project varies from 6,000 to nearly 20,000 psi. Most of the test sections have a resilient modulus of at the time of construction of 9,000 psi. The two samples with the low resilient modulus values (refer to figure MS-2) that do not vary with bulk stress were

0

0.2

0.4

0.6

0.8

1

-2.0 0.0 2.0 4.0 6.0 8.0 10.0

Age, years

Ave

rag

e M

ax. R

ut

Dep

th,

in.

0503, RAP Mix 0504, Virgin Mix

SPS-5 HMA overlay placed in 1990.



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believed to be an anomaly in the test results and were excluded from determining the resilient modulus at the time of overlay placement.

Table MS-1. Summary of Average Layer Thickness from LTPP Database

Test Section

Layer Type and Thickness, in. HMA Overlay Existing Pavement

Mix Type Wearing Surface

HMA Binder & Level Up

HMA Surface &

FC

HMA Binder ATB

Lime Treated

Soil 0502 RAP Mix 2.1 --- 0.5 3.5 7.1 3.3 0503 RAP Mix 2.4 2.2 1.1 3.5 7.1 3.3 0504 Virgin Mix 1.9 3.1 1.7 2.6 8.6 6.0 0505 Virgin Mix 2.0 --- 1.8 2.6 7.8 4.5

0506 Virgin

Mix/Mill 1.8 --- 0.0

1.3 7.8 4.5

0507 Virgin

Mix/Mill 1.9 3.1 0.1

1.3 7.3 9.2

0508 RAP Mix/Mill 2.0 2.8 0.0 1.8 7.7 --- 0509 RAP Mix/Mill 2.3 1.5 0.0 0.4 7.6 4.0 0560 Interlayer/Mill 1.5 1.5 0.3 2.9 8.0 6.0

NOTES: 1. FC; friction course, which was combined with the existing HMA surface thickness. 2. Asphalt Treated Base. 3. For the supplemental section 0560, an interlayer or fabric and slurry seal was placed between the

existing milled pavement surface and HMA overlay; virgin mixture. In addition, EVERCALC was used to back-calculate the elastic layered modulus values from deflection basins measured with the Falling Weight Deflectometer (FWD). A rigid layer was simulated in the back-calculation process. The computed thickness of the subgrade above the rigid layer varies from about 200 to 600 inches. The back-calculated elastic layer modulus for the subgrade was found to vary from 17,000 to nearly 30,000 psi. The ratio between the laboratory equivalent resilient modulus and back-calculated modulus for the subgrade is approximately 0.4, which is consistent with the C-factor determined from LTPP for flexible pavement structures with a lime-stabilized subgrade. Figure MS-4 compares the resilient modulus values to the back-calculated modulus values for the subgrade just after overlay placement. The resilient modulus values predicted by the MEPDG over time are reasonably close to the back-calculated elastic layered modulus values adjusted to laboratory values—in accordance with the C-factors. The resilient modulus value for the subgrade measured during overlay placement was entered in the MEPDG. The elastic layered modulus was back-calculated for the other pavement layers, excluding the lime-stabilized subgrade layer because it is too thin. The existing wearing surface and binder layer were combined while the HMA overlay and asphalt treated base (ATB) layers were considered separate layers within the back-calculation process. Figure MS-5 compares the dynamic modulus values calculated with time at the mid-depth of the overlay and existing pavement with the MEPDG to those back-calculated with EVERCALC. As expected, there is extensive dispersion between the values. The back-calculated values are much lower than the measured values for all layers, with the exception of the existing surface and binder layers. Figure MS-6 shows the ratio of back-calculated to laboratory or MEPDG modulus



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values. Ratios less than unity or 1.0 suggest damage of that layer, especially after 1996. This damage is believed to be related to moisture damage for this LTPP project, both in the overlay and existing HMA mixtures.

Figure MS-3. Resilient Modulus Test Extracted from the LTPP Database

Figure MS-4. Comparison of Resilient Modulus to Elastic Layered Modulus Back-Calculated

with EVERCALC for the Subgrade

0

5

10

15

20

25

5 10 15 20 25 30

Bulk Stress, psi

Res

ilien

t M

od

ulu

s, k

si Section 0501

Section 0503

Section 0504

Section 0506

Section 0507

Section 0508

Section 0509

Section 0560

Poly. (Section 0506)

Poly. (Section 0503)

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Resilient Modulus, Laboratory, ksi

Bac

k-C

alcu

late

d E

last

ic M

od

ulu

s,

ksi

Mississippi SPS-5 DataBetween Lab and Back-Calculated ModulusValues fo Subgrade

Relationship for SoilsBelow a Stabilized Layer

Relationship for SoilsBelow Full-DepthPavement without aStabilized Layer

Relationship for Soilsbelow ConventionalFlexible Pavement



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Figure MS-5. Comparison of Dynamic Modulus Values Predicted with the MEPDG to the Back-

Calculated Elastic Layered Modulus Values J-5.3 HMA Material Properties Reported During Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Only the bulk specific gravities measured during construction were recorded in the LTPP database. All of the other properties had to be obtained from other construction records provided by the Department and from the mixture design sheets that were also provided by the Mississippi DOT. The following properties were used to reconstitute the test specimens for the production test program.

100

1000

10000

100 1000 10000

Laboratory Measured Dynamic Modulus Values, ksi

Bac

k-C

alcu

late

d E

last

ic

Mo

du

lus

Val

ues

, ks

i

Thin Overlay Thin Overlay Thick Overlay Line of Equality

Region with no damage, as estimated by the FWD.

Region with damage

(moisture damage), as estimated by

the FWD.

10

100

1000

10000

100 1000 10000

Laboratory Measured Dynamic Modulus, HMA Base (MEPDG), ksi

Bac

k-C

alcu

late

d M

od

ulu

s V

alu

es,

HM

A B

ase,

ksi

Asphalt Treated Base HMA Binder Layer Line of Equality



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Figure MS-6. Damage Estimate from FWD Measurements for the Overlay and Existing HMA

Layers

Aggregate Properties for HMA Overlay Mixtures: Type of new aggregate included in the mixture design for both the RAP and virgin

mixtures for the binder and surface layers was crushed gravel and limestone, and coarse field sand. The following lists the aggregate percentages used to establish the job mix formula for all mixtures used within this SPS-5 project.

Layer Aggregate Type Aggregate Percentages

RAP Mix Virgin Mix

Binder & Leveling; BC-

1

Recycled HMA 30 --- -3/4 Crushed Gravel 60 80 Crushed Limestone 5 10 Coarse Field Sand 5 10

Wearing Surface; SC-1

Recycled HMA 30 --- Crushed Gravel 30 60 #89 Limestone 15 10 Ag. Limestone 5 10 Coarse Field Sand 20 20

Aggregate Angularity:

o Fine Aggregate Angularity – Not reported in the LTPP database or on the mixture design sheets for any mixture; but, field sand used and baghouse fines returned to the mix. Thus, FAA < 45.

o Coarse Aggregate Angularity – 80 percent crushed with two faces. Bulk specific gravity:

o Fine aggregate from LTPP records – Not reported Value from mixture design records – 2.635

o Coarse aggregate from LTPP records – Not reported Value from mixture design records – 2.522

Aggregate Absorption: o Fine aggregate from LTPP records – Not reported

0.01

0.1

1

10

100

May-90 Sep-91 Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99

Date

Rat

io:

Bac

k-C

alcu

late

d/L

ab

Mo

du

lus

(<1

= D

amag

e),

ksi

Overlay Binder Layer ATB Layer Poly. (Overlay)



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Value from mixture design sheets – 0.30 o Coarse aggregate from LTPP records – Not reported

Value from mixture design sheets – 1.86 o Combined aggregate blend from mix design – 1.43 from mix design.

Mixture #1—RAP Mixture and Test Sections – Binder Mixture: The mixture design sheets provided most of the information to determine the in place properties of the RAP mixture during construction. Few mixture properties were recorded in the LTPP database—in fact, only bulk specific gravities of the different mixtures were measured during construction and included in the LTPP database. The following values were used to reconstitute the mixtures in the laboratory for production testing. Asphalt grade used in RAP mix – AC-30 Asphalt Specific Gravity – Not recorded

o The asphalt specific gravity was not included on the mixture design sheets but obtained from other Department records – 1.06.

Anti-Strip, Perma Tac Plus o Binder mix; 0.3 percent by weight of asphalt o Surface mix; 0.5 percent by weight of asphalt

Amount of RAP used in binder and surface – 30 percent Bulk specific gravity of aggregate blend – 2.528 for the binder layer and 2.495 for the

surface mix. o The bulk specific gravity of the aggregate blend was reported on the mixture

design sheet as 2.550 for the binder mixture and 2.587 for the wearing surface mixture.

Effective specific gravity of aggregate – 2.618 for the binder layer and 2.582 for the surface layer.

Total asphalt content by weight – 5.00 for the binder mix and 5.65 for the wearing surface mix at 4.0 percent air voids.

o Binder Mixture: The target asphalt content to be added was 3.41 percent; the amount of asphalt in the RAP material was 5.28 percent.

o Surface Mixture: The target asphalt content to be added was 3.95 percent; the amount of asphalt in the RAP material was 5.67 percent.

Maximum Specific Gravity of RAP mix – Not recorded. o The maximum specific gravity at the target asphalt content reported on the

mixture design sheet was 2.396 for the binder mix and 2.417 for the wearing surface.

Voids in Mineral Aggregate – 14.0 for the surface layer and 13.3 for the binder layer. o The VMA at the target asphalt content from the mixture design sheet was 14.2

percent for the binder mix and 15.4 percent for the wearing surface mixture. Average Air Voids at construction; the binder layer was used to reconstitute the test

specimens for laboratory testing: o Target asphalt content selected at – 4.0 percent. o Binder layer of overlay – 3.4 percent o Wearing surface overlay – 4.61 percent

Aggregate Blend for the 19 mm PMS, Grade B Special RAP Mixture; the following percent passing values are averages from the Department’s database in comparison to the values taken from the Job Mix Formula (JMF).



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Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #8 #30 #50 #200 JMF Surface 100 100 100 100 96 67 50 30 13 5.1 JMB Binder 100 100 100 92 80 52 36 21.1 12.4 5.5 Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 DOT 100 100 100 94 86 58.6 34.4 13.5 6.3 4.3

Mixture #2—Virgin Mixture and Test Sections: Asphalt grade used in virgin mix – AC-30 Asphalt Specific Gravity – Not recorded

o The asphalt specific gravity was not included on the mixture design sheets, but was obtained from other construction recorded provided by the Department and was 1.02.

o The asphalt specific gravity measured on samples recovered from the MRL was 1.038.

Anti-Strip; Perma Tac Plus o Surface mix; 0.3 percent by weight of asphalt. o Binder mix; 0.5 percent by weight of asphalt.

Bulk specific gravity of aggregate blend – 2.531 for the surface layer and 2.499 for the binder layer.

o The bulk specific gravity of aggregate used in mixture design was recorded on the mixture design sheets for the surface mix as 2.573 and 2.536 for the binder layer.

Effective specific gravity of aggregate – 2.624 for the surface mix and 2.589 for the binder layer.

Total asphalt content by weight – 5.6 for the binder mix and 5.9 for the surface mix.

o The target asphalt contents were determined at 4.0 percent air voids. Maximum Specific Gravity –

o The maximum specific gravity reported on the mix design sheets at the target asphalt content was 2.401 for the surface mix and 2.384 for the binder mix.

Voids in Mineral Aggregate of virgin mix – 15.8 for the surface layer and 12.8 for the binder layer.

o The VMA at the target asphalt content from the mixture design sheet was 14.8 percent for the binder mix and 15.7 percent for the surface mix.

Average Air Voids at construction; the binder mix was used to reconstitute the test specimens for laboratory testing:

o Target asphalt content selected at – 4.0 percent. o Binder Mix of overlay – 3.7 percent o Surface mix of overlay – 5.71 percent

Aggregate Blend for the 19 mm PMS, Grade B Mixture; the following percent passing values are averages from the Department’s database in comparison to the values taken from the Job Mix Formula (JMF).

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #8 #30 #50 #200 JMF Surface 100 100 100 100 96 65 47 25.9 10.9 4.6 JMF Binder 100 100 100 88 73 45 32 17.7 8.9 4.3 Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 DOT 100 100 100 95 85 56.1 34 13.7 5.9 3.8



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Existing HMA Layer/Mixture: Asphalt Specific Gravity – 1.046 Asphalt Content by Weight – 5.8 for the surface, 4.3 for the binder mix, and

4.5 for the ATB base. Maximum Specific Gravity – Not provided Air Voids – 4.94 for the surface mixture; 3.28 for the

binder layer; and 5.49 for the HMA base or ATB layer.

Aggregate Blend for the Three Layers/Mixtures, percent passing: Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF Surface 100 100 100 100 95 77 49 23 11 6.0 JMF Binder 100 100 100 93 80 55 43 25 12 6.5 JMF Base 100 94 75 54 47 28 11 6.0

J-5.4 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. Figure MS-7 presents the dynamic modulus values measured on the HMA overlay without RAP, which were entered in the MEPDG for predicting rut depth over time. J-5.5 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section report. The maximum rut depths measured along the individual test sections varied from 0.41 inches (virgin mixture) to 0.86 inches (virgin mixture)—a significant difference between the test sections. Figure MS-8 shows the measured rut depths as a function of time for all test sections within the SPS-5 project. As shown, mixture type (RAP versus virgin mixes) was found to have a minor effect on the magnitude of the rut depths—the sections with the virgin mixture exhibited slightly greater rut depths, but there is no statistical difference in measured rut depths between test sections with and without RAP in the HMA overlay. The following lists the average maximum rut depths measured on the sections with and without RAP in the HMA overlays.




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Figure MS-7. Dynamic Modulus Values Measured on the HMA Overlay

Figure MS-8. Rut Depths Measured Over Time for the SPS-5 Test Sections

Figure MS-9 shows the effect of HMA overlay thickness and mixture type on the maximum rut depth measured along each of the SPS-5 test sections. As shown, the rut depths increase with increasing HMA overlay thickness. In addition, the sections without any RAP in the mixture exhibit slightly more rutting than sections with RAP, when considering differences in the HMA overlay thickness. The increase in rutting with HMA thickness was expected because of the stripping or moisture damage exhibited on this project.

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t D

epth

, in

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0502, RAP

0503, RAP

0508, RAP

0509, RAP

0504, Virgin

0505, Virgin

0506, Virgin

0507, Virgin

0560, Virgin

10.0

100.0

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Test Temperature, F

Dyn

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Mo

du

lus,

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Freq = 0.1 Hz

Freq = 0.5 Hz

Freq = 1 Hz

Freq = 5 Hz

Freq = 10 Hz

Freq = 25 Hz



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Figure MS-9. Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth J-5.6 Forensic Investigation of Mississippi SPS-5 Project Although the rut depths do not appear to be highly related to HMA mixture type, the Mississippi SPS-5 project was initially identified as a potential candidate for a forensic investigation, because of the higher values measured along this project and the effect of thickness on the measured rut depth. In addition, the rut depths were found to increase at a higher rate than for most of the other SPS-5 projects. The increase in rutting over time for this project was higher than any other HMA mixture tested within this study (NCHRP Project 9-30A). This SPS-5 project, however, was taken out of service in the latter part of 1999, when it was rehabilitated for safety reasons—excessive rutting. A forensic investigation of that SPS-5 project was not completed within the LTPP program. Mr. Gaylon Baumgardner with Ergon and Mr. Bill Bartis with the Mississippi DOT were contacted to determine if any cores from this HMA overlay had been retained, as a result of the SPS-9 project that was built along this same section of I-55 and at the same time. It appears that any available cores were not maintained in a controlled environment. Although an anti-strip agent was included in the HMA mixture, it is believed that stripping or moisture damage is a reason for these higher rut depths. Stripping or moisture damage cannot be directly simulated in the MEPDG. This hypothesis is supported by the back-calculated elastic modulus values for the overlay and existing HMA layers. J-5.7 Rut Depth Predictions Using the Global Transfer Function Coefficients Figure MS-10 provides an example comparing the predicted rut depths with the different transfer functions and measured rut depths with time for the thinner and thicker HMA overlays for two test sections that exclude RAP in the mixtures (test sections 0504 and 0505). Only one set of plastic deformation coefficients were used for all HMA layers to be consistent with the global transfer function. The overlay thickness placed on section 0504 is 5.0 inches which had the higher rut depths, while the overlay thickness for section 0505 is 2.0 inches. As shown, there is a significant bias for the different transfer functions which is thickness dependent. For the thicker section (0504), all transfer functions under predicted the measured rutting.

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rag

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ax.

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t D

epth

, in

.

RAP Mixtures

Virgin Mixtures

Expon. (RAPMixtures)

Expon. (VirginMixtures)



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Figure MS-10. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Global Plastic Deformation Coefficients for each Transfer Function for SPS-5 Sections

0504 and 0505 (Mixtures without RAP) Figure MS-11 provides a comparison of the predicted and measured rut depths for each transfer function using the global plastic deformation coefficients for two of the test section with RAP in the mixtures. Section 0502 has an overlay thickness of 2.1 inches, while the overlay thickness for section 0503 is 4.6 inches. Section 0502 is the thinner and has the lower rut depth, similar to the sections without RAP in the mixtures. The Verstraeten and MEPDG transfer functions had the least bias or residual error in predicting the measured rut depths for the thinner section (0502), but the predicted rut depth growth rates were lower than the measured values. The Asphalt Institute transfer function had the least bias for the thicker section (0503) and reasonably predicted the rut depth growth rate. The other rut depth transfer functions significantly under predicted the measured rutting. The predicted rut depth growth rate was also much lower than the measured values. The asphalt concrete mix dependent coefficients of the NCHRP project 1-40B transfer function also under predicted the measured values.



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In summary, none of the transfer functions consistently predicted the rutting of this project using the global plastic deformation coefficients; probably a result of the moisture damage and stripping reported in the HMA mixtures.

Figure MS-11. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Global Plastic Deformation Coefficients for each Transfer Function for Sections 0502

and 0503 (Mixtures with RAP)



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J.5.8 Field-Derived Coefficients of the Transfer Functions The measured rut depths were used to determine the coefficients of each transfer function to eliminate the bias and reduce the standard error of the estimate to the lowest possible value for each transfer function. The slopes or exponent for the traffic term were found to be constant for all of the overlays and existing HMA layers. The following lists the values used for all of the transfer functions; except for the coefficient determined from the NCHRP 1-40B adjustment factors which are mixture dependent.

HMA Overlay without RAP

HMA Overlay with RAP

Existing HMA Layers

Slope or Exponent of the Traffic Term

0.55 0.55 0.45

As listed, the slopes or exponents of the traffic term were found to be very high and were significantly greater than the value determined from the NCHRP 1-40B mixture adjustment process (0.39); probably caused by the stripping reported in the HMA layers. Figure MS-12 and MS-13 include examples of the predicted and measured rut depths for each transfer function using the field matched or field-derived plastic strain coefficients for each transfer function, excluding the NCHRP 1-40B mixture adjustment procedure. As shown, each transfer function accurately predicted the measured rut depths. Similar results were obtained for the other test sections of this SPS-5 project. Table MS-2 summarizes the field-derived coefficients of each transfer function and test section. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.

