Impact of Superpave Mix Design Method on Rutting Behaviour ...prr.hec.gov.pk/jspui/bitstream/123456789/1213/1/765S.pdf · I certify that research work titled “Impact of Superpave

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Impact of Superpave Mix Design Method on Rutting Behaviour of Flexible Pavements

Author

Kamran Muzaffar Khan 04-UET/PhD-CIVIL-08

Supervisor

Dr. Mumtaz Ahmed Kamal Professor, Department of Civil Engineering

DEPARTMENT OF CIVIL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING

UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA

August 2008

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Impact of Superpave Mix Design Method on Rutting Behaviour of Flexible Pavements

A dissertation submitted in partial fulfilment of the requirements for the degree of Doctor of

Philosophy (PhD) in Civil Engineering (Specialization in Transportation Engineering)

Author Engr. Kamran Muzaffar Khan

(04-UET/PhD-CIVIL-08) Checked and Recommended by the Foreign Experts: Dr. David Hughes Senior Lecturer, The Queen’s University of Belfast N.Ireland, UK.

Prof. Dr. Ali Porbaha Civil Engineering Department, California State University Sacramanto, CA, USA.

Approved by:

Prof. Dr. M. A. Kamal Supervisor/Internal Examiner

Prof. Dr. Muhammad Wasim Mirza External Examiner Department, of Transportation Engineering & Management Sciences, UET, Lahore

Prof. Dr. Mir Shabbar Ali External Examiner Chairman, Department of Urban and Infrastructure Engineering, NED, UET, Karachi

DEPARTMENT OF CIVIL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING

UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA

AUGUST 2008

iii

ABSTRACT

Effective communication is a key to national progress. Pakistan is located in a region

where South-Asia converges with Central Asia and the Middle East. Blessed with

extensive natural resources and rich agricultural land, it improves its economy

particularly by exporting valuable items. In order to improve trade and economic

activities and to materialize regional linkages with China, Afghanistan, Iran, Russia and

other neighbouring Central Asian countries, the country is gearing up towards a large

infrastructure network. Roads constitute a vital part of the infrastructure. In Pakistan most

of the roads are constructed using flexible pavement concept, due to their comparatively

low construction and maintenance cost.

Pakistan has national highways with a length over 9555 Kilometers and motorways of

515 Kilometers. The drastic increase in traffic volume during the last few decades has

resulted in premature pavement failures of almost the whole infrastructure of Pakistan.

Premature rutting of flexible pavements is one of the major pavement distresses being

faced by the country which is primarily due to uncontrolled axle load and high ambient

temperatures. Rutting in asphaltic concrete depends on many factors, such as the

composition of asphalt mixes, grading and quality of aggregates, type of binder,

percentage of the bituminous binder, air void contents, degree of compaction,

environmental conditions, load repetition, the substructure, and the bearing capacity of

the subgrade.

The objective of this research work was to compare the Superpave, Stone Mastic Asphalt

(SMA) and Marshall methods of mix design of asphaltic concrete and to propose rut

resisting asphalt mix suitable for local loading and environmental conditions. The mixes

selected for the study were dense graded in case of Superpave and Marshall methods

whereas gap graded for SMA. A comprehensive testing program was conducted on the

samples prepared in the laboratory at the design asphalt contents and aggregate

gradations.

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Physical properties of aggregates and asphalt were determined in the laboratory

confirming to ASTM and AASHTO specifications. Mechanical Properties of Marshall,

Superpave and Stone Mastic Asphalt (SMA) were evaluated by performing Indirect

Tensile Modulus Test, Uniaxial Loading Strain Test (Creep Test), Dynamic Modulus

Test and Wheel Tracking Test under prevailing load and environmental conditions of

Pakistan in order to compare the performance of mixes.

The study revealed that Superpave mixes performed better than Marshall and SMA mixes

in terms of low induced permanent strains, high modulus of resilience, high dynamic

modulus and better resistance against wheel rutting during wheel tracking test. Superpave

technology can be adopted for the design of Hot Mix Asphalt (HMA) pavements in the

country due to its superiority over the conventional mix design procedures. The

guidelines for implementing Superpave mix design procedure in Pakistan have been

proposed.