Table MS-2. Field-Derived Slope and Intercept

Coefficient Test

Section Kaloush

NCHRP 1-40B

Modified Leahy


Slope All 0.55 0.39 0.55 0.55 0.55 Intercept 0502 -3.38 -2.466 -1.57 30 0.61

0503 -3.65 -2.466 -1.57 200 0.55 0504 -3.09 -2.466 -1.68 84 0.61 0505 -3.33 -2.466 -1.57 187 0.44 0506 -3.70 -2.466 -1.57 200 0.50 0507 -3.10 -2.466 -1.64 90 0.17 0508 -3.10 -2.466 -1.64 90 0.17 0509 -3.65 -2.466 -1.55 190 0.55



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Figure MS-12. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0504 and 0505 (Mixtures

without RAP)



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Figure MS-13. Examples of Predicted versus Measured Rut Depths using MEPDG Version

9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0503 (Mixtures with RAP)



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Surface Binder Surface Binder Surface Binder ATB

Bulk Specific Gravity Gmb 2.3049 2.2855 2.2638 2.3089 2.291 2.314 2.221

Maximum Specific Gravity Gmm 2.417 2.396 2.401 2.384 2.41 2.39 2.35

Air Voids, % Va 4.64 4.61 5.71 3.15 4.94 3.18 5.49

Air Voids for Target Asphalt Content, % Va(design) 4.00 4.00 4.00 4.00 4.00 4.00 4.00

Total Asphalt Content by Weight, % Pb 5.65 5.40 5.90 5.60 5.80 4.30 4.50

Optimum/Saturation Asphalt Content, % Pb(0pt) 5.50 5.30 5.70 5.50 5.50 4.00 4.20

Aggregate Effective Specific Gravity Gse 2.618 2.582 2.624 2.589 2.620 2.536 2.497

Bulk Specific Gravity of Aggregate Blend Gsb 2.528 2.495 2.531 2.499 2.525 2.447 2.410

Effective Asphalt Content by Volume, % Vbe 9.352 8.726 10.108 9.621 9.609 6.337 6.513

Voids in Mineral Aggregate, % VMA 14.0 13.3 15.8 12.8 14.5 9.5 12.0Voids Filled with Asphalt, % VFA 66.8 65.4 63.9 75.3 66.1 66.6 54.3

Gradation Factor (GI Term) Kr3 0.80 0.80 0.80 0.80 0.80 0.80 0.80

Fine Aggregate Factor Findex 1.00 1.00 1.00 1.00 1.00 1.00 1.00

Coarse Aggregate Factor Cindex 0.95 0.95 0.95 0.95 0.95 0.95 1.00

Log Kr1 2.48 2.42 2.40 2.77 2.43 2.47 2.36

Rut Depth Coefficient kr1 -2.466 -2.558 -2.465 -2.251 -2.490 -2.732 -2.706

Temperature Exponent kr2 1.591 1.573 1.692 1.428 1.670 1.532 1.841

Traffic Loadings Exponent kr3 0.394 0.391 0.397 0.390 0.404 0.412 0.411

Asphalt Specific Gravity Gb 1.06 1.06 1.02 1.02 1.046 1.046 1.046Kr1 Value 301.995172 263.026799 251.1886432 588.8437 269.1535 295.1209 229.0868Absorbed Asphalt by Weight, % 1.43 1.43 1.43 1.43 1.5 1.5 1.5kr1 Log Value 9.60642787 7.78123923 9.633245504 15.753 9.090231 5.213581 5.530042

DETERMINATION OF NCHRP 1-40B MIXTURE ADJUSTMENT FACTORS FOR PREDICTING RUTTING

Mississippi SPS-5 Project

Existing LayersVirgin MixtureRAP MixtureLayer Identification



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Section Date Age, years Rut Depth, in.0502 01-Jun-89 -1.2 0.7090502 11-Jun-90 -0.2 0.827502 29-Aug-90 0.0 0.000

0502 13-Apr-92 1.6 0.2360502 21-Mar-93 2.6 0.3150502 04-Jan-96 5.4 0.3940502 11-Jun-99 8.8 0.512

0503 01-Jun-89 -1.2 0.7090503 11-Jun-90 -0.2 0.787503 29-Aug-90 0.0 0.000

0503 13-Apr-92 1.6 0.1970503 21-Mar-93 2.6 0.3940503 04-Jan-96 5.4 0.4720503 11-Jun-99 8.8 0.591

0504 01-Jun-89 -1.2 0.7090504 11-Jun-90 -0.2 0.748504 29-Aug-90 0.0 0.000

0504 13-Apr-92 1.6 0.3150504 21-Mar-93 2.6 0.4720504 04-Jan-96 5.4 0.7090504 10-Jun-99 8.8 0.866

0505 01-Jun-89 -1.2 0.6690505 11-Jun-90 -0.2 0.669505 29-Aug-90 0.0 0.000

0505 13-Apr-92 1.6 0.2360505 21-Mar-93 2.6 0.3540505 04-Jan-96 5.4 0.3940505 10-Jun-99 8.8 0.433

0506 01-Jun-89 -1.2 0.7090506 11-Jun-90 -0.2 0.709506 29-Aug-90 0.0 0.000

0506 13-Apr-92 1.6 0.2360506 21-Mar-93 2.6 0.2760506 04-Jan-96 5.4 0.4330506 10-Jun-99 8.8 0.591

0507 01-Jun-89 -1.2 0.6690507 11-Jun-90 -0.2 0.709507 29-Aug-90 0.0 0.000

0507 13-Apr-92 1.6 0.3540507 21-Mar-93 2.6 0.5120507 04-Jan-96 5.4 0.6300507 10-Jun-99 8.8 0.827


0508 01-Jun-89 -1.2 0.6690508 11-Jun-90 -0.2 0.787508 29-Aug-90 0.0 0.000

0508 13-Apr-92 1.6 0.3150508 21-Mar-93 2.6 0.4720508 04-Jan-96 5.4 0.6300508 11-Jun-99 8.8 0.748

0509 01-Jun-89 -1.2 0.7870509 11-Jun-90 -0.2 0.787509 29-Aug-90 0.0 0.000

0509 13-Apr-92 1.6 0.1970509 21-Mar-93 2.6 0.3150509 04-Jan-96 5.4 0.3540509 10-Jun-99 8.8 0.551

0560 01-Jun-89 -1.2 0.5910560 11-Jun-90 -0.2 0.630560 29-Aug-90 0.0 0.000

0560 13-Apr-92 1.6 0.1970560 21-Mar-93 2.6 0.3150560 04-Jan-96 5.4 0.5120560 11-Jun-99 8.8 0.630



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J-6 Missouri SPS-5 Project

Construction Date: 8-27-1998 Elevation: 1250 Route: US 65 Latitude: 36.5

Functional Class: 2 Longitude: -93.23 AADTT (Both Directions): 800 to 1,480 Soil Type: Clayey Gravel

The Missouri SPS-5 project was originally identified as an alternate project for NCHRP 9-30A. It was included in the experimental matrix because of two basic reasons: (1) other SPS-5 projects had to be dropped because there was an insufficient amount of materials in the MRL while the Missouri project had sufficient material, and (2) lower levels of rutting were exhibited along this project in comparison to the other SPS-5 projects. The Missouri SPS-5 project is located in on State Route US-65 in the westbound traffic lane in Taney County, Missouri. US Route 65 is a four-lane divided highway. J-6.1 Construction History The existing flexible pavement was built in 1981. The HMA overlay was placed in 1998 and opened to traffic in August 1998. Figure MO-1

shows the rut depths measured over time for two of the Missouri SPS-5 test sections. As shown, the RAP section (0508) has consistently higher rut depths than the section without RAP (0507).

The construction report for this project was unavailable for review. No maintenance or rehabilitation activity was placed during the monitoring period for

measuring rut depths. J-6.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table MO-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B).

Table MO-1. Summary of Average Layer Thickness from LTPP Database

Test Section

Layer Thickness & Material Type HMA Overlay Existing Pavement



HMA Surface

HMA Binder

Crushed Stone Base

0502 RAP Mix 2.1 --- 1.4 7.0 4.6 0503 RAP Mix 1.0 2.9 1.1 7.4 4.0 0504 Virgin Mix 1.8 3.2 1.1 7.2 4.0 0505 Virgin Mix 2.2 --- 1.1 7.7 4.0 0506 Virgin Mix/Mill 2.1 2.0 0.0 6.1 6.0 0507 Virgin Mix/Mill 1.8 4.6 0.2 7.2 4.0 0508 RAP Mix/Mill 2.1 5.5 0.0 6.2 4.0 0509 RAP Mix/Mill 2.1 2.0 0.0 6.3 4.0



J - 82

Figure MO-1. Rut Depth Time-Series Data from LTPP Showing the Rutting Prior to and

after Overlay Placement J-6.3 Material Properties Reported During Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. The properties extracted from the LTPP database that were measured during construction and are being used to reconstitute the test specimens for the production test program are summarized below. [The Missouri DOT provided a copy of the mixture design sheets for each of the mixtures placed on this SPS-5 project.]

Asphalt Properties for HMA Overlay Mixtures: The asphalt properties for all mixtures used within this SPS-5 project are listed below.

Mix Type Asphalt Properties Layer

Surface Binder

RAP

Type of Asphalt PG 58-28 PG 58-28 Specific Gravity 1.0293 Penetration @ 77 4.5 3.7 Absolute Viscosity 4,200 5,400 Kinematic Viscosity 530 600 Total Asphalt Content 4.5 4.3

Virgin

Type of Asphalt PG 64-28 PG 64-22 Specific Gravity 1.042 1.046 Penetration @ 77 3.5 2.5 Absolute Viscosity 5,800 6,300 Kinematic Viscosity 880 640 Total Asphalt Content 4.9 4.5

00.050.1

0.150.2

0.250.3

0.350.4

-2.0 0.0 2.0 4.0 6.0 8.0

Age, years

Ave

rag

e R

ut

Dep

th,

in.

0507, Virgin Mix 0508, RAP Mix

SPS-5 HMA

overlay placed in 1998.



J - 83

Aggregate Properties for HMA Overlay Mixtures: The aggregate percentages used to establish the job mix formula for all mixtures used

within this SPS-5 project are listed below. All new aggregate was from the Journagan #7, Branson Pit/Quarry, Hollister.


RAP Virgin

Binder & Leveling Layer; Mix 1B

Recycled HMA 20 0 Stockpile # 98-2536 17 19 Stockpile # 98-2537 28 40 Stockpile # 98-2538 27 15 Stockpile #98-2535 7 25 Hydrated Lime 1 1 Effective Specific Gravity --- 2.6934

Wearing Surface; Mix 1C

Recycled HMA 20 0 Stockpile # 98-2537 40 58 Stockpile # 98-2538 29 14 Stockpile #98-2535 10 27 Hydrated Lime 1 1 Effective Specific Gravity --- 2.6980

All aggregates came from the Jorunagan #7 Branson Pit/Quarry, Hollister.

Aggregate Angularity: o Fine Aggregate Angularity – Not reported in the LTPP database or on the

mixture design sheets for any mixture; but, no natural sand and baghouse fines removed from the mixture. Thus, FAA > 45.


o Fine aggregate from LTPP records – Value from mixture design records – 2.710

o Coarse aggregate from LTPP records – Value from mixture design records – 2.692

Aggregate Absorption: o Fine aggregate from LTPP records –

Value from mixture design sheets – 1.0 o Coarse aggregate from LTPP records –

Value from mixture design sheets – 0.7 o Combined aggregate blend from mix design – 0.556

Mixture #1—RAP Mixture and Test Sections: The mixture design sheets were reviewed and compared to the test results included in the LTPP database. Most of the test results were similar between the LTPP test results and the values shown on the mixture design sheets. The values included in the LTPP database are being used to reconstitute the mixtures in the laboratory for production testing, which are listed below. Asphalt grade used in RAP mix – PG 58-28, Koch #2370 Asphalt Specific Gravity – 1.0293

o The asphalt specific gravity reported on the mix design sheets was 1.016. Hydrated Lime – 1.0 percent Amount of RAP used in binder and surface – 20 percent Bulk specific gravity of aggregate blend –



J - 84

o The bulk specific gravity of aggregate used in mixture design was not recorded on the mixture design sheets.

Amount of asphalt in RAP material – Not recorded Other mixture properties from LTPP and mix design records.

Mixture Property Obtained From: Layer or Mixture

Wearing Surface, 1C Binder Layer, 1B Total Asphalt Content

LTPP 4.5 4.3 Mix Design Sheets, JMF 4.2 3.7

Effective Specific Gravity, Aggregate

LTPP Mix Design Sheets Not recorded Not recorded

Maximum Specific Gravity

LTPP 2.495 2.509 Mix Design Sheets Not recorded Not recorded

Void in Mineral Aggregate

LTPP Mix Design Sheets 15.5 12.13

Air Voids Value to select target AC 4.6 3.8 LTPP 8.9 8.4

Aggregate Blend; The following percent passing values are averages from the LTPP

database in comparison to the values taken from the job mix formula. Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF; 1B 100 100 94 84 74 52 26.4 16.9 12.3 5.4 JMF; 1C 100 100 100 99 88 60 29.4 18.7 13.3 5.7 LTPP; 1B 100 100 96 54 26.5 12.5 8.5 6.6 LTPP; 1C 100 100 100 100 100 60.5 31.0 13.5 9.5 7.5

Mixture #2—Virgin Mixture and Test Sections: Asphalt grade used in virgin mix – PG-62-22 for the binder layer or mix

and PG 64-28 for the wearing surface; Koch #23270.

Asphalt Specific Gravity – 1.044 o The asphalt specific gravity reported on the mix design sheets was 1.032.

Hydrated lime – 1.0 percent Bulk specific gravity of aggregate blend –


Other mixture properties from LTPP and mix design records.

Mixture Property Obtained From: Layer or Mixture Wearing Surface, 1C Binder Layer, 1B

Total Asphalt Content

LTPP 4.9 4.5 Mix Design Sheets, JMF 5.0 4.5

Effective Specific Gravity, Aggregate

LTPP Mix Design Sheets Not Recorded Not Recorded

Maximum Specific Gravity

LTPP 2.490 2.502 Mix Design Sheets Not Recorded Not Recorded

Void in Mineral Aggregate

LTPP Mix Design Sheets 16.20 14.74

Air Voids Value to select target AC 4.58 4.3 LTPP 8.4 8.2



J - 85

Aggregate Blend; The following percent passing values are averages from the LTPP database in comparison to the values taken from the job mix formula.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF; 1B 100 100 93 82 71 50 28 17.4 11.8 4.4 JMF; 1C 100 100 100 99 84 56 29 18.3 12.4 4.7 LTPP; 1B 100 100 97 56 29 11.5 8 6.0 LTPP; 1C 100 100 100 100 100 60 33 12 8 5.6

Existing HMA Layer/Mixture: Asphalt Specific Gravity – Not reported Asphalt Content by Weight – 4.1 for the binder layer and 4.2 for the wearing surface. Maximum Specific Gravity – 2.5352 for the binder layer and 2.5197 for the wearing

surface. Air Voids – 10.2 percent for the binder layer and 5.6 percent for the

existing wearing surface. Aggregate Blend for the Two Layers/Mixtures, percent passing:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF Not available from construction records. LTPP; 1B 100 100 100 51 32.3 17.3 12.7 9.6 LTPP; 1C 100 100 100 53 33 18 11.7 8.5

J-6.4 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section report. The maximum rut depths measured along the individual test sections varied from 0.157 inches (RAP mixture) to 0.354 inches (RAP mixture)—a difference between the test sections of the same HMA overlay mixture. Figure MO-2 shows the measured rut depths as a function of time for all test sections within the SPS-5 project. Mixture type (RAP versus virgin mixes) did not have a significant effect or impact of the magnitude of the rut depths, but the sections with the RAP mixture consistently have higher rut depths. The RAP mixture does have slightly softer asphalt, which could explain the higher rut depths. The following lists the average maximum rut depths measured on the sections with the different HMA mixtures (RAP and virgin).




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Figure MO-2. Rut Depths Measured Over Time for the SPS-5 Test Sections

Figure MO-3 shows the effect of HMA overlay thickness and mixture type on the maximum rut depth measured along each of the SPS-5 test sections. As shown, HMA overlay thickness has no systematic impact on the rut depths for the Missouri SPS-5 test sections without RAP. Conversely, the rut depth increases with increasing overlay thickness for the SPS-5 test sections without RAP. It is expected the majority of the rutting occurred within the wearing surface of both mixtures. Although it would be difficult to confirm through trenches, it is expected that more rutting occurred within the binder layer of the sections with the RAP mixture. In summary, the RAP and virgin mixtures were used in the NCHRP 9-30A production testing program.

Figure MO-3. Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth J-6.5 Forensic Investigation of Missouri SPS-5 Project Although the rut depths do not appear to be strongly related to HMA mixture type and thickness, the Missouri SPS-5 project was identified as a candidate for a forensic investigation. Test sections 0505 (a virgin section) and 0508 (a RAP section) were the sections selected for trenching, because these sections represent a large difference in measured rut depths over the monitoring period for the different HMA overlay mixtures (refer to figure MO-2).

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-2.0 0.0 2.0 4.0 6.0 8.0

Age, years

Ave

rag

e M

ax.

Ru

t D

epth

, in

.

0502, RAP

0503, RAP

0508, RAP

0509, RAP

0504, Virgin

0505, Virgin

0506, Virgin

0507, Virgin

00.050.1

0.150.2

0.250.3

0.350.4

0 2 4 6 8


Ave

rag

e M

ax.

Ru

t D

epth

, in

.

RAP Mixtures Virgin Mixtures



J - 87

Six 6-inch diameter cores were planned from all test sections trenched for evaluating the effect of aging and determining the difference between the permanent deformation parameters for the in place mixtures. A field investigation, however, was not conducted because of scheduling conflicts with the DOT in providing for traffic control and the benefit of cutting the trenches was believed to be minimal. J-6.6 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. Figures MO-4 and MO-5 present the dynamic modulus values measured on the HMA overlay mixture with and without RAP, respectively, which were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The mixtures with RAP exhibited lower dynamic moduli at the higher test temperatures; probably as a result of the slightly softer asphalt that was used in the RAP mixtures. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E.

Figure MO-4. Dynamic Modulus Values Measured on the HMA Mixture without RAP



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Figure MO-5. Dynamic Modulus Values Measured on the HMA Mixture with RAP

J-6.7 Rut Depth Predictions Using the Global Transfer Function Coefficients Figures MO-6 and MO-7 compare the predicted and measured rut depths for all transfer functions using the global rut depth coefficients for selected test sections with RAP (0502 and 0508) and without RAP (0505 and 0507), respectively. Test sections 0502 and 0505 have similar pavement structures and have the thinner overlays, while sections 0507 and 0508 have the thicker HMA overlays. The comparison of the predicted and measured rut depths over time for the different rut depth transfer functions using the global plastic deformation coefficients was similar. In general the Asphalt Institute and WesTrack transfer functions over predict the measured rut depths for these four test sections, while the Verstraeten and MEPDG transfer function generally under predict the measured rut depths. The Verstraeten and WesTrack transfer functions, however, provided a closer simulation of the rut depth growth rate even though the predicted magnitudes of the rut depths exhibited a significant bias. Conversely, the Asphalt Institute and MEPDG predicted significantly greater increases in rut depth over time. This observation was true for the other test sections not shown in Figures MO-6 and MO-7. J-6.8 Field-Derived Coefficients of the Transfer Functions This section summarizes the comparison of the predicted and measured rut depths using laboratory permanent deformation test results in support of the different rut depth transfer functions. Table MO-2 summarizes the field-derived coefficients of each transfer function and test section, while Figures MO-8 and MO-9 compare the predicted and measured rut depth for the test sections with and without RAP, respectively. The test sections with and without milling exhibited a similar comparison between the measured and predicted rut depths. As shown, each transfer function accurately predicted the measured rut depths and increase in growth rate over time. In other words, the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.



J - 89

Figure MO-6. Comparison of the Predicted and Measured Rut Depths Using the Global Coefficients for each Transfer Function for SPS-5 Sections 0502 and 0508; Mixtures with

RAP



J - 90

Figure MO-7. Comparison of the Predicted and Measured Rut Depths Using the Global

Coefficients for each Rut Depth Transfer Function for SPS-5 Sections 0505 and 0507; Mixtures without RAP



J - 91

Figure MO-8. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0504 and 0505 (Mixtures

without RAP)



J - 92

Figure MO-9. Examples of Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0503

(Mixtures with RAP)

Table MO-2. Field-Derived Slope and Intercept


1-40B Modified


Slope All 0.23 0.44 0.23 0.23 0.23

Intercept

0502-RAP -1.90 -2.43 -0.51 285 1.0 0503-RAP -1.78 -2.43 290 2.0 0508-RAP -1.71 -2.43 -0.85 270 1.48 0509-RAP -2.26 -2.43 260 0.83 0504-Virgin -1.58 -2.46 -0.85 283 1.55 0505-Virgin -1.65 -2.46 -0.51 280 1.5 0506-Virgin -1.66 -2.46 285 1.35 0507-Virgin -1.65 -2.46 270 1.4



J - 93



Surface Binder Surface Binder

Bulk Specific Gravity Gmb 2.273 2.298 2.281 2.297 2.276

Maximum Specific Gravity Gmm 2.495 2.509 2.49 2.502 2.5352

Air Voids, % Va 8.90 8.41 8.39 8.19 10.22 #DIV/0!

Air Voids for Target Asphalt Content, % Va(design) 4.00 4.00 4.00 4.00 4.00

Total Asphalt Content by Weight, % Pb 4.50 4.30 4.90 4.50 4.20

Optimum/Saturation Asphalt Content, % Pb(0pt) 4.20 4.00 5.00 4.50 4.50

Aggregate Effective Specific Gravity Gse 2.674 2.682 2.682 2.678 2.707 #DIV/0!

Bulk Specific Gravity of Aggregate Blend Gsb 2.623 2.631 2.631 2.627 2.638 #DIV/0!

Effective Asphalt Content by Volume, % Vbe 8.356 7.998 9.165 8.309 7.129 #DIV/0!

Voids in Mineral Aggregate, % VMA 17.3 16.4 17.6 16.5 17.4 #DIV/0!Voids Filled with Asphalt, % VFA 48.4 48.7 52.2 50.4 41.1 #DIV/0!

Gradation Factor (GI Term) Kr3 0.40 0.40 0.40 0.40 0.40

Fine Aggregate Factor Findex 0.95 0.95 0.95 0.95 0.95

Coarse Aggregate Factor Cindex 0.95 0.95 0.95 0.95 0.95

Log Kr1 2.50 2.45 2.35 2.41 3.00

Rut Depth Coefficient kr1 -2.348 -2.430 -2.471 -2.459 -1.886 #DIV/0!

Temperature Exponent kr2 1.871 1.861 1.712 1.737 1.688 #DIV/0!

Traffic Loadings Exponent kr3 0.463 0.465 0.424 0.432 0.403 #DIV/0!

Asphalt Specific Gravity; Combined Gb 1.0293 1.0293 1.042 1.046 1.035

Kr1 Value 316.2278 281.8383 223.8721 257.0396 1000 1Absorbed Asphalt by Weight, % 0.75 0.75 0.75 0.75 1kr1 Log Value 12.61455 10.4466 9.507096 9.766948 36.55941 #DIV/0!

Missouri SPS-5

Layer IdentificationRAP Virgin Existing



J - 94

J-6.10 Average Rut Depth Measurements Extracted from LTPP Database for the Missouri SPS-5 Project

Section Date Age, years Rut Depth, in.0502 23-Jul-98 -0.1 0.315502 29-Aug-98 0.0 0.000

0502 17-Dec-98 0.3 0.1180502 09-Aug-99 0.9 0.2760502 02-Feb-00 1.4 0.1970502 13-Jun-01 2.8 0.2360502 15-Sep-01 3.0 0.2360502 31-Oct-02 4.2 0.1970502 17-Jul-03 4.9 0.1970502 22-Oct-03 5.2 0.1970502 19-Nov-04 6.2 0.236

0503 23-Jul-98 -0.1 0.315503 29-Aug-98 0.0 0.000

0503 20-Jan-99 0.4 0.1180503 09-Aug-99 0.9 0.2360503 01-Feb-00 1.4 0.2360503 13-Jun-01 2.8 0.2760503 15-Sep-01 3.0 0.2760503 31-Oct-02 4.2 0.2360503 17-Jul-03 4.9 0.2360503 22-Oct-03 5.2 0.3150503 19-Nov-04 6.2 0.315

0504 10-Jun-98 -0.2 0.197504 29-Aug-98 0.0 0.000

0504 16-Dec-98 0.3 0.1180504 09-Aug-99 0.9 0.2360504 31-Jan-00 1.4 0.1570504 12-Jun-01 2.8 0.1570504 15-Sep-01 3.0 0.1970504 31-Oct-02 4.2 0.1570504 17-Jul-03 4.9 0.1970504 14-Oct-03 5.1 0.2360504 15-Nov-04 6.2 0.236

0505 10-Jun-98 -0.2 0.236505 29-Aug-98 0.0 0.000

0505 16-Dec-98 0.3 0.1180505 09-Aug-99 0.9 0.1970505 31-Jan-00 1.4 0.1570505 12-Jun-01 2.8 0.1570505 15-Sep-01 3.0 0.1970505 29-Oct-02 4.2 0.1570505 17-Jul-03 4.9 0.1180505 14-Oct-03 5.1 0.1970505 15-Nov-04 6.2 0.197

LTPP Data Eelement: MAX_MEAN_DEPTH_WIRE_REF

0506 10-Jun-98 -0.2 0.157506 29-Aug-98 0.0 0.000

0506 16-Dec-98 0.3 0.1180506 09-Aug-99 0.9 0.1970506 31-Jan-00 1.4 0.1570506 12-Jun-01 2.8 0.1180506 15-Sep-01 3.0 0.1570506 31-Oct-02 4.2 0.1570506 18-Mar-03 4.6 0.1570506 17-Jul-03 4.9 0.1180506 15-Oct-03 5.1 0.1570506 15-Nov-04 6.2 0.1570506 27-Mar-06 7.6 0.157

0507 22-Jul-98 -0.1 0.315507 29-Aug-98 0.0 0.000

0507 19-Jan-99 0.4 0.0790507 09-Aug-99 0.9 0.1570507 01-Feb-00 1.4 0.1180507 12-Jun-01 2.8 0.0790507 15-Sep-01 3.0 0.1970507 31-Oct-02 4.2 0.0790507 17-Jul-03 4.9 0.1180507 15-Oct-03 5.1 0.1180507 15-Nov-04 6.2 0.1180507 27-Mar-06 7.6 0.157

0508 22-Jul-98 -0.1 0.276508 29-Aug-98 0.0 0.000

0508 15-Dec-98 0.3 0.1570508 09-Aug-99 0.9 0.2360508 01-Feb-00 1.4 0.2760508 13-Jun-01 2.8 0.2760508 15-Sep-01 3.0 0.2360508 31-Oct-02 4.2 0.1970508 18-Mar-03 4.6 0.1970508 17-Jul-03 4.9 0.2760508 16-Oct-03 5.1 0.3150508 19-Nov-04 6.2 0.3150508 27-Mar-06 7.6 0.354

0509 22-Jul-98 -0.1 0.236509 29-Aug-98 0.0 0.000

0509 16-Jan-99 0.4 0.0790509 09-Aug-99 0.9 0.2360509 01-Feb-00 1.4 0.1570509 13-Jun-01 2.8 0.1570509 15-Sep-01 3.0 0.1570509 31-Oct-02 4.2 0.1180509 17-Jul-03 4.9 0.1570509 16-Oct-03 5.1 0.1570509 15-Nov-04 6.2 0.1570509 27-Mar-06 7.6 0.157



J - 95

J-6.11 MEPDG Input Summary: Missouri SPS-5 Test Section Example The following is a summary of the inputs that were used for the MEDPG runs using the NCHRP 9-30A version of the MEDPG. These are provided as an example to document the data and information included for this SPS-5 project.

Limit Reliability

61.6 172 90 2000 90 25 90 1000 90 25 90 0.25 90 0.75 90

630 1 100 100 60

Project: 29_0503_2 Westrack.dgp

General Information Description:

Design Life 10 yearsExisting pavement construction: July, 1998Pavement overlay construction: August, 1998Traffic open: September, 1998Type of design Flexible

Analysis Parameters

Performance CriteriaInitial IRI (in/mi)Terminal IRI (in/mi)AC Surface Down Cracking (Long. Cracking) (ft/mile):AC Bottom Up Cracking (Alligator Cracking) (%):AC Thermal Fracture (Transverse Cracking) (ft/mi):Chemically Stabilized Layer (Fatigue Fracture)Permanent Deformation (AC Only) (in):Permanent Deformation (Total Pavement) (in):

Location: USH-65 Northbound, Taney CountyProject ID: Section ID: Date: 1/22/2008 Station/milepost format: Miles: 0.000Station/milepost begin: 69.6Station/milepost end: Traffic direction: North bound





J - 96


0.75 0.92 0.72 0.66 0.53 0.98 0.69 0.92 0.91 1.00 0.77 0.95 0.62 0.66 0.59 0.99 0.85 0.95 1.03 1.00 0.93 1.08 0.95 0.76 0.91 1.03 1.06 1.03 1.13 1.00 1.10 1.03 1.16 1.09 1.21 1.04 1.10 1.03 1.03 1.00 1.32 1.00 1.03 1.29 1.24 1.01 0.98 1.06 0.93 1.00 0.99 0.99 1.21 1.22 1.38 1.04 1.38 1.08 1.33 1.00 0.84 0.99 1.03 1.02 1.32 0.97 1.26 1.02 1.03 1.00 0.67 0.95 1.21 1.32 1.18 1.02 1.25 1.09 1.03 1.00 0.86 0.96 1.30 1.12 1.20 1.03 1.00 1.01 0.93 1.00 1.23 1.03 1.13 1.09 1.11 1.04 0.95 1.05 0.93 1.00 1.47 1.00 0.88 1.02 0.80 0.94 0.81 0.90 0.93 1.00 1.08 1.11 0.75 0.76 0.53 0.91 0.68 0.86 0.83 1.00

Midnight 2.3% Noon 5.9%

3.0% 1:00 am 2.3% 1:00 pm 5.9% 19.8% 2:00 am 2.3% 2:00 pm 5.9% 7.0% 3:00 am 2.3% 3:00 pm 5.9% 0.9% 4:00 am 2.3% 4:00 pm 4.6% 17.1% 5:00 am 2.3% 5:00 pm 4.6% 49.0% 6:00 am 5.0% 6:00 pm 4.6% 0.6% 7:00 am 5.0% 7:00 pm 4.6% 2.3% 8:00 am 5.0% 8:00 pm 3.1% 0.2% 9:00 am 5.0% 9:00 pm 3.1% 0.1% 10:00 am 5.9% 10:00 pm 3.1% 11:00 am 5.9% 11:00 pm 3.1%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

18 10 12

1.62 0.39 0.00 0.00 2.00 0.00 0.00 0.00 1.02 0.99 0.00 0.00 1.00 0.26 0.83 0.00 2.38 0.67 0.00 0.00 1.13 1.93 0.00 0.00 1.19 1.09 0.89 0.00 4.29 0.26 0.06 0.00 3.52 1.14 0.06 0.00 2.15 2.13 0.35 0.00

8.5 12 120 51.6 49.2 49.2

Traffic -- Volume Adjustment FactorsMonthly Adjustment Factors (Level 1, Site Specific - MAF)

Vehicle ClassMonth





Vehicle Class

Growth Rate

GrowthFunction

Class 4 LinearClass 5 LinearClass 6 LinearClass 7 LinearClass 8 LinearClass 9 LinearClass 10 LinearClass 11 LinearClass 12 LinearClass 13 Linear




Vehicle Class

Single Axle

Tandem Axle

Tridem Axle

Quad Axle

Class 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12Class 13






J - 97

36.5 -93.2333 1250 3

-10 -16 -22 -28 -34 -40 -46

LoadTime(sec)

LowTemp.

-4ºF(1/psi)

Mid.Temp.14ºF

(1/psi)

HighTemp.32ºF


Climate icm file:

D:\users\Alex\MO_Westrack_Jul 21 08\29_0500.icm Latitude (degrees.minutes)Longitude (degrees.minutes)Elevation (ft)Depth of water table (ft)


HMA E* Predictive Model: NCHRP 1-37A viscosity based model.HMA Rutting Model coefficients: NCHRP 1-37A coefficientsEndurance Limit (microstrain): None (0 microstrain)Reflective cracking analysis: No




Volumetric Properties as BuiltEffective binder content (%): 7.5Air voids (%): 7Total unit weight (pcf): 145



Asphalt MixCumulative % Retained 3/4 inch sieve: 2.6Cumulative % Retained 3/8 inch sieve: 18.1Cumulative % Retained #4 sieve: 43.5% Passing #200 sieve: 5.6


High temp.°C


46525864707682


-10 -16 -22 -28 -34 -40 -46

Layer 2 -- Asphalt concreteMaterial type: Asphalt concreteLayer thickness (in): 2.9


Volumetric Properties as BuiltEffective binder content (%): 6.89Air voids (%): 7Total unit weight (pcf): 145



Asphalt MixCumulative % Retained 3/4 inch sieve: 2.6Cumulative % Retained 3/8 inch sieve: 18.1Cumulative % Retained #4 sieve: 43.5% Passing #200 sieve: 5.6


High temp.°C


46525864707682



J - 98

Layer 3 -- Asphalt concrete (existing)Material type: Asphalt concrete (existing)Layer thickness (in): 1.1
















J - 99

Value 4.0507 1.0091 0.72961 126.8

Layer 5 -- A-1-aUnbound Material: A-1-aThickness(in): 4


ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 1Liquid Limit (LL) 6Compacted Layer NoPassing #200 sieve (%): 13.4Passing #40 20Passing #4 sieve (%): 51D10(mm) 0.01398D20(mm) 0.425D30(mm) 1.285D60(mm) 6.096D90(mm) 12.98


#200 13.4#100 #80 #60 #50 #40 20#30 #20 #16 #10 34#8 #4 51

3/8" 761/2" 893/4" 1001" 100

1 1/2" 1002" 100

2 1/2" 3" 100

3 1/2" 4"



Parametersabc

Hr.

Value 103.69 0.71193 0.24709 500

Layer 6 -- A-2-7Unbound Material: A-2-7Thickness(in): Semi-infinite


ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 29Liquid Limit (LL) 50Compacted Layer NoPassing #200 sieve (%): 30.2Passing #40 35Passing #4 sieve (%): 53D10(mm) 0.0008954D20(mm) 0.008017D30(mm) 0.07178D60(mm) 6.718D90(mm) 31.89


#200 30.2#100 #80 #60 #50 #40 35#30 #20 #16 #10 44#8 #4 53

3/8" 671/2" 743/4" 811" 87

1 1/2" 922" 96

2 1/2" 3" 100

3 1/2" 4"

Calculated/Derived ParametersMaximum dry unit weight (pcf): 119.6 (derived)Specific gravity of solids, Gs: 2.70 (derived)Saturated hydraulic conductivity (ft/hr): 6.954e-006 (derived)Optimum gravimetric water content (%): 11.2 (derived)Calculated degree of saturation (%): 73.9 (calculated)


Parametersabc

Hr.



J - 100

0.007566 3.9492 1.281

1 1

-3.35412 1.5606 0.4791

1.5

1 1

0.406 0.27

7 3.5 0 1000



k1k2k3



k1k2k3


0.24*POWER(RUT,0.8026)+0.001


k1



k1k2


Granular:k1

Fine-grain:k1





J - 101

J-7 Montana SPS-5 Project


Functional Class: 1 Longitude: -110.01 AADTT (Both Directions): 1,300 to 1,950 Soil Type: Clayey Gravel with Sand

The Montana SPS-5 project is located in on Interstate Highway 90 in the westbound traffic lane, just west of Big Timber, Montana in Sweet Grass County. Interstate 90 is a four-lane divided highway. J-7.1 Construction History The existing flexible pavement was built in 1987. The HMA overlay was placed in 1991 and opened to traffic in September 1991. No construction issues or problems were reported for the HMA overlay test sections. A chip seal with a modified binder was placed on the pavement surface of all test sections

during the monitoring period for measuring rut depths. The chip seal was placed in 2001. The SPS-5 project was taken out of service or de-assigned from the LTPP SPS-5 experiment

in May 2001. However, the sections in this project were monitored past that date. Figure MT-1 shows the rut depths prior to overlay placement, after overlay placement, and after the de-assigned date of 2001. The rut depths decreased in 2001 as a result of a rehabilitation strategy within that year and continued to decrease for some sections after 2001.

J-7.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table MT-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B).

Table MT-1. Summary of Average Layer Thickness from LTPP Database

Test Section

Layer Thickness & Material Type HMA Overlay Existing Pavement



HMA Surface

Crushed Stone Base

Crushed Stone Subbase

0502 RAP Mix 2.6 --- 4.3 2.8 14.4 0503 RAP Mix 4.6 --- 4.2 4.2 14.5 0504 Virgin Mix 5.6 --- 4.4 3.5 15.6 0505 Virgin Mix 2.4 --- 4.8 2.8 15.3 0506 Virgin Mix/Mill 2.1 2.1 2.6 2.8 15.3 0507 Virgin Mix/Mill 4.9 2.3 2.3 3.5 15.6 0508 RAP Mix/Mill 5.0 2.1 2.2 4.4 14.8 0509 RAP Mix/Mill 2.4 2.1 2.7 3.8 15.0

0560 Virgin Mix

w/Kraton/Mill 4.6 --- 4.4 3.6 14.4

0561 Virgin Mix

w/Polybuilt/Mill 4.6 --- 4.5 3.6 14.4

NOTE: Section 0507 has a rigid layer within 234 inches of the pavement surface.



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Figure MT-1. Rut Depth Time-Series Data from LTPP Showing the Rutting Prior to

Overlay and After the Second Rehabilitation Strategy J-7.3 Material Properties Reported During Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Those properties extracted from the LTPP database that were measured during construction and are being used to reconstitute the test specimens for the production test program are summarized below. [The Montana DOT provided a copy of the mixture design sheets for each of the mixtures placed on this SPS-5 project.]

Aggregate Properties for HMA Overlay Mixtures: The new aggregate included in the mixture design for both the RAP and virgin mixtures

for the binder layer was provided by Empire Sand and Gravel. Aggregate Angularity:

o Fine Aggregate Angularity – Not reported in the LTPP database or on the mixture design sheets for any mixture; but, no natural sand and baghouse fines removed from the mixture. Thus, FAA > 45.


o Fine aggregate from LTPP records – 2.68 Value from mixture design records – 2.708

o Coarse aggregate from LTPP records – 2.72 Value from mixture design records – 2.709

Aggregate Absorption: o Fine aggregate from LTPP records – 0.74

Value from mixture design sheets – 0.393 o Coarse aggregate from LTPP records – 0.63

Value from mixture design sheets – 0.922 o Combined aggregate blend from mix design – 0.556

0

0.1

0.2

0.3

0.4

0.5

0.6

-5.00 0.00 5.00 10.00 15.00

Age After Initial Overlay, years

Ave

rag

e R

ut

Dep

th,

in.

RAP, 0503 Virgin, 0504

Second Maint./Rehab. strategy placed in

2001.

SPS-5 HMA overlay placed

in 1991.



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Mixture #1—RAP Mixture and Test Sections: The mixture design sheets were reviewed and compared to the test results included in the LTPP database. Most of the test results were similar between the LTPP test results and the values shown on the mixture design sheets. The values included in the LTPP database are being used to reconstitute the mixtures in the laboratory for production testing, which are listed below. Asphalt grade used in RAP mix – 85/100 Exxon Asphalt Specific Gravity – 1.039

o The asphalt specific gravity was not included on the mixture design sheets. Hydrated Lime – 1.4 percent Amount of RAP used in binder and surface – 30 percent Bulk specific gravity of aggregate blend – 2.669


Effective specific gravity of aggregate – 2.710 Amount of asphalt in RAP material – Not recorded Total asphalt content by weight – 4.8

o The target asphalt content to be added was 3.7 percent which resulted in a total asphalt content (including the RAP material) of 6.0 percent.