In addition, a performance grading map has been proposed to be implemented in Pakistan

by dividing it into seven zones according to the highest and lowest pavement

temperatures.

Keywords: Superpave, Rutting, Hot Mix Asphalt, Pavement

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UNDERTAKING

I certify that research work titled “Impact of Superpave Mix Design Method on Rutting Behaviour of Flexible Pavements” is my own work. The work has not been presented elsewhere for assessment. Where material has been used from other sources it has been properly acknowledged / referred.

Kamran Muzaffar Khan

04-UET/PhD-CE-08

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ACKNOWLEDGEMENTS

I would like to express deep gratitude to my creator The Allah for giving me talent, skill opportunity, perseverance and power to reach this milestone in my career. I would also like to pay my regards to Prophet Muhammad (P.B.U.H) whose ideal life guided me through difficult and tough situations. Prof. Dr. M. A. Kamal, my thesis supervisor for his incessant support and exceptional guidance throughout my research work. His efforts in promoting the research culture in the field of Transportation Engineering in Pakistan resulted in the establishment of Taxila Institute of Transportation Engineering (TITE). State of the art testing equipments of International Standards helped me a lot to carry out my testing work. Dr. Zia Zafir, California, U.S.A and Prof. Dr. Muhammad Waseem Mirza, UET Lahore, helped me a lot in selection of my research topic and testing matrix. Engr. Asim Amin, GM (Design) and Dr. Shahab Khanzada, (Pavement Specialist), NHA, for their technical assistance is noteworthy. Special thanks to worthy Prof. Dr. Habibullah Jamal, Vice Chancellor for his efficient management that made me feel no hindrance. Chairman, Prof. Dr. Abdul Razzaq Ghumman, for his throughout encouragement during my research work and raising my moral. He also spared me from extra academic and administrative loads which enabled me to focus my research engagements. I would like to thank all of my colleagues, especially Engr. Imran Hafeez for his assistance. Mr. Toqeer Mehmood and Mr. Shakeel Hussain were always ready to help me whenever I was in need of them. I would always remember the continuous assistance of Engr. M. Hasan Khalil in executing laboratory work and thesis compilation. The invaluable contribution of my Parents, Wife and Children in the form of prayers, encouragement and patience who suffered the most due to my research commitments are highly appreciated.

(Kamran Muzaffar Khan)

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TABLE OF CONTENTS Abstract.………………………………………………………………………..……….. iii