Maximum Specific Gravity of RAP mix – 2.5173 o The maximum specific gravity at the target asphalt content reported on the

mixture design sheet was 2.532. Voids in Mineral Aggregate – 14.4

o The VMA at the target asphalt content from the mixture design sheet was 13.0 percent.

Average Air Voids at construction; the upper layer properties was used to reconstitute the test specimens for laboratory testing because only a portion of the test sections included the lower layer (the lower layer has the same properties as the upper layer, with the exception of the air voids):

o Target asphalt content selected at – 3.6 percent. o Lower layer of overlay – 6.2 percent o Upper layer of overlay (surface) – 4.7 percent

Aggregate Blend for the 19 mm PMS, Grade B Special RAP Mixture; the following percent passing values are averages from the LTPP database in comparison to the values taken from the Job Mix Formula (JMF). As tabulated, the gradations are similar with the exception that the LTPP data found more fines in the mixture.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF 100 100 100 83 69 49 32 16 --- 5.7 LTPP Data 100 100 100 89 74 51 34 18.7 12.0 7.8

Mixture #2—Virgin Mixture and Test Sections: Asphalt grade used in virgin mix – 85/100 Exxon Asphalt Specific Gravity – 1.04

o The asphalt specific gravity was not included on the mixture design sheets. Hydrated lime – 1.4 percent Bulk specific gravity of aggregate blend – 2.677


Effective specific gravity of aggregate – 2.719 Total asphalt content by weight – 5.1



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o The target asphalt content was 5.0 percent at 2.6 percent air voids. Maximum Specific Gravity – 2.5113

o The maximum specific gravity reported on the mix design sheets at the target asphalt content was 2.530.

Voids in Mineral Aggregate of virgin mix – 14.0 o The VMA at the target asphalt content from the mixture design sheet was 13.6

percent. Average Air Voids at construction; the upper layer properties was used to reconstitute the

test specimens for laboratory testing because only a portion of the test sections included the lower layer (the lower layer has the same properties as the upper layer, with the exception of the air voids):

o Target asphalt content selected at – 2.6 percent. o Lower layer of overlay – 3.9 percent o Upper layer of overlay (surface) – 3.4 percent

Aggregate Blend for the 19 mm PMS, Grade B Mixture; the following percent passing values are averages from the LTPP database in comparison to the values taken from the Job Mix Formula (JMF). As tabulated, the gradations reported by LTPP indicate a slightly finer mix than from the JMF. However, the JMF included on the mix design sheets did not include the RAP material.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF 100 100 100 83 69 49 32 16 --- 5.7 LTPP Data 100 100 100 88 76 55 37 19.7 13.0 8.3

Existing HMA Layer/Mixture: Asphalt Specific Gravity – 1.046 Asphalt Content by Weight – 5.5 Maximum Specific Gravity – 2.4747 Air Voids – 5.6 Aggregate Blend for the Two Layers/Mixtures, percent passing:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 JMF Not available from construction records. LTPP Data 100 100 100 94 86 63 41 22.3 13.3 8.7

J-7.4 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section report. The maximum rut depths measured along the individual test sections varied from 0.236 inches (RAP mixture) to 0.512 inches (virgin mixture)—a significant difference between the test sections. The two supplemental test sections with the polymer modified mixtures even had much lower rut depths than any of the core test sections. Figure MT-2 shows the measured rut depths as a function of time for all test sections within the SPS-5 project, with the exception of the supplemental test sections. As shown, mixture type (RAP versus virgin mixes) was found to have no systematic effect or impact of the magnitude of the rut depths.



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Figure MT-2. Rut Depths Measured Over Time for Each of the Core SPS-5 Test Sections;

from Prior to Overlay Placement to the Second Rehabilitation Activity Figure MT-3 shows the rut depths measured over time for the supplemental test sections with the polymer modified asphalt (PMA) mixtures in comparison the one of the RAP and virgin sections. As shown, the supplemental sections with the PMA mixtures have exhibited much less rutting than the core sections with neat asphalt. The following lists the average maximum rut depths measured on the sections with the different HMA mixtures (RAP, virgin, and PMA mixtures) and between the test sections with and without milling.

Type of Overlay Mixture Statistical Parameter RAP Mixtures Virgin Mixtures PMA Mixtures Mean Max. Rut Depth, in. 0.384 0.394 0.156 Standard Deviation, in. 0.130 0.0963 0.0014 Coefficient of Variation, % 33.9 24.5 0.9 Surface Preparation for Core Test Sections Statistical Parameter Milled Surface No Milling Mean Max. Rut Depth, in. 0.414 0.364 Standard Deviation, in. 0.131 0.087 Coefficient of Variation, % 31.6 23.9

As shown, the test sections that include milling have slightly greater rutting in comparison to the test sections without milling. The cores that were originally recovered from these test sections suggest that surface preparation did not have a significant impact on the bond between the existing surface and HMA overlay. The reason for the higher rut depths for the sections where the existing surface was milled is unknown.



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Figure MT-3. Rut Depths Measured Along the Supplemental Test Sections in Comparison

to Selected Core Sections of the SPS-5 Project Figure MT-4 shows the effect of HMA overlay thickness and mixture type on the maximum rut depth measured along each of the SPS-5 test sections. As shown, HMA overlay thickness has no systematic impact on the rut depths for this SPS-5 project.

Figure MT-4. Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth In summary, the RAP and virgin mixtures were used in the NCHRP 9-30A production testing program. The PMA mixture for the supplemental sections was also selected to be included in the production test program, but an insufficient amount of the modified asphalt was available in the MRL. More importantly, there is an insufficient amount of aggregate in the MRL to support the production testing for all three mixtures. The aggregate supplier was contacted and additional aggregate are being obtained to include that mixture within the test program, assuming that an adequate amount of the modified asphalt can be obtained from the asphalt-modified supplier. The test sections included in the comparison of the predicted and measured rut depths were grouped by those with and without a milled surface because this feature had the greatest impact on the measured rutting.

0

0.1

0.2

0.3

0.4

0.5

0.6

0 2 4 6 8


Ave

rag

e M

ax.

Ru

t D

epth

, in

.

RAP Sections Virgin Sections PMA Sections

0

0.1

0.2

0.3

0.4

0.5

0.6

-5.00 0.00 5.00 10.00 15.00

Age, years

Ave

rag

e R

ut

Dep

th,

in.

Suppliemental0560

Supplemental0561

RAP 0509

Virgin 0506



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J-7.5 Forensic Investigation of Montana SPS-5 Project Although the rut depths do not appear to be related to HMA mixture type and thickness for the core test sections, the Montana SPS-5 project was identified as a potential candidate for a forensic investigation. Test sections 0505 (a virgin section) and 0508 (a RAP section are the sections selected for trenching because these sections represent a large difference in measured rut depths over the monitoring period for the different HMA overlay mixtures (refer to figure MT-2). If a sufficient amount of the modified asphalt can be obtained from the asphalt supplier, section 30-0560 will be trenched and cores recovered for the production testing program. The forensic investigation of this project was planned but was not completed, because of scheduling conflicts and the minimal benefit from the trenches. Thus, the field investigation and trenching was dropped. Six 6-inch diameter cores were recovered from specific test sections for evaluating the effect of aging and determining the difference between the permanent deformation parameters for the in place mixtures. J-7.6 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. Figure MT-4 presents the dynamic modulus values measured on the HMA overlay without RAP (defined as virgin mixtures), which were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E.

Figure MT-5. Dynamic Modulus Values Measured on the HMA Mixture without RAP

J-7.7 Rut Depth Predictions Using the Global Transfer Function Coefficients Figures MT-6 and MT-7 compare the predicted and measured rut depths for all transfer functions using the global rut depth coefficients for the test sections with RAP and without RAP in the mixtures, respectively. For Figure MT-6, Section 0508 has a milled surface, while no milling was used on section 0502. For Figure MT-7), section 0505 excludes milling, while section 0507 has a



J - 108

milled surface. Both of these two SPS-5 test sections have similar pavement structures. The comparison of the predicted and measured rut depths over time for the different rut depth transfer functions using the global plastic deformation coefficients was similar. In general the NCHRP 1-40B, Verstraeten, and WesTrack transfer functions predicted similar growth rates or increases in rut depth over time, although the magnitudes of the predicted rut depths were different. Conversely, the Asphalt Institute and MEPDG predicted significantly greater increases in rut depth over time. This observation was true for the other test sections not shown in Figures MT-6 and MT-7.

Figure MT-6. Comparison of the Predicted and Measured Rut Depths Using the Global Coefficients for each Transfer Function for SPS-5 Sections 0502 (No Milling) and 0508

(Milled Surface); Mixtures with RAP



J - 109

Figure MT-7. Comparison of the Predicted and Measured Rut Depths Using the Global Coefficients for each Rut Depth Transfer Function for SPS-5 Sections 0505 (No Milling)

and 0507 (Milled Surface); Mixtures without RAP J-7.8 Field-Derived Coefficients of the Transfer Functions This section summarizes the comparison of the predicted and measured rut depths using laboratory permanent deformation test results in support of the different rut depth transfer functions. Table MT-2 summarizes the field-derived coefficients of each transfer function and test section, while Figures MT-8 and MT-9 compare the predicted and measured rut depth for the test sections with and without RAP, respectively. The test sections with and without milling exhibited a similar comparison between the measured and predicted rut depths. As shown, each transfer function accurately predicted the measured rut depths. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.



J - 110

Figure MT-8. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and

the Field-Derived Plastic Deformation Coefficients for Sections 0505 (No Milling) and 0507 (Milled Surface); Mixtures without RAP



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Figure MT-9. Examples of Predicted versus Measured Rut Depths using MEPDG Version

9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 (No Milling) and 0508 (Milled Surface); Mixtures with RAP



J - 112

Table MT-2. Field-Derived Slope and Intercept


1-40B Modified


Slope All 0.35 0.19 0.35 0.35 0.35

Intercept

0502-RAP -2.15 -2.48 0503-RAP -2.20 -2.48 0508-RAP -2.50 -2.48 0509-RAP -2.25 -2.48 0504-Virgin -2.28 -2.13 0505-Virgin -2.57 -2.13 0506-Virgin -2.40 -2.13 0507-Virgin -2.30 -2.13 -0.505



J - 113



RAP Virgin Kraton Polybuilt Existing HMA

Bulk Specific Gravity Gmb 2.3994 2.4263 2.4117 2.4037 2.3357

Maximum Specific Gravity Gmm 2.5173 2.5113 2.5113 2.5113 2.4747

Air Voids, % Va 4.68 3.38 3.97 4.28 5.62

Air Voids for Target Asphalt Content, % Va(design) 3.60 2.60 3.30 2.00 3.50

Total Asphalt Content by Weight, % Pb 4.77 5.13 5.10 5.00 5.53

Optimum/Saturation Asphalt Content, % Pb(0pt) 4.90 4.90 5.50 4.90 5.00

Aggregate Effective Specific Gravity Gse 2.710 2.719 2.718 2.713 2.690

Bulk Specific Gravity of Aggregate Blend Gsb 2.669 2.677 2.676 2.672 2.649

Effective Asphalt Content by Volume, % Vbe 9.693 10.627 10.506 10.239 11.086

Voids in Mineral Aggregate, % VMA 14.4 14.0 14.5 14.5 16.7Voids Filled with Asphalt, % VFA 67.4 75.8 72.6 70.5 66.4

Gradation Factor (GI Term) Kr3 0.40 0.40 0.40 0.40 0.40

Fine Aggregate Factor Findex 1.00 1.00 1.00 1.00 1.00

Coarse Aggregate Factor Cindex 1.00 1.00 1.00 1.00 1.00

Log Kr1 2.45 2.83 2.63 2.55 2.43

Rut Depth Coefficient kr1 -2.478 -2.132 -2.301 -2.375 -2.399

Temperature Exponent kr2 1.612 1.765 1.487 1.936 1.992

Traffic Loadings Exponent kr3 0.187 0.201 0.178 0.196 0.212

Asphalt Specific Gravity Gb 1.0393 1.0413 1.04 1.04 1.0457

Kr1 Value 281.83829 676.08298 426.57952 354.8134 269.1534804Absorbed Asphalt by Weight, % 0.6 0.6 0.6 0.6 0.6kr1 Log Value 9.3419918 20.752613 14.059469 11.86318 11.22563832

Montana SPS-5 Project




J - 114

J-7.10 Average Rut Depth Measurements Extracted from LTPP Database for the Montana SPS-5 Project


0502 29-Jul-90 -1.09 0.4720502 16-May-91 -0.30 0.6300502 08-Jun-96 4.77 0.3540502 02-Aug-96 4.92 0.3540502 22-May-98 6.73 0.4330502 09-Jun-99 7.78 0.4330502 25-Aug-99 7.99 0.4720502 25-Jul-00 8.90 0.4720502 06-Aug-01 9.94 0.0790502 29-Sep-01 10.08 0.0790502 01-Oct-03 12.09 0.0790502 13-May-04 12.71 0.079



0505 29-Jul-90 -1.09 0.4720505 16-May-91 -0.30 0.4720505 08-Jun-96 4.77 0.1970505 31-Jul-96 4.92 0.1970505 19-May-98 6.72 0.2360505 04-Jun-99 7.76 0.2360505 25-Aug-99 7.99 0.2360505 20-Jul-00 8.89 0.2760505 31-Jul-01 9.92 0.0790505 29-Sep-01 10.08 0.0790505 01-Oct-03 12.09 0.0790505 11-May-04 12.70 0.039


0506 29-Jul-90 -1.09 0.4720506 16-May-91 -0.30 0.5120506 08-Jun-96 4.77 0.3540506 31-Jul-96 4.92 0.3150506 20-May-98 6.72 0.3540506 07-Jun-99 7.77 0.3940506 25-Aug-99 7.99 0.5120506 20-Jul-00 8.89 0.4720506 31-Jul-01 9.92 0.0790506 29-Sep-01 10.08 0.0790506 01-Oct-03 12.09 0.0790506 11-May-04 12.70 0.079

0507 29-Jul-90 -1.09 0.3540507 17-May-91 -0.29 0.5510507 08-Jun-96 4.77 0.3540507 01-Aug-96 4.92 0.2760507 20-May-98 6.72 0.3150507 07-Jun-99 7.77 0.3540507 25-Aug-99 7.99 0.3540507 21-Jul-00 8.89 0.3940507 31-Jul-01 9.92 0.0790507 29-Sep-01 10.08 0.0790507 01-Oct-03 12.09 0.0790507 11-May-04 12.70 0.079





J - 115

0560 09-Jun-99 7.78 0.0790560 25-Aug-99 7.99 0.1570560 07-Aug-01 9.94 0.0790560 08-Jun-96 4.77 0.1180560 14-May-04 12.71 0.0390560 29-Sep-01 10.08 0.1180560 01-Oct-03 12.09 0.0790560 02-Aug-96 4.92 0.0790560 25-Jul-00 8.90 0.079

0561 25-Aug-99 7.99 0.1570561 14-May-04 12.71 0.0790561 01-Oct-03 12.09 0.0790561 29-Sep-01 10.08 0.0790561 25-Jul-00 8.90 0.1180561 09-Jun-99 7.78 0.0790561 22-May-98 6.73 0.0790561 02-Aug-96 4.92 0.0790561 08-Jun-96 4.77 0.1180561 06-Aug-01 9.94 0.079



J - 116

J-7.10 MEPDG Input Summary: Montana SPS-5 Test Section Example The following is a summary of the inputs for section 0504 that were used for the MEDPG runs using version NCHRP 9-30A version of the MEDPG.

Limit Reliability

55 170 90 5000 90 25 90 500 90 25 90 0.35 90 0.5 90 100

1800 2 50 100 60

Project: MT_SPS5_04 Westrack.dgp

General InformationDescription:This section is from the SPS-5 project in Montana and is section 04. It is a conventional HMA pavement on IH-90. The purpose of this run is to demonstrate the use of the MEPDG for predicting the performance of HMA overlays of flexible pavements. This is a thick overlay placed on existing HMA without milling. The HMA pavements along this SPS-5 project are 10 years old.

Design Life 9 yearsExisting pavement construction: September, 1982Pavement overlay construction: September, 1991Traffic open: September, 1991Type of design Flexible

Analysis Parameters


Location: SPS-5 ExperimentProject ID: IH-90Section ID: 30-0504 Principal Arterials - Interstate and Defense RoutesDate: 9/6/2007 Station/milepost format: Miles: 0.000Station/milepost begin: Station/milepost end: Traffic direction: East bound





J - 117


0.84 0.84 0.84 0.84 0.91 0.91 0.91 0.99 0.99 0.99 0.79 0.79 0.79 0.79 0.92 0.92 0.92 0.89 0.89 0.89 0.76 0.76 0.76 0.76 0.94 0.94 0.94 0.88 0.88 0.88 0.86 0.86 0.86 0.86 0.99 0.99 0.99 0.99 0.99 0.99 1.10 1.10 1.10 1.10 1.06 1.06 1.06 1.03 1.03 1.03 1.30 1.30 1.30 1.30 1.09 1.09 1.09 0.96 0.96 0.96 1.43 1.43 1.43 1.43 1.02 1.02 1.02 0.92 0.92 0.92 1.39 1.39 1.39 1.39 1.06 1.06 1.06 1.11 1.11 1.11 1.14 1.14 1.14 1.14 1.00 1.00 1.00 1.09 1.09 1.09 1.06 1.06 1.06 1.06 1.15 1.15 1.15 1.12 1.12 1.12 0.87 0.87 0.87 0.87 1.00 1.00 1.00 1.00 1.00 1.00 0.76 0.76 0.76 0.76 0.84 0.84 0.84 0.87 0.87 0.87

Midnight 2.3% Noon 5.9%

1.8% 1:00 am 2.3% 1:00 pm 5.9% 24.6% 2:00 am 2.3% 2:00 pm 5.9% 7.6% 3:00 am 2.3% 3:00 pm 5.9% 0.5% 4:00 am 2.3% 4:00 pm 4.6% 5.0% 5:00 am 2.3% 5:00 pm 4.6% 31.3% 6:00 am 5.0% 6:00 pm 4.6% 9.8% 7:00 am 5.0% 7:00 pm 4.6% 0.8% 8:00 am 5.0% 8:00 pm 3.1% 3.3% 9:00 am 5.0% 9:00 pm 3.1% 15.3% 10:00 am 5.9% 10:00 pm 3.1% 11:00 am 5.9% 11:00 pm 3.1%

3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5%

18 10 12

1.50 0.50 0.00 0.00 2.00 0.00 0.00 0.00 1.00 1.00 0.00 0.00 1.00 0.00 1.00 0.00 2.50 0.50 0.00 0.00 1.00 2.00 0.00 0.00 1.00 1.00 1.00 0.00 4.75 0.25 0.00 0.00 4.00 1.00 0.00 0.00 3.00 1.75 0.25 0.00

8.5 12 120 51.6 49.2 49.2


Vehicle ClassMonth





Vehicle Class

Growth Rate

GrowthFunction

Class 4 LinearClass 5 LinearClass 6 LinearClass 7 LinearClass 8 LinearClass 9 LinearClass 10 LinearClass 11 LinearClass 12 LinearClass 13 Linear




Vehicle Class

Single Axle

Tandem Axle

Tridem Axle

Quad Axle

Class 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12Class 13






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J-8 Texas SPS-5 Project

Construction Date: 9-25-1991 Elevation: 425 Route: US-175 Latitude: 32.61

Functional Class: 2 Longitude: -96.41 AADTT (Both Directions): 1220 Soil Type: Fat Inorganic

Clay The Texas SPS-5 project is located in Kaufman County just southeast of Dallas, Texas on US Route 175 in the southbound traffic lane. US Route 175 is a four-lane divided highway. J-8.1 Construction History The existing flexible pavement was built in 1987. The HMA overlay was placed in 1991 and opened to traffic in September 1991. Construction Issues: Project was initially delayed because of rain, mix design problems, and

receiving production plant parts. The air voids reported during construction are low, especially for the virgin mixture.