Undertaking.…………………………………………………………..……….……...... v

Acknowledgement………………………………..…………………………….………. vi

List of Figures…………………………………………………………….…………..… x

List of Tables.……………………………………………………………….………….. xv

Chapter I: Introduction

1.0 General………………………………………………………….…….... 2

1.1 Structural Behavior of Flexible Pavement……………………….…….. 2

1.2 Visco-Elastic Behavior of Asphalt…………………………………….. 3

1.3 Flexible Pavements Distresses in Pakistan…………………………….. 5

1.3.1 Rutting……………………………………………………….. 5

1.3.2 Fatigue……………………………………………………….. 6

1.4 Solutions to the Rutting Problems in Hot Mix Asphalt (HMA)……….. 7

1.5 Research Objectives……………………………………………………. 9

1.6 Scope of Work…………………………………………………………. 9

Chapter II: Literature Review

2.1 Permanent Deformation in Flexible Pavements……………………….. 14

2.2 Types of Rutting in Asphaltic concrete………………………………... 15

2.2.1 Rutting due to Densification……………………………….... 15

2.2.2 Rutting due to Shear Failure……………………………….... 16

2.3 Factors affecting Rutting………………………………......................... 17

2.4 Rutting Potential of Different mixes………………………………........ 21

2.5 Performance of SMA against Rutting………………………………...... 22

2.6 Standard Types of Performance Testing Methods……………………... 23

Chapter III: Superpave Mix Design Method

3.0 Introduction…………………………………………………………….. 29

3.1 Superpave Asphalt Binder Tests……………………………………….. 29

3.1.1 Dynamic Shear Rheometer (DSR)…………………………... 30

3.2 Formation of Binder Grades…………………………………………… 37

3.3 Volumetric Properties of Superpave Mixes……………………………. 39

3.3.1 Percent VMA in compacted Paving Mixture........................... 40

viii

3.3.2 Percent VFA in Compacted Mixture………………………... 41

3.3.3 Percent Air Voids in compacted Mixture…………………… 42

3.4 Performance Evaluation of Superpave Mixes…………………………. 42

3.5 Comparison of Superpave with Conventional Mixes………………….. 44

Chapter IV: Performance Grading of Asphalt

4.0 Introduction……………………………….............................................. 47

4.1 Collection of Air Temperature Data across Pakistan………………….. 48

4.2 Analysis of the Air Temperature Data…………………………………. 50

4.3 Zoning of Pakistan on the basis of Pavement Temperatures…………... 53

Chapter V: Material Characterization

5.0 Introduction……………………………….............................................. 56

5.1 Aggregates Properties……………………………….............................. 56

5.1.1 Consensus Aggregate Properties…………………………….. 56

5.1.1.1 Coarse Aggregate Angularity……………………. 57

5.1.1.2 Fine Aggregate Angularity………………………. 58

5.1.1.3 Flat and Elongated Particles……………………... 59

5.1.1.4 Clay Content (Sand Equivalent)…………………. 60

5.1.2 Source Aggregate Properties………………………………… 61

5.1.2.1 Toughness………………………………………... 61

5.1.2.2 Soundness………………………………………... 62

5.1.2.3 Deleterious Materials……………………………. 62

5.2 Aggregate Gradation…………………………………………………… 63

5.2.1 Control Points……………………………….......................... 64

5.2.2 Restricted Zone……………………………………………… 64

5.3 Binder Testing………………………………...……………………….. 68

Chapter VI: Performance Based Testing

6.0 Introduction………………………………...…………………………... 71

6.1 Indirect Tensile Modulus Test………………………………................. 72

6.2 Uniaxial Loading Strain Test (Creep Test)…………………………….. 74

6.3 Dynamic Modulus Test………………………………............................ 97

6.4 Wheel Tracking Test……………………………….............................. 110

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Chapter VII: Discussion

7.0 Introduction………………………………...…………………………. 121

7.1 Volumetric Study of Different Mixes……………………………….... 121

7.2 Performance Based Properties………………………………............... 122

7.2.1 Modulus of Resilience………………………………............ 122

7.2.2 Repeated Uniaxial Loading Strain Test Properties………… 122

7.2.2.1 Accumulated Strain…………………………... 123

7.2.2.2 Creep Stiffness………………………………... 124

7.2.2.3 Resilient Strain……………………………….. 124

7.2.2.4 Resilient Modulus…………………………….. 125

7.2.3 Dynamic Modulus……………………………….................. 125

7.2.3.1 Permanent Strains…………………………….. 126

7.2.4 Rut Depth………………………………............................... 127

7.3 Master Curves Development……………………………….................. 127

Chapter VIII: Conclusions, Recommendations and Research Potential

8.1 Conclusions………………………………...…………………………. 131

8.2 Recommendations……………………………….................................. 134

References ………………………………...………………………………................ 136

Abbreviations ………………………………...………………………………............ 145

Annexure A ………………………………...………………………………............... 147

Annexure B ………………………………...………………………………............... 177