No maintenance or rehabilitation was applied to pavement within the monitoring period for measuring rut depths.

The SPS-5 project was taken out of service in September 2008. J-8.2 Pavement Cross Section The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table TX-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B).

Table TX-1. Summary of Average Layer Thickness from LTPP Database

Test Section

Layer Type and Thickness HMA Overlay Existing Pavement Layers



HMA Surface

HMA Binder

Lime Treated CS Base

Lime Treated

Subgrade 0502 RAP Mix 2.2 --- 1.3 7.9 14.6 8 0503 RAP Mix 2.1 3.2 1.4 8.0 12.4 8 0504 Virgin Mix 2.2 3.1 1.2 7.5 10.6 8 0505 Virgin Mix 2.0 --- 1.5 8.0 15.0 8

0506 Virgin

Mix/Mill 2.3 1.6 --- 7.7 15.0 8

0507 Virgin

Mix/Mill 2.0 5.0 --- 7.7 15.0 8

0508 RAP

Mix/Mill 2.1 5.2 --- 8.3 14.6 8

0509 RAP

Mix/Mill 2.2 2.1 --- 7.8 14.6 8

The leveling course or lift is combined with the binder layer thickness within the LTPP database. The thickness of the individual lifts placed during overlay construction varied from about 1.5 to 2.5 inches. Thus, the lift thicknesses initially measured from the trenches (discussed in a latter section of this report) did not agree with the LTPP database. Initially, this caused some concern and confusion on the specific layers of the overlay. After the leveling course was combined with the lower binder layer of the overlay, the thicknesses were much closer to those included in the



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LTPP database. All test sections are applicable and were included for comparing the different transfer functions and test procedures. J-8.3 Material Properties Reported during Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Those properties extracted from the LTPP database that were measured during construction and are being used to reconstitute the test specimens for the production test program are summarized below.

Aggregate Properties for HMA Overlay Mixtures: Type of aggregate included in the mixture design for both the RAP and virgin mixtures

for the binder layer was granite screening, granite coarse aggregate, and field sand. The aggregates used in the wearing surface were different. The following lists the aggregate percentages used to establish the job mix formula for all mixtures used within this SPS-5 project.


RAP Virgin

Binder & Leveling

Recycled HMA 35 0 Type D Crushed Granite 10 30 Type B Crushed Granite 33 23 Granite Screenings 10 30 Field Sand 12 17

Wearing Surface

Recycled HMA 35 0 Type D Trap Rock 10 23 Type C Trap Rock 28 27 Granite Screenings 15 31 Field Sand 12 19

Fine Aggregate Angularity – Not Reported Fine Aggregate bulk specific gravity – 2.620

o Specific gravity used for mixture design for the fine aggregate was 2.674 and 2.682.

Fine Aggregate Absorption (water) – 0.88 o Absorption of fine aggregate reported on the mixture design sheets was 0.3

percent. Coarse Aggregate Angularity – Not Reported Coarse Aggregate specific gravity – 2.763

o Specific gravity used for mixture design for the different coarse aggregate was 2.728 and 2.784.

Coarse Aggregate Absorption (water) – 0.55 o Absorption of coarse aggregate reported on the mixture design sheets varied from

0.2 to 0.4 percent.

Mixture #1—RAP Mixture and Test Sections: The mixture design sheets were reviewed and compared to the test results included in the LTPP database. Some significant deviations from the job mix formula (JMF) were noted for the RAP mixture. For example; the absorption values for the aggregate were found to be different, the LTPP gradation included much more fines that were outside the JMF specification limits, and the LTPP total asphalt content was much lower than designed in the



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laboratory. The values included in the LTPP database are being used to reconstitute the mixtures in the laboratory for production testing, which are listed below. Asphalt grade used in RAP mix – AC-5; Total Petroleum Anti-strip additive added to asphalt – 1.0 percent

o The tensile strength ratio (TSR) exceeded the minimum value of 0.70 with the anti-strip added to the asphalt.

Asphalt Specific Gravity – 1.031 o Much higher than included on the mix design sheets; 1.011.

Amount of RAP used in binder and surface – 35 percent Amount of asphalt in RAP material – 5 percent by weight RAP specific gravity – 2.482 Bulk specific gravity of aggregate blend – 2.671

o The bulk specific gravity of aggregate used in mixture design was 2.631 Effective specific gravity of aggregate – 2.702 Total asphalt content by weight – 4.1

o The target asphalt content to be added was 2.0 percent (for a coarser aggregate blend) which resulted in a total asphalt content (including the RAP material) of 3.8 percent.

Maximum Specific Gravity of RAP mix – 2.534 o The maximum specific gravity at the target asphalt content reported on the

mixture design sheet was 2.514. Voids in Mineral Aggregate – 13.0


Average Air Voids at construction – 4.42 Aggregate Blend for the RAP Mixture:

o The percent passing values for the smaller aggregate particles included in the LTPP database are significantly higher than the JMF. For example; the percent passing the #200 sieve was 1.7 percent, 7.3 percent for the #80 sieve, 33.2 percent for the #10 sieve, and 69.6 percent for the #3/8 sieve from the JMF. The following percent passing values are averages from the LTPP database.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Binder Mix 100 100 99 85 75 55 40 27.4 13.0 6.0 Surface No test data reported.

Mixture #2—Virgin Mixtures and Test Sections: Asphalt grade used in virgin mix – AC-10 with 3 percent latex (pre-

mixed) Anti-strip additive added to asphalt – 1.0 percent

o The TSR reported on the mixture design sheet with the anti-strip added to the asphalt was 0.66—less than the minimum value of 0.70. [NOTE: Refer to cores shown in the forensic investigation included in a latter part of this section. Cores show signs of stripping in the existing HMA and in lower lift of the HMA overlay.]

Asphalt Specific Gravity – 1.034 o Specific gravity from the mixture design sheet was 1.04.

Bulk specific gravity of aggregate blend – 2.694 Effective specific gravity of aggregate – 2.748 Total asphalt content by weight, % – 4.5

o The target asphalt content was 4.8 percent (for a coarser aggregate blend).



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Maximum Specific Gravity – 2.557 o The maximum specific gravity reported on the mix design sheets at the target

asphalt content was 2.505. Voids in Mineral Aggregate of virgin mix – 12.5


Average Air Voids at Construction – 2.66 Aggregate Blend for the Virgin Mixture:

o The percent passing values for the smaller aggregate particles included in the LTPP database are significantly higher than the JMF. For example; the percent passing the #200 sieve was 2.1 percent, 7.9 percent for the #80 sieve, 36.6 percent for the #10 sieve, and 72.4 percent for the #3/8 sieve from the JMF. The following percent passing values are averages from the LTPP database.

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Binder 100 100 98 91 80 57 43 27.3 14.3 6.4 Surface 100 100 100 83 73 51 39 27.0 11.7 5.6

Existing HMA Layer/Mixture:

Asphalt Specific Gravity – 1.056 Asphalt Content by Weight – 4.75 Maximum Specific Gravity – 2.439 Average Air Voids After Overlay Placement – 2.64 Aggregate Blend for the Two Layers/Mixtures, percent passing:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Binder 99 89 80 72 67 58 41 24.7 13.7 6.0 Surface 100 100 100 100 97 62 34 24.3 11.0 4.3

An important observation related to this project is that the viscosities recorded in the LTPP database during construction are high for the virgin mix—exceeding 300,000 poises. For this stiff asphalt, the rut depths should be minimal—which is not the case. J-8.4 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this tests section report. The maximum rut depths measured along the individual test sections varied from 0.236 (RAP mixture) to 0.472 (virgin mixture) inches—a significant difference between the test sections. Figure TX-1 shows the measured rut depths as a function of time for the two sections that were trenched, while figure TX-2 shows the measured rut depths as a function of time for all test sections within the SPS-5 project. As shown, mixture type (RAP versus virgin mixes) has a definite effect on the magnitude of the measured rut depths. Another important observation from this time-series data is the amount of variability in the measured rut depths for an individual test section.



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Figure TX-1. Average Maximum Rut Depths Measured with Time for Sections 48-A0507

(Mixtures without RAP) and A0508 (Mixtures with RAP)

Figure TX-2. Rut Depths Measured Over Time for each Test Section

The following lists the average maximum rut depths measured on the sections with the different HMA mixtures (RAP versus virgin mixes); the sections with the mixtures without RAP exhibited significantly higher rut depths.


Figure TX-3 shows the effect of HMA overlay thickness and mixture type on the maximum rut depth measured along each of the SPS-5 test sections. As shown, the test sections with the RAP mixtures have rut depths consistently less than those measured along the sections with the virgin mixtures. HMA overlay thickness has no impact or systematic effect on the rut depths for this

0.000

0.100

0.200

0.300

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0.500

0 2 4 6 8 10 12 14

Age, years

Ave

rag

e M

axim

um

Ru

t D

epth

, in

.

48-A0507, Virgin Mix 48-A0508, RAP Mix

0.0000.0500.100

0.1500.2000.2500.3000.350

0.4000.4500.500

0 2 4 6 8 10 12 14

Age, years

Me

as

ure

d R

ut

De

pth

, in

ch

es

48-0505,Virgin

48-0506,Virgin

48-0504,Virgin

48-0507,Virgin

48-0502,RAP

48-0509,RAP

48-0503,RAP

48-0508,RAP



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SPS-5 project. As noted above, the asphalt viscosities and penetration values recorded in the LTPP database for the virgin mixture suggest that this mixture is brittle and hard or stiff. The rut depths should be as low, if not lower than the RAP mixture, which is not the case. Thus, the Texas SPS-5 project was selected for the detailed forensic investigation.

Figure TX-3. Effect of HMA Overlay Thickness and Mixture Type on Maximum Rut

Depth J-8.5 Forensic Investigation of Texas SPS-5 Project Two trenches were excavated along this SPS-5 project to determine the amount of rutting within each HMA layer for a section with virgin mixtures and one with RAP mixtures. ARA engineers Paul Littleton and Harold Von Quintus were on site to collect pavement layer thickness measurements from the right wheel path of two SPS5 test sections; 48A507 and 48A508. ARA was assisted by Robert James of Burns Cooley Dennis, Inc. Trenching was originally excluded from the LTPP forensic investigation, but the Texas Department of Transportation (TexDOT) agreed with ARA that this information would be valuable for investigating the rutting behavior of these overlay mixtures. ARA and TexDOT excavated two trenches; one in a section with the RAP mixture and the other in a section with the virgin mixture. Dr. Feng Hong of TexDOT was on site to observe ARA take pavement layer measurements. Trench dimensions were 2 ft wide by 6 ft long positioned from the outer lane edge to the center of the lane. The trenches were excavated to the depth of the original pavement, approximately 7-inches. Figures TX-4 and TX-5 show the trenches within each section. Section 48A507 was designed to be a 5-in overlay comprised of 2-in virgin HMA surface course over a 3-in binder layer (figure TX-4). Section 48-A508 was designed to be a 5-in virgin HMA overlay comprised of 2-in surface course over 3-in binder (figure TX-5). Both sections were paved on top of a 2-in leveling course to smooth out roughness caused by milling.

0

0.1

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0 1 2 3 4 5 6 7 8


Ave

rag

e M

ax.

Ru

t D

epth

, in

.

Virgin Mixtures RAP Mixtures



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Six 6-in diameter cores were drilled by the Texas Transportation Institute (TTI) and recovered from both sections. These cores will be tested in the laboratory using the RSCH test to determine the effect of aging on the permanent deformation parameters and to determine the difference between the in place RAP and virgin mixtures. Figure TX-6 shows the cores that were recovered from section 48-A0507 (virgin mixture). The binder used in the virgin mixture was latex modified asphalt. Figure TX-7 shows the cores that were recovered from section 48-A-0508 (RAP mixture). Latex was not used within the binder for the RAP mixture, so it looks drier and exhibited much less rutting. Most of the cores were recovered intact but there were some that broke at the interface between the HMA overlay or leveling course and existing HMA surface (refer to figure TX-7). More importantly, some cores that were taken by TTI exhibited stripping and moisture damage during the wet coring operation (refer to figure TX-8). These were in other sections but do indicate that moisture damage was present in the existing HMA layers and/or lower lift of the HMA overlay. None of the HMA overlay mixtures, however, exhibited stripping or moisture damage during the coring process of the two sections where the trenches were excavated.

Figure TX-4. Trench Excavated Within Section 04-0507 (Virgin Mixture)

Figure TX-5. Trench Excavated Within Section

04-0508 (RAP Mixture)



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Measurements were taken from the pavement surface to a string line stretched taught across the surface of the pavement. Additional string lines were located at each interface between the HMA lifts. These string lines were used to easily locate the interface between the different lifts or layers. All layer thickness measurements were taken at the interface between the layers and not the string line itself. In most cases, the interface could be easily identified. Figure TX-9 shows the string lines in place and the equipment used to measure the layer thickness at different points across the face of the trench.

Figure TX-6. Photos of Cores Recovered from Sections 48-A0507 (Virgin Mixture)



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Figures TX-10 and TX-11 display the layer thickness profiles made within the trenches for sections 48-A0507 and 48-A0508, respectively. The thicknesses measured across the HMA overlay lifts are believed to be related to construction deviations. In other words, some of the thickness variations could be related to construction deviations, and it is certainly possible for the gradual change in thickness across the trench to have been caused by the crown settings of the screed, and/or lateral slope of the screed and screed extensions of the paver (refer to figure TX-11). Figures TX-12 and TX-13 show the individual layer thicknesses measured along the face of the trench, while figures TX-14 and TX-15 show the differential layer thicknesses measured along the cut face of the trench for both sections (0507 and 0508, respectively). As shown, the thickness profiles of the leveling course and first binder lift have opposite slopes in thickness versus paving width (refer to figure TX-13). This difference could have been caused by the crown settings of the paver. In other words, the paver could be correcting the slopes from one lift to another.

Figure TX-7. Photos of Cores Recovered from Sections 48-A0508 (RAP Mixture)



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Figure TX-8. Photo Showing the HMA Stripping that has Occurred in Localized Areas

within the Existing HMA Layer

Figure TX-9. Photos Showing the Layer Thickness Measurements within the Trench From these figures, it would appear that the rutting in section 48-A0508 is confined to the surface RAP layer, with a maximum of 0.25 in. Immeasurable rutting was found within the lower layers of the RAP overlay. For section 48A507, rutting has occurred within the surface layer of the virgin HMA with a maximum of about 0.2 in. centered in the wheel path, and continues into the bottom of the binder layer (leveling lift) to a magnitude of about 0.2 in. As noted previously, the lower lift of the virgin mix for binder layer or leveling course was reported to have tensile strength ratios (TSR) lower than the minimum required value of 0.70. Some of this rutting in the leveling course could be associated with moisture damage within that layer. The TSR values reported for the RAP mixtures all exceeded the minimum value of 0.70 and no measurable rut depths were found within that layer from the trench in section 48-A0508.



J - 132

0

1

2

3

4

5

6

0 12 24 36 48 60 72

Dep

th fr

om S

urf

ace,

in

Horizontal Distance from Center of Lane, in

Surface Binder 2nd Lift Binder 1st Lift Leveling Course

Figure TX-10. Section 48A507 Virgin HMA Overlay

0

1

2

3

4

5

6

0 12 24 36 48 60 72

Dep

th fr

om S

urf

ace,

in

Horizontal Distance from Center of Lane, in

Surface Binder 2nd Lift Binder 1st Lift Leveling Course

Figure TX-11. Section 48A508 RAP Overlay



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Figure TX-12. Layer or Lift Thickness Measurements Taken Along the Cut Face of the

Trench Excavated for Section 48-A0507 with the Virgin Mixture

Figure TX-13. Layer or Lift Thickness Measurements Taken Along the Cut Face of the

Trench Excavated for Section 48-A0508 with the RAP Mixture

1.000

1.200

1.400

1.600

1.800

2.000

2.200

0 10 20 30 40 50 60 70

Offset from Center of Lane, in.

Lay

er T

hic

knes

s, i

n.

Surface Lift Binder Lift Level-Up Lift

1.200

1.300

1.400

1.500

1.600

1.700

1.800

1.900

0 10 20 30 40 50 60 70


Lay

er T

hic

knes

s, i

n.

Wearing Lift Binder Lift Level-Up Lift



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Figure TX-14. Differential Layer Thickness Measured Along the Cut Face of the Trench

for Section 48-A0507 with the Virgin Mixture

Figure TX-15. Differential Layer Thickness Measured Along the Cut Face of the Trench

for Section 48-A0508 with the RAP Mixture In summary, most of the rutting has occurred within the HMA overlay wearing surface. It is difficult to determine the actual magnitude of rutting within each of the HMA overlay lifts for these two sections. Three lifts were placed for the overlay; the wearing surface, the binder layer and a leveling course. Table TX-1 excludes the leveling course that was placed prior to overlay, a separate layer. Based on an analysis of the measured rut depths, all measurable rutting has occurred in the

HMA overlay—most of the rutting has occurred within the wearing surface of both sections. Thus, both the RAP and virgin mixtures were tested because of the difference in magnitudes

-0.400

-0.300

-0.200

-0.100

0.000

0.100

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0.300

0 10 20 30 40 50 60 70


Dif

fere

nti

al L

ayer

Th

ickn

ess,

R

utt

ing

, in

.


-0.300

-0.200

-0.100

0.000

0.100

0.200

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Dif

fere

nti

al L

ayer

Th

ickn

ess,

R

utt

ing

, in

.




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of the rut depths. It is expected that immeasurable rutting has occurred in the existing HMA and other lower layers.

J-8.6 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA overlay reported in the LTPP database. The measured dynamic moduli were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E. J-8.7 Rut Depth Predicted with the Global Transfer Function Coefficients Figure TX-16 provides a comparison of the predicted and measured rut depths for all transfer functions using the global rut depth coefficients for the core test sections with and without RAP. Test sections 0502 and 0505 have similar pavement structures and have the thinner overlays, while sections 0507 and 0508 have the thicker HMA overlays. The comparison of the predicted and measured rut depths over time for the different rut depth transfer functions using the global plastic deformation coefficients was similar for the same mixture type and was independent of overlay thickness. In general, the Asphalt Institute transfer function over predicts the measured rut depths but exhibits a higher growth rate of rutting in comparison to the measured rut depth growth rate for the test sections that include mixtures with RAP. Conversely, the Verstraeten and MEPDG transfer functions consistently under predict the measured rut depths and exhibited a similar rut depth growth rate for the test sections that include mixtures with RAP. The WesTrack transfer function provided a closer simulation of the measured rut depths, as well as the rut depth growth rate for the test sections that included the mixtures with RAP. Figures TX-17 and TX-18 compare the measured and predicted rut depths using the global calibration values for the different transfer functions. As shown, the MEPDG and Verstraeten transfer functions consistently under predicts the rut depths—a negative bias. The Asphalt Institute transfer function consistently over predicts the rut depths, while the WesTrack transfer function generally had no bias for all of the test sections. Use of the NCHRP 1-40B mixture adjustment factors generally over predicted the rut depth for the without RAP mixtures and under predicted the rut depths measured on the with RAP mixtures. It is expected that the majority of the rutting has occurred in the HMA overlay mixtures, which was confirmed with the trenches.



J - 136

Figure TX-16. Comparison of the Predicted and Measured Rut Depths Using the Global

Coefficients for each Transfer Function for the Core Test Section in the Texas SPS-5 Project

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12 14 16

Age, years (Texas SPS 48-0502)

Ru

t D

epth

, in

ches

Verstraeten, Global

WesTrack, Global

MEPDG, Global



Measured Values

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12 14 16


Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12 14 16


Ru

t D

epth

, in

ches

Verstraeten, Global

WesTrack, Global

MEPDG, Global



Measured Values

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12 14 16


Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12 14 16


Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

0

0.1

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0.3

0.4

0.5

0 2 4 6 8 10 12 14 16

Age, years (Texas Section 48-0508)

Ru

t D

epth

, in

ches

Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

0

0.1

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Ru

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epth

, in

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Verstraten, Global


WesTrack, Global


MEPDG, Global

Measured Values

0

0.1

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Ru

t D

epth

, in

ches

WesTrack, Global

Verstraeten, Global

MEPDG, Global



Measured Values



J - 137

Figure TX-17. Comparison of the Predicted and Measured Rut Depths for the Global

Calibration Values for the MEPDG, Asphalt Institute, and Verstraeten Transfer Functions

0

0.05

0.10.15

0.2

0.25

0.3

0.350.4

0.45

0.5

0 0.1 0.2 0.3 0.4 0.5

Measured Rut Depth, inches

Pre

dic

ted

Ru

t D

epth

(G

lob

al

ME

PD

G),

in

ches

RAP TestSections

Virgin Sections

Line of Equality

Linear (RAPTest Sections)

Linear (VirginSections)

0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.1 0.2 0.3 0.4 0.5 0.6


Pre

dic

ted

Ru

t D

epth

, A

sph

alt

Inst

itu

te,

Glo

bal

, in

ches RAP Test

Sections

Virgin Sections

Line of Equality



0

0.1

0.2

0.3

0.4

0.5

0 0.1 0.2 0.3 0.4 0.5

Measured Rut Depth, inhes

Pre

dic

ted

Ru

t D

epth

, V

erst

rate

n,

Glo

bal

, in

ches

RAP TestSections

Virgin Sections

Line of Equality





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Figure TX-18. Comparison of the Predicted and Measured Rut Depths for the Global

Calibration Values for the WesTrack Transfer Function and the MEPDG using the NCHRP 1-40B Mix Adjustment Factors

Figure TX-19(a) compares the measured and predicted rut depths using the global calibration values for the different MEPDG transfer functions for some of the mixtures with and without RAP. A comparison of the residual errors and predicted rut depths is shown in figure TX-19(b). As shown, there is significant deviation between the measured and predicted rut depths and the residual error is highly variable. Figure TX-20 compares the predicted and measured rut depths using the NCHRP 1-40B mixture adjustment factors, as well as comparing the predicted rut depths to the residual errors. As shown, most of the bias resulting from the global values (refer to figure TX-19) has been removed and the standard error was reduced; BUT—there is still a negative bias between the measured and predicted values.

0

0.1

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0.3

0.4

0.5

0 0.1 0.2 0.3 0.4 0.5

Measured Rut Depths, inches

Pre

dic

ted

Ru

t D

epth

s (W

esT

rack

, G

lob

al),

in

ches

RAP TestSections

Virgin Sections

Line of Equality



0

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0.4

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0.6

0 0.1 0.2 0.3 0.4 0.5 0.6


Pre

dic

ted

Ru

t D

epth

, 1-

40B

Mix

A

dju

stm

ent

Val

ues

, in

ches

RAP TestSections

Virgin Sections

Line of Equality

Linear (RAP TestSections)




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Figure TX-19. Comparison of the Predicted and Measured Rut Depths and Residual Error

Using the MEPDG Global Calibration Values for the SPS-5 Project

0

0.1

0.2

0.3

0.4

0.5

0.000 0.100 0.200 0.300 0.400 0.500

Measured Rut Depth, in.

Pre

dic

ted

To

tal

Ru

t D

epth

, in

.

RAP Mixtures Virgin Mixtures Line of Equality

-0.400-0.350-0.300-0.250-0.200-0.150-0.100-0.0500.0000.050

0 0.05 0.1 0.15 0.2

Predicted Total Rut Depth, in.

Re

sid

ua

l E

rro

r (P

red

icte

d

Min

us

Me

as

ure

d V

alu

es

),

in.

48-0505 48-0507 48-0502 48-0508

(b) Predicted versus residual errors.

(a) Measured versus predicted rut depths.



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Figure TX-20. Comparison of the Predicted and Measured Rut Depths and Residual Error

Using the NCHRP 1-40B Mix Adjustment Values for the SPS-5 Sections

J-8.8 Field-Derived Coefficients of the Transfer Functions This section summarizes the comparison of the predicted and measured rut depths using laboratory permanent deformation test results in support of the different rut depth transfer functions. Table TX-2 summarizes the field-derived coefficients of each transfer function and test section, while Figures TX-21 and TX-22 compare the predicted and measured rut depth for the test sections with and without RAP, respectively. Sections 0502 and 0508 represent the thinner and thicker HMA overlay with RAP, while sections 0505 and 0507 represent the thinner and thicker HMA overlays without RAP. As shown, each transfer function accurately predicted the measured rut depths. The test sections with and without milling exhibited a similar comparison between the measured and predicted rut depths. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section. The exponent to the number of load cycle term and intercept of the transfer functions will be used to evaluate differences between the laboratory-derived and field-derived coefficients.

0

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0.000 0.100 0.200 0.300 0.400 0.500


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dic

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Virgin Mixtures RAP Mixtures Line of Equality

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-0.200

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0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Predicted Rut Depth, in.

Res

idu

al E

rro

r, i

n.

Virgin Mixture RAP Mixture



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Figure TX-21. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0505 and 0507; Mixtures

without RAP



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Figure TX-22. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0502 and 0508; Mixtures

with RAP

Table TX-2. Field-Derived Slope and Intercept


1-40B Modified


Slope

Mixes with RAP

0.25 0.30 0.25 0.25 0.25

Mixes without RAP

0.35 0.33 0.35 0.35 0.35

Intercept

0502-RAP -1.791 -2.585 -0.345 685 1.968 0503-RAP -1.785 2.585 -0.151 137 1.80 0508-RAP -1.651 -2.585 -0.144 135 1.85 0509-RAP -1.904 -2.585 -0.014 213 1.81 0504-Virgin -2.290 -1.79 -0.344 244 1.179 0505-Virgin -2.111 -1.79 -0.295 573 0.881 0506-Virgin -2.26 -1.79 -0.314 201 1.243 0507-Virgin -2.00 -1.79 -0.459 145 1.15



J - 143



RAP Mix Virgin Mix RAP Mix Virgin Mix Binder Surface

Bulk Specific Gravity Gmb 2.422 2.489 2.422 2.489 2.3577 2.3916

Maximum Specific Gravity Gmm 2.534 2.5567 2.534 2.5193 2.412 2.4657

Air Voids, % Va 4.42 2.65 4.42 1.20 2.25 3.01

Air Voids for Target Asphalt Content, % Va(design) 4.00 4.00 4.00 4.00 4.00 4.00

Total Asphalt Content by Weight, % Pb 4.10 4.50 4.10 5.00 4.70 4.80

Optimum/Saturation Asphalt Content, % Pb(0pt) 4.50 4.50 4.80 5.20 4.70 4.80

Aggregate Effective Specific Gravity Gse 2.702 2.747 2.702 2.724 2.576 2.642

Bulk Specific Gravity of Aggregate Blend Gsb 2.671 2.715 2.671 2.692 2.548 2.613

Effective Asphalt Content by Volume, % Vbe 8.618 9.798 8.618 10.964 9.572 9.863

Voids in Mineral Aggregate, % VMA 13.0 12.4 13.0 12.2 11.8 12.9Voids Filled with Asphalt, % VFA 66.1 78.7 66.1 90.1 81.0 76.6

Gradation Factor (GI Term) Kr3 0.70 0.70 0.70 0.70 0.70 0.40

Fine Aggregate Factor Findex 1.05 1.05 1.05 1.05 1.00 1.00

Coarse Aggregate Factor Cindex 0.90 0.90 0.90 0.90 1.00 1.00

Log Kr1 2.40 2.95 2.43 3.80 3.10 3.80

Rut Depth Coefficient kr1 -2.593 -2.103 -2.563 -1.382 -2.000 -1.221

Temperature Exponent kr2 1.346 1.330 1.242 1.040 1.352 1.453

Traffic Loadings Exponent kr3 0.306 0.335 0.286 0.322 0.335 0.192

Asphalt Specific Gravity Gb 1.031 1.034 1.031 1.038 1.052 1.06

Kr1 Value 251.18864 891.25094 269.15348 6309.5734 1258.925412 6309.5734Absorbed Asphalt by Weight, % 0.45 0.45 0.45 0.45 0.45 0.45kr1 Log Value 7.1772552 22.18262 7.69056749 116.53961 28.1256691 168.88162

Existing Layers

NOTE: Bulk specific gravities were not reported in the LTPP database for the wearing surface of the sections with the RAP and virgin mixtures. It was simply assumed that the bulk specific gravities would be similar to those of the binder and level up layers. In addition, maximum specific gravities were not reported for the wearing surface of the RAP mixtures or test sections.

Layer IdentificationBinder Layer Wearing Surface

NOTE: An anti-strip additive of 1 percent was added to the asphalt, but the Virgin mixture exhibited signs of stripping in a few cores and the mix design sheets reported a TSR value of 0.66 for the virgin mixture and 0.79 for the RAP mixture. The minimum value required was 0.70.

Texas SPS-5 Project - Binder and Surface Layers

Note: The mixture design information was not used to determine the saturation asphalt content,

because of the difference in gradation between the values included in the LTPP database and mix design sheets. The value included above was based on other designs and information for the granite aggregate with a finer aggregate blend.



J - 144

J-8.10 Average Rut Depth Measurements Extracted from LTPP Database for the Texas SPS-5 Project


48-0505. 28-Jan-92 0.4 0.07948-0505. 03-Mar-93 1.5 0.15748-0505. 09-Mar-95 3.5 0.27648-0505. 04-Jun-98 6.8 0.27648-0505. 05-Nov-99 7.2 0.23648-0505. 27-Apr-00 7.4 0.31548-0505. 16-May-01 8.4 0.31548-0505. 10-Jan-02 9.3 0.31548-0505. 05-Apr-02 9.5 0.39448-0505. 24-Apr-03 10.5 0.35448-0505. 02-Dec-03 11.2 0.23648-0505. 17-Mar-04 11.5 0.35448-0505. 09-Mar-05 12.5 0.354


48-0504. 28-Jan-92 0.4 0.07948-0504. 03-Mar-93 1.5 0.19748-0504. 09-Mar-95 3.5 0.23648-0504. 03-Jun-98 6.8 0.31548-0504. 05-Nov-99 7.2 0.27648-0504. 26-Apr-00 7.4 0.31548-0504. 16-May-01 8.4 0.35448-0504. 10-Jan-02 9.3 0.27648-0504. 05-Apr-02 9.5 0.43348-0504. 23-Apr-03 10.5 0.35448-0504. 02-Dec-03 11.2 0.27648-0504. 17-Mar-04 11.5 0.354









J - 145

J-8-11 MEPDG Input Summary: Texas SPS-5 Test Section Example The following is a summary of the inputs that were used for the MEDPG runs using NCHRP 9-30A version of the software. These are provided as an example to document the data and information included for this SPS-5 project. One note, the traffic input values were not included in the LTPP database for this project. The AADTT input value was determined from other information provided by Texas DOT on this segment of highway.


1220 2 55 95 55

Project: NCHRP1-40B_Texas SPS-502

General Information Description:SPS-5Design Life 14 years

Existing pavement construction: June, 1977Pavement overlay construction: September, 1991Traffic open: September, 1991Type of design Flexible

Analysis Parameters


Location: Kaufman County, TexasProject ID: SPS-5Section ID: A0502 Principal Arterials - OthersDate: 3/2/2008 Station/milepost format: Miles: 0.000Station/milepost begin: Station/milepost end: Traffic direction: East bound





J - 146


1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00


3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5%

18 10 12

1.62 0.39 0.00 0.00 2.00 0.00 0.00 0.00 1.02 0.99 0.00 0.00 1.00 0.26 0.83 0.00 2.38 0.67 0.00 0.00 1.13 1.93 0.00 0.00 1.19 1.09 0.89 0.00 4.29 0.26 0.06 0.00 3.52 1.14 0.06 0.00 2.15 2.13 0.35 0.00

8.5 12 120 51.6 49.2 49.2


Vehicle ClassMonth





Vehicle Class

Growth Rate

GrowthFunction





Quad Axle


Vehicle Class

Single Axle

Tandem Axle

Tridem Axle







J - 147

32.62 -96.43 425 12

-10 -16 -22 -28 -34 -40 -46

LoadTime(sec)

LowTemp.-4ºF

(1/psi)

Mid.Temp.14ºF

(1/psi)

HighTemp.32ºF

(1/psi) 1 3.28E-07 4.15E-07 5.26E-07 2 3.48E-07 4.68E-07 6.35E-07 5 3.76E-07 5.5E-07 8.15E-07 10 3.99E-07 6.2E-07 9.85E-07 20 4.24E-07 7E-07 1.19E-06 50 4.59E-07 8.22E-07 1.53E-06 100 4.87E-07 9.28E-07 1.84E-06

Climate icm file:

C:\DG2002\Projects\Texas SPS-5.icm Latitude (degrees.minutes)Longitude (degrees.minutes)Elevation (ft)Depth of water table (ft)











High temp.°C


46525864707682




J - 148






Asphalt MixCumulative % Retained 3/4 inch sieve: 20Cumulative % Retained 3/8 inch sieve: 33Cumulative % Retained #4 sieve: 43% Passing #200 sieve: 6




J - 149

Value 7.2555 1.3328 0.82422 117.4

Layer 3 -- Crushed stoneUnbound Material: Crushed stoneThickness(in): 14.6

Strength PropertiesInput Level: Level 3Analysis Type: Representative value (User Input Modulus)Poisson's ratio: 0.35Coefficient of lateral pressure,Ko: 0.5Modulus (input) (psi): 30000Moisture Content(%): -9999



#200 8.7#100 #80 12.9#60 #50 #40 20#30 #20 #16 #10 33.8#8 #4 44.7

3/8" 57.21/2" 63.13/4" 72.71" 78.8

1 1/2" 85.82" 91.6

2 1/2" 3"

3 1/2" 97.64" 97.6



Parametersabc

Hr.



J - 150

Value 7.2555 1.3328 0.82422 117.4

Layer 4 -- Crushed gravelUnbound Material: Crushed gravelThickness(in): 8




#200 8.7#100 #80 12.9#60 #50 #40 20#30 #20 #16 #10 33.8#8 #4 44.7

3/8" 57.21/2" 63.13/4" 72.71" 78.8

1 1/2" 85.82" 91.6

2 1/2" 3"

3 1/2" 97.64" 97.6



Parametersabc

Hr.



J - 151

Value 7.2555 1.3328 0.82422 117.4

Layer 4 -- Crushed gravelUnbound Material: Crushed gravelThickness(in): 8




#200 8.7#100 #80 12.9#60 #50 #40 20#30 #20 #16 #10 33.8#8 #4 44.7

3/8" 57.21/2" 63.13/4" 72.71" 78.8

1 1/2" 85.82" 91.6

2 1/2" 3"

3 1/2" 97.64" 97.6



Parametersabc

Hr.



J - 152

0.007566 1 3.9492 1 1.281 1

1 1

-3.35412 1.5 1.5606 1 0.4791 1.15

1.5 1

1 1

2.03 0.75 1.35 0.75

7 3.5 0 1000 1 1 0 6000

1 1 0 1000

40 0.4 0.008 0.015 0 0 0 0

Distress Model Calibration Settings - Flexible AC Fatigue Level 4 (Regionally calibrated values)

k1Bf1k2Bf2k3Bf3


AC Rutting Level 4 (Regionally calibrated values)k1Br1k2Br2k3Br3


0.24*POWER(RUT,0.8026)+0.001

Thermal Fracture Level 4 (Regionally calibrated values)k1Bt1



k1k2

Subgrade Rutting Level 4 (Regionally calibrated values)Granular:

k1Bs1

Fine-grain:k1Bs1










C4(HMA/PCC)




J - 153

J-9 Wisconsin SPS-1 and SPS-9 Projects

Construction Date: 10-1-1997 Elevation: 1239 Route: 29 Latitude: 44.87

Functional Class: 14 Longitude: 89.29 AADTT (LTPP Lane Only): 520 Soil Type: Silty Sandy

The SPS-1 and SPS-9 projects are located just southeast of Wausau, Wisconsin on US Route 29 in the westbound traffic lane. US Route 29 is a four-lane divided highway. J-9.1 Construction History Sections were built and opened to traffic in 1997. No construction difficulties were reported

or noted in the construction report. No maintenance or rehabilitation was applied to pavement within the monitoring period for

measuring rut depths. The SPS-1 and SPS-9 projects were taken out of service in September 2008. The wearing

surface was milled to a depth of 1.5 inches and replaced with a 2.0 HMA overlay. The second overlay had been placed one week prior to the forensic investigation.

J-9.2 Pavement Cross Section Multiple test sections were included in rutting comparisons. The sections with and without the asphalt treated base and permeable asphalt treated base layers were included in the analysis. The layer thicknesses were extracted from the LTPP database, along with the volumetric data at the time of construction. Table WS-1 summarizes the pavement cross section for each test section (from LTPP Data Table L05B).

Table WS-1. Summary of Average Layer Thickness from LTPP Database Test

Section Layer Type and Thickness, inches

Wearing Surface

Binder Layer

ATB PATB Crushed Stone Base

Granular Subbase

Embank.

SPS-1 Project 55-0113 1.9 3.6 8.0 24.0 55-0114 1.7 6.4 11.0 10 55-0115 2.0 5.3 7.5 1.8 10 55-0116 2.1 2.0 12.0 0.8 10 55-0117 1.9 4.5 4.6 5.0 10 55-0118 1.9 2.1 8.9 5.2 10 55-0119 2.0 4.6 3.4 5.8 10 55-0120 1.8 2.1 4.8 8.7 10 55-0121 2.1 2.1 4.2 13.3 6.8 55-0122 1.9 2.6 4.8 4.9 4.8 10 55-0123 1.9 4.9 8.1 4.3 7.8 55-0124 1.9 5.2 11.7 3.3 8.0

SPS-9 Project 55-C901 2.0 7.8 13.0 24.0 55-C902 2.0 6.9 13.0 5.0 55-C903 2.0 7.2 13.0 5.0 55-C959 1.6 7.2 13.0 24.0 55-C960 1.9 6.4 13.0 5.0

All test sections, excluding those with the Permeable Asphalt Treated Base (PATB) layer, are applicable and were included for comparing the different transfer functions and test procedures. However, the layer thicknesses measured within the two sections that were trenched were found to be significantly thicker than included in the LTPP database.



J - 154

J-9.3 Material Properties Reported during Construction The average properties used in the rut depth predictions with the MEPDG are summarized at the end of this test section report. Those properties extracted from the LTPP database that were measured during construction and used to reconstitute the test specimens for the production testing program are summarized below. [The mixture designs for the different layers or mixtures were requested but unavailable for review from this project.]