Annexure C ………………………………...………………………………............... 185

Annexure D ………………………………...………………………………............... 190

List of Publications ………………………………...………………………………... 194

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LIST OF FIGURES Number Page

Fig 1.1 Typical Asphalt Pavement Showing Stress and Strain…………………………3

Fig 1.2 Temperature Shift Behaviour of Asphalt Binder………………………………3

Fig 1.3 Microscopic Views of Liquid Flow Properties…………………………………4

Fig 1.4 Visco Elastic Behavior of Asphalt……………………………………………..5

Fig 1.5 Rutting in Outer Lane (Kashmir Highway) ……………………………………6

Fig 1.6 Severe Rutting due to Shear Failure (Islamabad Highway) ……………………6

Fig 1.7 Fatigue Cracking at (M-9 North Bound) ………………………………………7

Fig 1.8 Fatigue Cracking at (M-2 North Bound) ………………………………………7

Fig 1.9 Flow Chart Diagram (Scope of Work)……………………………….……….10

Fig 2.1 Rutting due to Densification…………………………….……….……………16

Fig 2.2 Rutting due to Shear Failure……………………………….………………… 17

Fig 3.1 Superpave Laboratory Tests with Relation to Performance……………….….30

Fig 3.2 Dynamic Shear Rheometer Operations………………………………………. 31

Fig 3.3 Viscoelastic Behavior of Binder………………………………………………32

Fig 3.4 DSR Moulds, Specimens, Plates and Spindles………………………………. 33

Fig 3.5 Asphalt Sample Configurations in DSR………………………………………34

Fig 3.6 Dynamic Shear Rheometer……………………………………………………35

Fig 3.7 Stress-Strain Output………………………………………………………….. 35

Fig 3.8 Stress- Strain Response of a Visco elsatic Material……………………………36

Fig 3.9 Asphalt Specimen Calculations……………………………………………….37

Fig 3.10 Component Diagram of Compacted HMA Specimen…………………………39

Fig 4.1 Location Map of Different Weather Stations………………………….……...50

Fig 4.2 Zoning Map…………………………………………………………………... 54

Fig 5.1 Fine Aggregate Angularity Apparatus……………….……….……………… 58

Fig 5.2 Measuring Flat and Elongated particles…………….………….….…………. 59

Fig 5.3 Sand Equivalent Test Apparatus…………………….………….…….……… 60

Fig 5.4 Superpave Gradation Limits……..………………….………….………….….64

Fig 5.5 Design Aggregate Gradations for three Mixes………………………………..67

Fig 6.1 Comparison of Resilient Modulus between Marshall, Superpave

and SMA at Different Temperatures…………………………………………

73

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Fig 6.2 Creep Testing using UTM-5P........................................................................... 74

Fig 6.3 Relationship between Resilient Strain and Stress at 25°C for 3 mixes……….77



Fig 6.6 Relationship between Resilient Strain and Temperature at 100 KPa

for 3 mixes……………………………………………………………………

78


for 3 mixes.……………………………………………………………………

79


for 3 mixes……………………………………………………………………

79

Fig 6.9 Relationship between Accumulated Strain and Pulse Count at

100 KPa and 25°C…………………………………………………………….

81


100 KPa and 40°C…………………………………………………………….

81


100 KPa and 55°C…………………………………………………………….

82


300 KPa and 25°C…………………………………………………………….

82


300 KPa and 40°C…………………………………………………………….

83


300 KPa and 55°C…………………………………………………………….

83


500 KPa and 25°C…………………………………………………………….

84


500 KPa and 40°C......................................................................................

84


500 KPa and 55°C…………………………………………………………….

85

Fig 6.18 Relationship between Accumulated Strain and Stress Level at 25°C.............. 85

Fig 6.19 Relationship between Accumulated Strain and Stress Level at 40°C.............. 86

Fig 6.20 Relationship between Accumulated Strain and Stress Level at 55°C……….. 86

Fig 6.21 Relationship between Accumulated Strain and Temperature at 100 kPa…… 87

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Fig 6.24 Relationship between Resilient Modulus and Stress Level at 25°C………… 90

Fig 6.25 Relationship between Resilient Modulus and Stress Level at 40°C................ 90

Fig 6.26 Relationship between Resilient Modulus and Stress Level at 55°C................ 91

Fig 6.27 Relationship between Resilient Modulus and Temperature at 100 kPa……... 91



Fig 6.30 Relationship between Creep Stiffness and Stress Level at 25˚C…….............. 94



Fig 6.33 Relationship between Creep Stiffness and Temperature at 100 kPa……........ 95



Fig 6.36 Extracted Sample for Dynamic Modulus Testing From 6” Dia.

Original Gyratory Sample……........……........……........……........……........

97

Fig 6.37 Dynamic Modulus Testing Arrangement using NU-14……….….…..…..…. 98

Fig 6.38 Relationship between Resilient Strain and Stress at 25°C for 3 mixes……... 100

Fig 6.39 Relationship between Dynamic Modulus and No. of Cycles for

Marshall, SMA, Superpave Mix at 500 kPa and 25°C……........……...........

100



101



101



102



102


Marshall, SMA, Superpave Mix at 35 kPa and 55°C……........…….............

103



103

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Marshall, SMA, Superpave Mix at 65 Kpa and 55°C……........……............

104

Fig 6.47 Relationship between Permanent Strain and No. of Cycles for


106



106



107



107



108



108



109



109



110

Fig 6.56 Roller Compactor Viewed from End……........……...................................... 111

Fig 6.57 Loaded wheel in contact with the specimen……........……..........……......... 112

Fig 6.58 Specimen showing rutting after completion of the test……........…….......... 112

Fig 6.59 Relationship between No. of Passes and Rut Depth for SMA

Mix at different Temperatures……........……..........……........……..............

116

Fig 6.60 Relationship between No. of Passes and Rut Depth for Marshall


117

Fig 6.61 Relationship between No. of Passes and Rut Depth for Superpave


117

Fig 6.62 Comparison of SMA, Marshall and Superpave at 25°C……….....……...…. 118

Fig 6.63 Comparison of SMA, Marshall and Superpave at 40°C……...……….......... 118

Fig 6.64 Comparison of SMA, Marshall and Superpave at 55°C………..................... 119

xiv

Fig 7.1 Effect of Stress and Resulting Accumulated Strain at the end of Test…...… 126

Fig 7.2 Master Curve for Superave Mix……………………………….…..….......... 128

Fig 7.3 Master Curve for Marshall Mix……………………………………….......... 129

Fig 7.4 Master Curve for SMA Mix……………………………..………….……… 129

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LIST OF TABLES Number Page

Table 2.1 Factors Affecting Rutting of Asphalt-Concrete Mixtures…………………21

Table 2.2 Standard Types of Performance Based Testing Methods

and Equipment……………………………………………...………….....

27

Table 3.1 Superpave Binder Test Aging Condition…………..…………….……… 30

Table 3.2 Binder Selection on the basis of Traffic Speed and Traffic Level..……... 38

Table 3.3 Superpave Volumetric Mixture Design Requirements……....….….….… 41

Table 4.1 Location of Weather Stations across Pakistan….…..……………...….…. 49

Table 4.2 Air Temperature Data for Islamabad….…..……………...….…………… 52

Table 4.2a Maximum Pavement Temperature for Islamabad….…..……………...….…52

Table 4.2b Minimum Pavement Temperature for Islamabad….…..……………...….…52

Table 4.3 Summary of Zoning….…..……………...….….….…..……………...….…53

Table 5.1 Superpave Aggregate Consensus Property Requirements….…..………… 57

Table 5.2 Aggregate Consensus Properties…………….………………………………..…. 61

Table 5.3 Aggregate Source Properties….…………………………....……...…………..… 63

Table 5.4 Superpave Mixture Gradations………….…………………………..…..... 65

Table 5.5 Superpave Aggregate Gradation Control Points……..…………………… 66

Table 5.6 Boundaries of Aggregate Restricted Zone………………….....………..… 66

Table 5.7 Design Aggregate Gradations…………………………………….………. 67

Table 5.8 Mix Design Characteristics of Three Mixes……………….….....……….. 68

Table 5.9 Physical Properties of Asphalt………………………….……..…..…….... 68

Table 5.10 Summary of Performance Based Binder Properties of 60/70

Grade Bitumen…………………………………………….………..……..

69

Table 5.11 Summary of Performance Based Binder Properties of Polymer

Modified Bitumen (1.6% Elvaloy 4160) ……………….…………….......

69

Table 6.1 Testing Conditions for Indirect Tensile Modulus Test…………….……... 72

Table 6.2 Resilient Modulus for Marshall, Superpave and SMA at

Different Temperatures………………………...………..…………………

73

Table 6.3 Uniaxial Loading Strain Test Conditions……………..…….…………..... 75

Table 6.4 Uniaxial Loading Strain Test Results Showing

Resilient Strain(%)………………………..…………………….………...