Asphalt Properties: Asphalt Grade Used in SPS-1 Mixtures – PG 58-28; AMACO Pen 85-100 with

anti strip additive Asphalt Grade Used in SPS-9 Mixtures – PG 58-34; AMACO 85-100 with anti-

strip additive Asphalt Specific Gravity – 1.063

Aggregate Properties: Fine Aggregate Angularity – 42 (40 to 43) Fine Aggregate bulk specific gravity – 2.643 Fine Aggregate Absorption (water) – 0.58 Coarse Aggregate Angularity – No data recorded in the LTPP

database. Coarse Aggregate specific gravity – 2.639 Coarse Aggregate Absorption (water) – 0.69

Wearing Surface: Total asphalt content by weight – 6.2 Maximum Specific Gravity – 2.4567 Average Air Voids (SPS-1 Sections) – 6.5 Average Air Voids (SPS-9 Sections) – 6.8 Aggregate Blend for the Wearing Surface Mixture:


Binder Layer: Total asphalt content by weight – 5.8 Maximum Specific Gravity – 2.4563 Average Air Voids (SPS-1 Sections) – 6.3 Average Air Voids (SPS-9 Sections) – 5.6 Aggregate Blend for the Binder Mixture:


ATB (Asphalt Treated Base) Layer: Total asphalt content by weight – 4.4 Maximum Specific Gravity – 2.499 Average Air Voids (SPS-1 Sections) – 6.5 Aggregate Blend for the ATB Mixture:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Passing, % 100 99 92 65 53 37 29 10.7 5.3 3.0



J - 155

PATB (Permeable Asphalt Treated Base) Layer: Total asphalt content by weight – 2.0 Maximum Specific Gravity – 2.591 Average Air Voids (SPS-1 Sections) – 13.8 Aggregate Blend for the PATB Mixture:

Sieve Size 1 ½ 1 ¾ ½ 3/8 #4 #10 #40 #80 #200 Passing, % 100 100 99 62 36 8.0 5.5 4.5 4.0 3.3

J-9.4 Analysis of Measured Rut Depths The average rut depths measured over time and extracted from the LTPP database for each test section are included at the end of this test section forensic report. The maximum rut depths measured along the individual test sections varied from 0.113 to 0.413 inches—a significant difference between the test sections. The SPS-9 sections exhibited the smaller rut depths, while the SPS-1 sections with an ATB layer consistently exhibited the larger rut depths. No ATB was placed within the SPS-9 sections. Figure WS-1 shows the measured rut depths as a function of total HMA thickness, excluding the PATB layer. As shown, the maximum rut depth measured within a test section appears to be related to the total HMA thickness—rut depth increases with increasing HMA thickness. On other projects, it has been observed that the maximum rut depth decreases with increasing HMA thickness to some maximum value when the rut depth remains relatively constant. Conversely, figure WS-2 shows the maximum rut depth versus total HMA thickness but stratified between test sections with and without an ATB layer. As shown, the test sections with the ATB layer consistently exhibited the higher rut depths. The effect of HMA thickness on rut depth is less defined when grouping the rut depths by layer or structure type (with and without ATB layer). In fact, the maximum rut depth measured at each test section is independent of HMA thickness when grouping the data by test sections with and without an ATB layer. The following lists the average maximum rut depths measured on the sections with and without the ATB layer.

Statistical Parameter With ATB Layer Without ATB Layer Mean Max. Rut Depth, in. 0.359 0.183 Standard Deviation, in. 0.0605 0.0576 Coefficient of Variation, % 16.9 31.4



J - 156

It was the Wisconsin DOT’s opinion that the rut depths have occurred in the foundation materials, while from another project it was the opinion that the rutting was primarily in the surface or binder layers. The maximum rut depths were also compared between test sections with different types of materials to determine whether the PATB and/or aggregate base layers have contributed to the change in rut depths. Figure WS-3 shows the measured rut depths over time for the two sections that were trenched, while figure WS-4 shows the rut depths measured over time for all test sections within the SPS-1 project. Figure WS-5 shows the rut depths measured along the SPS-9 sections over time. The maximum rut depths measured along a specific test section were not related to the crushed stone aggregate base or the PATB layers. Two types of soils were reported along the SPS-1 and SPS-9 projects, but the rut depths were not consistently higher or lower for each soil type. From this preliminary analysis, it was hypothesized that minimal rutting has occurred in the subgrade, embankment, and crushed stone base layer, while most of the rutting was exhibited in the ATB layer (refer to figure WS-2). Thus, the Wisconsin SPS-1 project was selected for a detailed forensic investigation—trenches were planned to confirm that hypothesis. J-9.5 Forensic Investigation of SPS-1 Project Two trenches were excavated to collect pavement layer thickness measurements from recently milled and overlaid SPS1 test sections 55-0113 and 55-0116 along US 29, approximately 0.5 mile east of Hatley, Wisconsin. As summarized in table WS-1, section 0113 has the thinner HMA and no ATB layer, while section 0116 has a thick ATB layer. The maximum rut depth recorded along section 0113 was 0.226 inches, while the maximum rut depth for section 0116 was 0.413 inches.

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 5 10 15 20

Total HMA Thickness, Excluding PATB, in.

Max

imu

m R

ut

Dep

th,

in.

00.050.1

0.150.2

0.250.3

0.350.4

0.45

0 5 10 15 20

Total HMA Thickness, Excluding PATB, in.

Max

imu

m R

ut

Dep

th,

in.

Without ATB Layer With ATB Layer

Figure WS-1. Maximum Rut Depth Related to Total HMA Thickness of Dense-Graded

Mixtures

Figure WS-2. Maximum Rut Depth Related to Total HMA Thickness of Dense-Graded Mixtures Stratified By Test

Sections With and Without an ATB Layer



J - 157

Figure WS-3. Average Maximum Rut Depths Measured Over Time for Sections 55-0113

and 55-0116

Figure WS-4. Rut Depths Measured Over Time for the Wisconsin SPS-1 Test Sections

0.000

0.100

0.200

0.300

0.400

0.500

0 2 4 6 8 10

Age, years

Ru

t D

epth

, in

ches

Section 0113, No ATB Layer Section 0116, 12-inch ATB Layer

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0 2 4 6 8 10

Age, years

Ave

rag

e M

ax. R

ut

Dep

th, i

n.

55-0113, No PATB

55-0114, No PATB

55-0119, With PATB

55-0120, With PATB

550121, With PATB

0.0000.0500.1000.1500.200

0.2500.3000.3500.4000.450

0 2 4 6 8 10

Age, years

Ave

rag

e M

ax. R

ut

Dep

th,

in.

55-0115, No PATB

55-0116, No PATB

55-0117, No PATB

55-0118, No PATB

55-0122, With PATB

55-0123, With PATB

55-0124, With PATB

(a) Sections without an ATB layer.

(b) Sections with an ATB layer.



J - 158

Figure WS-5. Rut Depths Measured Over Time for the Wisconsin SPS-9 Test Sections—

Includes PMA Mixtures; No ATB and No PATB Layer Trenching was initially attempted by the Marathon County Highway Department until it was determined that the HMA layers were much thicker than recorded in the LTPP database. ARA was assisted by Robert James of Burns Cooley Dennis who arranged for pavement cutting the thicker layers by Central Concrete Cutting, Inc. The trench dimensions were 5 ft wide by 6 ft long and 2 ft deep positioned across the right wheel path of the LTPP or driving lane. Blocks of HMA and ATB layers were extracted for laboratory testing from section 0116. The purpose of these blocks are to use the RSCH test to measure the permanent deformation parameters of the ATB and binder layers to determine the effect of aging on those parameters and measure the difference between the parameters for the in place materials. The first trench cut was about 50 feet within section 0113. The thickness of the bituminous layers was found to be significantly different than recorded in the LTPP database. In fact, a thickness of nearly 14 inches was measured along one of the cut faces. Figure WS-6 shows the photos taken during the sawing operation and trying to remove the HMA. The saw originally requested for this trenching operation was insufficient to cut through the entire HMA layer. A hydraulic hammer was used to penetrate the HMA thickness in an effort to remove the HMA, but without success as shown in figure WS-6. The trenching operation was stopped once the thickness of the HMA was determined to be significantly thicker than expected. Rain within the area also caused the operation to be suspended until a later date. It is important to note that the hydraulic hammer could easily penetrate the HMA overlay that had been recently placed and the existing HMA binder layer. However, the sound of the hammer changed once it reached the level of the crushed stone base layer (or what was supposed to be the crushed stone base). The penetration rate of the machine was significantly reduced, indicating a much harder material. After portions of the surface layers were removed, it was observed that the crushed stone had been treated with some type of bituminous material—it did not appear to be the asphalt treated base layer which was observed through a full-depth core taken in section 0116 (refer to figures WS-7 and WS-8). The thickness of the core was nearly 19 inches—the average thickness recorded in the LTPP database for this section (55-0116) was 16 inches.

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0 2 4 6 8 10

Age, years

Ave

rag

e M

ax.

Ru

t D

epth

, in

ches

C901

C902

C903

C959

C960



J - 159

Figure WS-6. Photos of the Trenching Operations for Section 55-0113 Deflection data were not reviewed prior to the trenching operation. The deflection data were reviewed after the thickness and material discrepancy was found. This deflection data will be discussed in the next section of the test section report. The second trench (section 55-0116) was excavated at a later date with the use of a much larger saw. Figure WS-7 shows images of the trenching operations and figure WS-8 shows the cross section of the pavement and the open trench. The HMA layers were found to be slightly thicker than recorded in the LTPP database.



J - 160

Figure WS-7 Trench operations in section SPS1 55-0116 near Hatley, Wisconsin.

Figure WS-8. Cross Section of the Trench and the Open Trench; 55-0116

Section 55-0116 was recently milled 1.5 inches and overlaid in September, 2008 with a 2.0 inch HMA wearing surface mixture eliminating all evidence of rutting. Discussions with Marathon County Highway Department personnel confirmed the level of rutting recorded in the LTPP database prior to the recent overlay. Lift thickness profiles were taken from a string line stretched taught across the surface of the pavement and along each lift (refer to figure WS-8). The string line was used to easily locate the interface between the different lifts or layers. All layer thickness measurements were taken at the



J - 161

interface between the layers and not the string line itself. In most cases, the interface could be identified. Figure WS-9 shows only the upper pavement layer thicknesses to emphasize the rutting in the right wheel path, while figure WS-10 shows the entire depth. Figures WS-9 and WS-10 suggests that most of the rutting has occurred in the HMA binder and top lift of the ATB layer. No measurable rutting was found below the first ATB lift. Thus, all measurable rutting was found within the top 6 to 7 inches. It should be noted that the surface layer includes the HMA overlay recently placed and a portion of the original HMA wearing surface. The transition between the HMA overlay and existing wearing surface was not recorded. The individual layer thickness profiles are shown in figure WS-11 for the binder layer and in figure WS-12 for the ATB. The thicknesses measured across the HMA binder layer are believed to be more related to construction deviations, while the thickness measured across the ATB layer shows a gradual reduction in layer thickness from under the wheel path. Some of the thickness variations, however, could be related to construction deviations, and it is certainly possible for the gradual thickness reduction to have been caused by the crown settings of the screed, and/or lateral slope of the screed and screed extensions of the paver. Figure WS-13 shows the differential layer thicknesses measured along the cut face of the trench. This differential thickness profile suggests some rutting in the HMA binder layer, while most of the rutting occurred in the upper ATB layer. The construction reports and documents do not indicate how many ATB lifts were placed during construction—however, three lifts were observed on the face of the cut. Based on an analysis of the measured rut depths, three mixtures should be tested: the ATB,

the thicker conventional-neat dense-graded binder layer, and the PMA mixture placed along the SPS-9 project that exhibited minimal rutting. Unfortunately, there is an insufficient amount of PMA mixture and binder in the MRL to complete all of the NCHRP 9-30A production testing. Materials were requested and ordered from the other two layers (dense-graded HMA binder layer and the ATB).



J - 162

Figure WS-9. Layer or Lift Thickness Measurements Taken Along the Cut Face of the

Trench Excavated for Section 0116 for the HMA Layers.


Trench Excavated for Section 0116 for all Layers

0

1

2

3

4

5

6

7

8

9

10

6 12 18 24 30 36 42 48 54 60 66 72


Dep

th f

rom

Su

rfac

e, in

Surface Binder ATB ATB

0

5

10

15

20

6 12 18 24 30 36 42 48 54 60 66 72


Dep

th f

rom

Su

rfac

e, in

Surface Binder ATB ATB ATB Subgrade



J - 163


Trench Excavated for Section 0116 for the HMA Binder Layer


Trench Excavated for Section 0116 for the ATB Layer

1.900

1.950

2.000

2.050

2.100

2.150

2.200

2.250

0 10 20 30 40 50 60 70 80

Offset from Lane Centerline, in.

Lay

er T

hic

knes

s, i

n.

Binder Layer

13.60

13.70

13.80

13.90

14.00

14.10

14.20

14.30

14.40

14.50

14.60

0 10 20 30 40 50 60 70 80

Offset from Lane Centerline, in.

AT

B L

ayer

Th

ickn

ess,

in

.

ATB Layer



J - 164

Figure WS-13. Differential Layer Thickness Measured Along the Cut Face of the Trench

for Section 0116 J-9.6 Deflection Profiles After the thickness discrepancy was found along section 55-0113, the deflection basin data were extracted and reviewed from the LTPP database. Figure WS-14 shows the change in different deflection values measured over time.

Figure WS-14(a) shows the deflections measured by sensor #1 of the FWD. As shown, there is a 50 percent reduction in the sensor #1 deflection between the first and second dates for section 0113; while no significant reduction was found along section 0116. This level of reduction in the sensor #1 deflections for section 0113 suggests a significant increase in the stiffness of the pavement-subgrade after the first deflection basin measurements were made.

Figure WS-14(b) shows the deflection measured by sensor #7 of the FWD. As shown, no

significant change in deflection values for sensor #7 were recorded within sections 0113 and 0116.

Figure WS-14(c) shows the difference in the deflections measured by sensors #1 and #3.

As shown, there is more than a 50 percent reduction in the deflection difference for section 0113 between the first and second dates when deflections were measured; while no significant reduction was found or measured within section 0116.

-0.600

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

0 10 20 30 40 50 60 70 80

Offset from Lane Centerline

Dif

fere

nti

al L

ayer

Th

ickn

ess,

Ru

ttin

g,

in.

Surface Binder Layer ATB Layer



J - 165

Figure WS-14. Deflections Measured Over Time for the Two Wisconsin SPS-1 Sections that Were Trenched (55-0113 and 55-0116)

In summary, the deflection basin data measured over time suggest a significant increase in overall pavement stiffness for section 0113 between the first and second dates when deflections were measured after construction; while no increase in pavement stiffness was found within section 0116. The deflection basin data also suggest that this increase in stiffness was not caused by the embankment or subgrade soils. The other comparison of the deflection values was between the SPS-1 and SPS-9 sections with comparable layer thickness. All of these sections have a crushed stone base and no ATB layer (refer to table WS-1). Figure WS-15 shows the same comparisons between different deflection values that were used in figure WS-14. As shown, the embankment or subgrade is weaker, but there is no significant reduction in deflection values or increase in stiffness for these sections. Thus, it is expected that section 0113 maybe the only SPS-1 section that exhibited this increase in stiffness shortly after construction. This discrepancy in thickness and changes in the crushed stone aggregate base properties over time (those sections without ATB, as well as with the ATB layer) were not resolved or explained other than the crushed stone base was stabilized.

0100200300400500600700800

11-Mar-97

24-Jul-98

06-Dec-99

19-Apr-01

01-Sep-02

14-Jan-04

28-May-05

Date of Deflection Measurement

Def

lect

ion

, Sen

sor

1, m

ils

Section 0113 Section 0116

0102030405060708090

11-Mar-97

24-Jul-98

06-Dec-99

19-Apr-01

01-Sep-02

14-Jan-04

28-May-05


Def

lect

ion

, Sen

sor

7, m

ils


0

100

200

300

400

500

11-Mar-97

24-Jul-98

06-Dec-99

19-Apr-01

01-Sep-02

14-Jan-04

28-May-05


Def

lect

ion

Dif

fere

nce

, S

enso

r 1

- S

enso

r 3,

mils


(a) Deflections Measured by Sensor #1, Indicative of Overall Pavement-Subgrade

Stiffness and Changes in Stiffness with Time.

(b) Deflections Measured by Sensor #7, Indicative of Subgrade Stiffness and Changes

in Subgrade Stiffness with Time.

(c) Deflections Differences, Sensor #1 Minus Sensor #3, Indicative of Overall Pavement Stiffness and

Changes in Pavement Stiffness with Time.



J - 166

Figure WS-15. Deflections Measured Over Time Comparing Wisconsin SPS-1 Section 0114

and Two SPS-9 Sections (C901 and C960) J-9.7 HMA Mixture Characterization Tests for Rutting Predictions Dynamic modulus and repeated load permanent deformation tests were performed on test specimens reconstituted and compacted to the average in place properties of the HMA wearing surface, binder layer, and ATB mixtures reported in the LTPP database. Figure WS-16 presents the dynamic modulus values measured on the HMA mixtures, which were entered in the MEPDG for predicting rut depth over time using the global and field-derived plastic deformation coefficients. The ATB mixture exhibited lower dynamic moduli at the higher test temperatures, while the HMA wearing surface exhibited the higher dynamic moduli. The dynamic modulus test results are summarized in Appendix D, while the results from the repeated load permanent deformation tests are included in the final report and in Appendix E.

0

100

200

300

400

500

600

700

800

11-Mar-97

24-Jul-98

06-Dec-99

19-Apr-01

01-Sep-02

14-Jan-04

28-May-05


De

fle

cti

on

, Se

ns

or

#1

, mils

Section 0114 Section C901 Section C960

0

10

20

30

40

50

60

70

80

90

11-Mar-97

24-Jul-98

06-Dec-99

19-Apr-01

01-Sep-02

14-Jan-04

28-May-05


De

fle

cti

on

, Se

ns

or

#7

, mils


050

100150200250300350400450500

11-Mar-97

24-Jul-98

06-Dec-99

19-Apr-01

01-Sep-02

14-Jan-04

28-May-05


De

fle

cti

on

Dif

fere

nc

e, S

en

so

r 1

-S

en

so

r 3

, mils


(a) Deflections Measured by Sensor #1, Indicative of Overall Pavement-Subgrade

Stiffness and Changes in Stiffness with Time.

(b) Deflections Measured by Sensor #7, Indicative of Subgrade Stiffness and Changes

in Subgrade Stiffness with Time.

(c) Deflections Differences, Sensor #1 Minus Sensor #3, Indicative of Overall Pavement Stiffness and

Changes in Pavement Stiffness Over Time.



J - 167

Figure WS-16. Dynamic Modulus Values Measured on the Mixtures for the Different HMA

Layers for the Wisconsin SPS-1 Project

(a) Wearing Surface.

(b) Binder Layer.

(c) ATB Layer.



J - 168

J-9.8 Rut Depths Predicted Using the Global Transfer Function Coefficients The MEPDG was used to predict the rut depths for each section using the global calibration parameters. Figure WS-17 compares the measured and predicted rut depths using the global calibration values for the MEPDG vertical strain transfer function. As shown, there are two distinct groups of data: one for those test sections that include an asphalt treated base layer and those that do not. It is expected that the majority of the rutting has occurred in the ATB layer, which was confirmed with the trench. The test sections with the ATB layer are also those with the thicker combined HMA layers, as shown in figure WS-2.

Figure WS-17. Comparison of Measured and Predicted Rut Depths Using the Global

Calibration Values for the MEPDG Rut Depth Transfer Function Figure WS-18 show the effect of the ATB on the total rut depths measured along selected SPS-1 test sections. As shown, the higher rut depths were measured on all test sections with ATB layers. In summary, most of the rutting occurred in the ATB layer. The HMA binder layer, however, did exhibit some rutting. Figure WS-19 provides a comparison of the measured versus predicted rut depth for the Wisconsin SPS-9 test sections with PMA mixtures. As shown, the MEPDG consistently over predicts the rutting of the PMA mixtures. This observation was also made in an Asphalt Institute study comparing PMA to neat HMA mixtures using the MEPDG. Figure WS-20(a) shows a comparison of the measured and predicted rut depths. A comparison of the residual errors and predicted rut depths is shown in figure WS-20(b). As shown, there is significant deviation between the measured and predicted rut depths and the residual error is dependent on the predicted rut depth. More importantly, the residual error is dependent on the type of mixture (ATB versus HMA) and type of binder (SPS-1 versus SPS-9 sections). Layer thickness is another parameter that is taken into account in the rut depth prediction procedure, which is explained in the following paragraphs.