76

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Table 6.5 Uniaxial Loading Strain Test Results showing

Accumulated Strain(%)………………………………..…………..…...…

80

Table 6.6 Uniaxial Loading Strain Test Results Showing Resilient Modulus............ 89

Table 6.7 Uniaxial Loading Strain Test Results Showing Creep Stiffness…………. 93

Table 6.8 Dynamic Modulus Test Conditions Marshall, SMA and Superpave

Mix at 25°C…………………………………………..………...…………

98

Table 6.9 Comparison of Dynamic Modulus Results for Marshall, SMA

and Superpave Mix at 25°C …………………………...………..…...……

99


and Superpave Mix at 40°C…………………………………..……...……

99


and Superpave Mix at 55°C…………………………………..……...……

99

Table 6.12 Comparison of Permanent Strain Results for Marshall, SMA

and Superpave Mix at 25°C……..……………………………………….

104


and Superpave Mix at 40°C………………………………………..…….

105


and Superpave Mix at 55°C…………………..……………....……..…...

105

Table 6.15 Wheel Tracking Test Conditions…………….………..…….………..…. 111

Table 6.16 Relationship between No. of Passes and Rut Depth for SMA……......…. 113

Table 6.17 Relationship between No. of Passes and Rut Depth for Marshall…......... 113

Table 6.18 Relationship between No. of Passes and Rut Depth

for Superpave…………………………………...………...……….……..