0.000.050.100.150.200.250.300.350.400.45

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45


Pre

dic

ted

Ru

t D

epth

, in

.

SPS-9 Sections SPS-1, DGAB SPS-1, PATB/DGAB

SPS-1,ATB SPS-1, ATB/PATB Line of Equality



J - 169

Figure WS-18 Comparison of the Measured Rut Depths over Time for the Wisconsin SPS-1

Test Sections with and without an ATB Layer

0.000

0.100

0.200

0.300

0.400

0.500

0.00 2.00 4.00 6.00 8.00 10.00

Age, years

Ru

t D

epth

, in

.

Measured Values Predicted Values

0.000

0.100

0.200

0.300

0.400

0.500

0.00 2.00 4.00 6.00 8.00 10.00

Age, years

Ru

t D

epth

, in

.


Section 55-0113; No ATB Layer Section 55-0115; ATB Layer

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.00 2.00 4.00 6.00 8.00 10.00

Age, years

Ru

t D

epth

, in

.


0.000

0.100

0.200

0.300

0.400

0.500

0.00 2.00 4.00 6.00 8.00 10.00

Age, yearsR

ut

Dep

th,

in.


Section 55-0114; No ATB Layer Section 55-0116; ATB Layer



J - 170

Figure WS-19 Comparison of Predicted and Measured Rut Depths for the Wisconsin SPS-9

Test Sections

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.000 2.000 4.000 6.000 8.000 10.000

Age, years

Ru

t D

epth

, in

.


0.0000.0500.1000.1500.2000.2500.3000.3500.400

0.000 2.000 4.000 6.000 8.000 10.000

Age, years

Ru

t D

epth

, in

.


0.0000.0500.1000.1500.2000.2500.3000.3500.400

0.000 2.000 4.000 6.000 8.000 10.000

Age, years

Ru

t D

epth

, in

.


Test Section 55-C901





J - 171

Figure WS-20. Comparison of the Predicted and Measured Rut Depths and Residual Error

Using the MEPDG Global Calibration Values for the SPS-1 and SPS-9 Projects. The rut depth predictions using the MEPDG Global transfer function using the vertical plastic strain were modified based on adjusting the kr1 parameter with layer thickness corrections or adjustments. The rut depth predictions made with the thickness corrections resulted in a significant improvement in reducing the bias, but there is a confounding factor or interrelationship between the different mixtures (ATB versus the HMA binder layers) and layer thickness. This confounding factor was explained earlier in the test section report and can lead to misleading results and application of an incorrect adjustment to reduce the bias without reducing the standard error. The NCHRP Project 1-40B mixture adjustment parameters were used to estimate the permanent deformation constants for the different mixtures and layers of the Wisconsin SPS-1 and SPS-9 projects. The values estimated for each layer are included at the end of this test section report.

00.050.1

0.150.2

0.250.3

0.350.4

0.45

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45

Measured Rut Depths, in.

Pre

dic

ted

Ru

t D

epth

s U

sin

g

Glo

bal

Cal

ibra

tio

n

Par

amet

ers,

in

.

SPS-9 Sections without ATB Layer SPS-1 Sections with ATB Layer

SPS-1 Sections without ATB Layer Line of Equality

-0.400-0.300-0.200-0.1000.0000.1000.2000.3000.400

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

Predicted Rut Depths, in.

Res

idu

al E

rro

r (P

red

icte

d

Min

us

Mea

sure

d V

alu

es),

in

.

SPS-9 Sections without ATB SPS-1 Sections without ATB Layers

SPS-1 Sections with ATB

(b) Predicted versus residual errors.

(a) Measured versus predicted rut depths.



J - 172

The equivalent permanent deformation constants were determined for the entire HMA thickness using the equivalent thickness method suggested in NCHRP Project 1-40B. The HMA mixture designs were requested from the Wisconsin DOT, but were unavailable for determining the NCHRP Project 1-40B mixture adjustment factors. Other mixture designs of similar materials were used to estimate the mixture adjustment factors for the SPS-1 and SPS-9 projects. The mixture adjustment factors, however, need to represent the in place mixture volumetric properties at construction. Thus, the average HMA volumetric and aggregate properties were extracted from the LTPP database. The average gradation was prepared for estimating the rut depth mixture adjustment factors in accordance with the procedure identified in NCHRP Project 1-40B (see Figure WS-21). Figure WS-22 compares the predicted and measured rut depths using the mixture adjustment factors, as well as comparing the predicted rut depths to the residual errors. As shown, most of the bias has been removed and the standard error has been significantly reduced in comparison to the use of the global MEPDG transfer function coefficients; BUT—there is still a significant standard error between the measured and predicted values. Another important observation is that the rut depth was consistently over predicted for those sections with PMA mixtures, which was not the case for those sections without PMA mixtures (the SPS-1 sections). Figure WS-23 shows a similar trend between the predicted and measured rut depths when using the Modified Leahy transfer function in comparison to the use of the MEPDG rut depth transfer function. Figures WS-24 and WS-25 show the same comparison between the predicted and measured rut depths for the other transfer functions included in the MEPDG NCHRP 9-30A software version—Verstraeten deviator stress transfer function and WesTrack shear strain and stress transfer function. As shown, the data for the Verstraeten and WesTrack transfer functions have similar trends which are different in comparison to the MEPDG vertical strain transfer function (refer to figure WS-17). Figure WS-26 compares the predicted average and measured rut depths made at different times for section 0113. An important observation from this comparison is the change in rut depths measured over time relative to the predicted values for the different transfer functions. In addition, all of the rut depth transfer functions over predict the measured rutting depths and the rut depth growth rate for the predicted values is higher than for the measured rut depths time-series data.



J - 173

Figure WS-21 Gradations for the Wisconsin SPS-1 Wearing Surface and Binder Layer.



J - 174


Using the NCHRP 1-40B Mix Adjustment Values for the SPS-1 and SPS-9 Sections

00.050.1

0.150.2

0.250.3

0.350.4

0.45

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45

Measured Rut Depths, in.

Pre

dic

ted

Ru

t D

epth

s U

sin

g M

ix A

dju

stm

ent

Par

amet

ers,

in

.

SPS-9 Sections without ATB Layer SPS-1 Sections with ATB Layer

SPS-1 Sections without ATB Layer Line of Equality

-0.400-0.300-0.200-0.1000.0000.1000.2000.3000.400

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Predicted Rut Depth with Mixture Adjustment Factors, in.

Res

idu

al E

rro

r (P

red

icte

d M

inu

s M

easu

red

Val

ues

), i

n.

SPS-9 Sections without ATB SPS-1 Sections without ATB

SPS-1 Sections with ATB



J - 175

Figure WS-23. Comparison of the Predicted and Measured Rut Depths Using the Global Calibration Values for the Modified Leahy Transfer Function for the SPS-1 and SPS-9

Projects.

Figure WS-24. Comparison of the Predicted and Measured Rut Depths and Residual Error Using the Global Values for the Verstraeten Deviator Stress Transfer Function for the SPS-

1 and SPS-9 Sections

y = 1.1512x

R2 = ‐0.2054

0

0.1

0.2

0.3

0.4

0.5

0.6

0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350 0.400 0.450Measured Rutting, in

Predicted Rutting, in

y = 0.7834x

R2 = ‐0.9746

0

0.1

0.2

0.3

0.4

0.5

0.6

0.000 0.100 0.200 0.300 0.400 0.500

Measured Total Rutting, in

Predicted Total R

utting, in



J - 176


Using the Global Values for the WesTrack Shear Strain and Stress Transfer Function for the SPS-1 and SPS-9 Sections

Figure WS-26. Comparison of the Predicted and Measured Rut Depths Made at Different

Times for Section 0113 Using the Global Constants of the Different Transfer Functions

y = 0 .7 6 0 1 x

R 2 = ‐1 .2 9 0 5

0

0 .0 5

0 .1

0 .1 5

0 .2

0 .2 5

0 .3

0 .3 5

0 .4

0 .4 5

0 .0 0 0 0 .1 0 0 0 .2 0 0 0 .3 0 0 0 .4 0 0 0 .5 0 0

M easu re d To ta l Ru ttin g , in

Predicted Total R

utting, in

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0 1 2 3 4 5 6 7 8 9

Age, years

Ru

t D

epth

, in

.

Measured Values; 55-0113

MEPDG, Global

MEPDG, Mix Adjust.

Verstraetan

WesTrack



J - 177

J-9.9 Field-Derived Plastic Deformation Coefficients This section summarizes the comparison of the predicted and measured rut depths using laboratory permanent deformation test results in support of the different rut depth transfer functions. Table WS-2 summarizes the field-derived coefficients of each transfer function and test section, while Figures WS-27 and WS-28 compare the predicted and measured rut depth for the test sections with and without an ATB layer, respectively. As shown, each transfer function accurately predicted the measured rut depths. The other important observation is that the exponent to the number of load cycle term is the same between all transfer functions for an individual test section.

Table WS-2. Field-Derived Slope and Intercept


1-40B Modified


Slope Without ATB 0.33 0.33 0.33 0.33 0.33

With ATB 0.38 0.38 0.38 0.38 0.38

Intercept

0113 -2.78 -2.40 -0.96 110 1.12 0114 -2.27 -2.40 -1.10 95 1.0 0116 -1.87 -2.58 -1.53 85 0.85 0117 -1.90 -2.58 -1.25 90 0.75



J - 178

Figure WS-27. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0113 and 0114; without an

ATB Layer



J - 179

Figure WS-28. Predicted versus Measured Rut Depths using MEPDG Version 9-30A and the Field-Derived Plastic Deformation Coefficients for Sections 0116 and 0117; with ATB

Layer



J - 180



Surface Binder ATB PATB

Bulk Specific Gravity Gmb 2.284 2.308 2.321 2.23

Maximum Specific Gravity Gmm 2.443 2.443 2.467 2.59

Air Voids, % Va 6.51 5.53 5.92 13.90

Air Voids for Target Asphalt Content, % Va(design) 4.00 4.00 4.00 15.00

Total Asphalt Content by Weight, % Pb 6.20 5.80 4.40 2.00


Aggregate Effective Specific Gravity Gse 2.672 2.655 2.627 #DIV/0!

Bulk Specific Gravity of Aggregate Blend Gsb 2.623 2.606 2.579 #DIV/0!

Effective Asphalt Content by Volume, % Vbe 11.810 11.059 8.042 #DIV/0!

Voids in Mineral Aggregate, % VMA 18.3 16.6 14.0 #DIV/0!Voids Filled with Asphalt, % VFA 64.5 66.7 57.6 #DIV/0!




Log Kr1 2.43 2.43 2.38

Rut Depth Coefficient kr1 -2.338 -2.403 -2.577 #DIV/0!

Temperature Exponent kr2 1.586 1.523 1.807 #DIV/0!

Traffic Loadings Exponent kr3 0.335 0.335 0.383 #DIV/0!


Kr1 Value 269.15348 269.15348 239.88329 1Absorbed Asphalt by Weight, % Pba 0.75 0.75 0.75kr1 Log Value 12.918149 11.103557 7.4442164 #DIV/0!


Wisconsin SPS-1 & SPS-9 Projects



J - 181

J-9.11 Average Rut Depth Measurements Extracted from LTPP Database for the Wisconsin SPS-1 and SPS-9 Projects

SPS -1 TEST SECTION

Section Date Age, years Rut Depth, in.55_0113 23-Apr-98 0.56 0.05955_0113 13-Aug-99 1.87 0.17755_0113 12-Jun-00 2.7 0.15755_0113 03-Sep-00 2.93 0.15755_0113 19-Sep-01 3.97 0.20755_0113 25-Apr-02 4.57 0.15755_0113 23-Jun-02 4.73 0.17755_0113 27-Jul-03 5.82 0.13855_0113 21-Jul-04 6.81 0.22655_0113 11-Aug-05 7.87 0.226

55_0114 22-Apr-98 0.56 0.03955_0114 13-Aug-99 1.87 0.19755_0114 08-Jun-00 2.69 0.14855_0114 03-Sep-00 2.93 0.15755_0114 19-Sep-01 3.97 0.23655_0114 22-Apr-02 4.56 0.19755_0114 23-Jun-02 4.73 0.19755_0114 27-Jul-03 5.82 0.15755_0114 20-Jul-04 6.81 0.23655_0114 09-Aug-05 7.86 0.266

55_0119 13-Aug-99 1.87 0.21755_0119 12-Jun-00 2.7 0.19755_0119 03-Sep-00 2.93 0.15755_0119 19-Sep-01 3.97 0.21755_0119 23-Apr-02 4.56 0.21755_0119 23-Jun-02 4.73 0.17755_0119 27-Jul-03 5.82 0.19755_0119 21-Jul-04 6.81 0.25655_0119 09-Aug-05 7.86 0.276



SPS-1 Sections









J - 182

SPS-9 TEST SECTIONS



Section Date Age, years Rut Depth, in.C901 22-Apr-98 1.751 0.028C901 08-Jun-00 3.882 0.148C901 03-Sep-00 4.121 0.148C901 22-Apr-02 5.753 0.155C901 23-Jun-02 5.923 0.141C901 28-Sep-03 7.189 0.169C901 23-Jul-04 8.008 0.191

C902 22-Apr-98 1.751 0.042C902 08-Jun-00 3.882 0.148C902 03-Sep-00 4.121 0.134

C902 22-Apr-02 5.753 0.162C902 23-Jun-02 5.923 0.162C902 28-Sep-03 7.189 0.141C902 22-Jul-04 8.005 0.191

C903 22-Apr-98 1.751 0.028C903 08-Jun-00 3.882 0.092C903 03-Sep-00 4.121 0.099C903 22-Apr-02 5.753 0.120C903 23-Jun-02 5.923 0.113C903 28-Sep-03 7.189 0.099C903 22-Jul-04 8.005 0.099

SPS-9 Section


C959 22-Apr-98 1.751 0.035C959 08-Jun-00 3.882 0.120C959 03-Sep-00 4.121 0.120C959 23-Jun-02 5.923 0.106C959 28-Sep-03 7.189 0.127C959 23-Jul-04 8.008 0.155

C960 22-Apr-98 1.751 0.028

C960 08-Jun-00 3.882 0.085C960 03-Sep-00 4.121 0.113C960 23-Jun-02 5.923 0.127C960 28-Sep-03 7.189 0.071C960 22-Jul-04 8.005 0.113



J - 183

J-9.12 MEPDG Input Summary: Wisconsin SPS-5 Test Section Example The following is a summary of the inputs that were used for the MEDPG runs using the NCHRP 9-30A version of the MEDPG. These are provided as an example to document the data and information included for this SPS-5 project.

Limit Reliability

57.9 172 90 2000 90 25 90 1000 90 25 90 0.75 90 0.25 90

520 1 100 100 60

Project: 55_0113 Verst

General Information Description:

Design Life 25 yearsBase/Subgrade construction: September, 1997Pavement construction: October, 1997Traffic open: November, 1997Type of design Flexible

Analysis Parameters

Performance CriteriaInitial IRI (in/mi)Terminal IRI (in/mi)AC Surface Down Cracking (Long. Cracking) (ft/mile):AC Bottom Up Cracking (Alligator Cracking) (%):AC Thermal Fracture (Transverse Cracking) (ft/mi):Chemically Stabilized Layer (Fatigue Fracture)Permanent Deformation (AC Only) (in):Permanent Deformation (Total Pavement) (in):

Location: MARATHONProject ID: 55_0113Section ID: SR-29 Date: 11/10/2006 Station/milepost format: Miles: 0.000Station/milepost begin: Station/milepost end: Traffic direction: West





J - 184



J - 185

44.87 -89.29 1239 10

LoadTime(sec)

LowTemp.

-4ºF(1/psi)

Mid.Temp.14ºF

(1/psi)

HighTemp.32ºF


Climate icm file:

D:\users\Aliex\55_0100.icm Latitude (degrees.minutes)Longitude (degrees.minutes)Elevation (ft)Depth of water table (ft)


HMA E* Predictive Model: NCHRP 1-37A viscosity based model.HMA Rutting Model coefficients: NCHRP 1-37A coefficientsEndurance Limit (microstrain): None (0 microstrain)







Asphalt MixCumulative % Retained 3/4 inch sieve: 1Cumulative % Retained 3/8 inch sieve: 13.833Cumulative % Retained #4 sieve: 33.667% Passing #200 sieve: 3.5167



Layer 2 -- Asphalt concreteMaterial type: Asphalt concreteLayer thickness (in): 3.6





Asphalt MixCumulative % Retained 3/4 inch sieve: 1Cumulative % Retained 3/8 inch sieve: 13.833Cumulative % Retained #4 sieve: 33.667% Passing #200 sieve: 3.5167




J - 186

Value 4.2454 1.5942 0.76207 120.2

Layer 3 -- A-1-aUnbound Material: A-1-aThickness(in): 8




#200 10.1#100 #80 14.66666667#60 #50 #40 #30 #20 #16 #10 50#8 #4 62.66666667

3/8" 75.333333331/2" 82.333333333/4" 96.333333331" 100

1 1/2" 1002" 100

2 1/2" 3" 100

3 1/2" 4"



Parametersabc

Hr.

Value 5.9882 0.66702 1.4669 124.7

Layer 4 -- A-1-bUnbound Material: A-1-bThickness(in): 24


ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 1Liquid Limit (LL) 13Compacted Layer NoPassing #200 sieve (%): 12.4Passing #40 35.7Passing #4 sieve (%): 76D10(mm) 0.02128D20(mm) 0.1832D30(mm) 0.3227D60(mm) 1.362D90(mm) 15.96


#200 12.35#100 #80 21.25#60 #50 #40 #30 #20 #16 #10 68#8 #4 76

3/8" 831/2" 86.53/4" 92.51" 95

1 1/2" 972" 98.5

2 1/2" 3" 100

3 1/2" 4"



Parametersabc

Hr.



J - 187

Value 4.9943 1.1063 0.89245 122

Layer 5 -- A-1-bUnbound Material: A-1-bThickness(in): Semi-infinite


ICM InputsGradation and Plasticity IndexPlasticity Index, PI: 1Liquid Limit (LL) 13Compacted Layer NoPassing #200 sieve (%): 11Passing #40 34.3Passing #4 sieve (%): 75D10(mm) 0.04109D20(mm) 0.212D30(mm) 0.3453D60(mm) 1.492D90(mm) 13.72


#200 11#100 #80 20#60 #50 #40 #30 #20 #16 #10 66#8 #4 75

3/8" 841/2" 883/4" 971" 100

1 1/2" 1002" 100

2 1/2" 3" 100

3 1/2" 4"



Parametersabc

Hr.



J - 188

0.007566 3.9492 1.281

-3.35412 1.5606 0.4791

1.5

1 1

2.03 1.35

7 3.5 0 1000 1 1 0 6000

1 1 0 1000

40 0.4 0.008 0.015 40.8 0.575 0.0014 0.00825



k1k2k3


k1k2k3


0.24*POWER(RUT,0.8026)+0.001


k1



k1k2


Granular:k1

Fine-grain:k1








IRI

C1(HMA/PCC)C2(HMA/PCC)C3(HMA/PCC)C4(HMA/PCC)

IRI HMA Pavements NewC1(HMA)C2(HMA)C3(HMA)C4(HMA)

IRI HMA/PCC Pavements

Documents

NCHRP 9-30A CALIBRATION OF RUTTING MODELS …onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP09-30A_NR...NCHRP 9-30A September 2010 Appendix J Evaluation of Test Sections Used for Calibration