114

Table 6.19 Comparison of Rut Depth (mm) between SMA, Marshall and

Superpave Mix at 25˚C…………………………………………..………

114

Table 6.20

Comparison of Rut Depth (mm) between SMA, Marshall and

Superpave Mix at 40˚C………………………………...…..………..……

115

Table 6.21 Comparison of Rut Depth (mm) between SMA, Marshall and

Superpave Mix at 55˚C………………………………...…..…….....……

115

Table 6.22 Summary of Wheel Tracking Test Results for Three Mixes……..….... 116

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ANNEXURE A

Table A.1 Air Temperature Data for Dalbandin…………..……………………..…..147

Table A.1a Maximum Pavement Temperature for Dalbandin………………..……... 147

Table A.1b Minimum Pavement Temperature for Dalbandin………………..……… 147

Table A.2 Air Temperature Data for Hyderabad…………..……………...…..……. 148

Table A.2a Maximum Pavement Temperature for Hyderabad ……………………... 148

Table A.2b Minimum Pavement Temperature for Hyderabad …..…………..……… 148

Table A.3 Air Temperature Data for Jacobabad……………………………………. 149

Table A.3a Maximum Pavement Temperature for Jacobabad…..…...……………… 149

Table A.3b Minimum Pavement Temperature for Jacobabad………………..……… 149

Table A.4 Air Temperature Data for Karachi……………………………….....…… 150

Table A.4a Maximum Pavement Temperature for Karachi…………....……..……... 150

Table A.4b Minimum Pavement Temperature for Karachi………………………….. 150

Table A.5 Air Temperature Data for Lassbella……………………….…..……....... 151

Table A.5a Maximum Pavement Temperature for Lassbella………………..………. 151

Table A.5b Minimum Pavement Temperature for Lasbella………………..…..……. 151

Table A.6 Air Temperature Data for Nawabshah…………………………..……..... 152

Table A.6a Maximum Pavement Temperature for Nawabshah…………........……... 152

Table A.6b Minimum Pavement Temperature for Nawabshah…...………..………... 152

Table A.7 Air Temperature Data for Nokkundi……………………..…...…………. 153

Table A.7a Maximum Pavement Temperature for Nokkundi…………..…………… 153

Table A.7b Minimum Pavement Temperature for Nokkundi……...……………....... 153

Table A.8 Air Temperature Data for Pasni…………………………………....……. 154

Table A.8a Maximum Pavement Temperature for Pasni…………..……………....... 154

Table A.8b Minimum Pavement Temperature for Pasni…………...…………..……. 154

Table A.9 Air Temperature Data for Quetta………………………………..…...….. 155

Table A.9a Maximum Pavement Temperature for Quetta…………………………... 155

Table A.9b Maximum Pavement Temperature for Quetta……………………..……. 155

Table A.10 Air Temperature Data for Rohri……………………………….…..……. 156

Table A.10a Maximum Pavement Temperature for Rohri………………..……..……. 156

Table A.10b Minimum Pavement Temperature for Rohri………………..…...………. 156

Table A.11 Air Temperature Data for Sibbi…………………………………………. 157

xviii

Table A.11a Maximum Pavement Temperature for Sibbi……………..…..………….. 157

Table A.11b Minimum Pavement Temperature for Sibbi…………..……...…………. 157

Table A.12 Air Temperature Data for Zhob…………………………………....……. 158

Table A.12a Maximum Pavement Temperature for Zhob………..……………...……. 158

Table A.12b Minimum Pavement Temperature for Zhob……...………………..……. 158

Table A.13 Air Temperature Data for Astor……………………………..………...... 159

Table A.13a Maximum Pavement Temperature for Astor…………..……..…………. 159

Table A.13b Minimum Pavement Temperature for Astor………………...……..……. 159

Table A.14 Air Temperature Data for Bahawalpur……………………….....………. 160

Table A.14a Maximum Pavement Temperature for Bahawalpur……………..……… 160

Table A.14b Minimum Pavement Temperature for Bahawalpur…………….......…… 160

Table A.15 Air Temperature Data for Balakot…………………………………...….. 161

Table A.15a Maximum Pavement Temperature for Balakot……………….....…….... 161

Table A.15b Minimum Pavement Temperature for Balakot………………….………. 161

Table A.16 Air Temperature Data for Chitral………………………….……………. 162

Table A.16a Maximum Pavement Temperature for Chitral……………….....……….. 162

Table A.16b Minimum Pavement Temperature for Chitral…………..……………….. 162

Table A.17 Air Temperature Data for Dera Ismail Khan………………....…...…….. 163

Table A.17a Maximum Pavement Temperature for Dera Ismail Khan……...…..…… 163

Table A.17b Minimum Pavement Temperature for Dera Ismail Khan……….…….… 163

Table A.18 Air Temperature Data for Dir……………………………………...……. 164

Table A.18a Maximum Pavement Temperature for Dir………………….……..……. 164

Table A.18b Minimum Pavement Temperature for Dir…………………....…………. 164

Table A.19 Air Temperature Data for Faisalabad…………………………..….……. 165

Table A.19a Maximum Pavement Temperature for Faisalabad……………..……….. 165

Table A.19b Minimum Pavement Temperature for Faisalabad………………………. 165

Table A.20 Air Temperature Data for Gilgit……………………………..…….……. 166

Table A.20a Maximum Pavement Temperature for Gilgit………………....………… 166

Table A.20b Minimum Pavement Temperature for Gilgit………………..…..…….… 166

Table A.21 Air Temperature Data for Islamabad……………………..………….….. 167

Table A.21a Maximum Pavement Temperature for Islamabad………….....…………. 167

Table A.21b Minimum Pavement Temperature for Islamabad……….…....…………. 167

xix

Table A.22 Air Temperature Data for Khanpur……………………………..……….. 168

Table A.22a Maximum Pavement Temperature for Khanpur………….…..…...…….. 168

Table A.22b Minimum Pavement Temperature for Khanpur…………….……….…... 168

Table A.23 Air Temperature Data for Kotli…………………………………....……. 169

Table A.23a Maximum Pavement Temperature for Kotli…………………...…..……. 169

Table A.23b Minimum Pavement Temperature for Kotli…………………...…..……. 169

Table A.24 Air Temperature Data for Lahore…………………………..………........ 170

Table A.24a Maximum Pavement Temperature for Lahore……………...…..………. 170

Table A.24b Minimum Pavement Temperature for Lahore…………………..………. 170

Table A.25 Air Temperature Data for Multan……………………………….………. 171

Table A.25a Maximum Pavement Temperature for Multan………...……..…………. 171

Table A.25b Minimum Pavement Temperature for Multan……………..……………. 171

Table A.26 Air Temperature Data for Murree…………………………..………........ 172

Table A.26a Maximum Pavement Temperature for Murree…………….....…………. 172

Table A.26b Minimum Pavement Temperature for Murree……………..……………. 172

Table A.27 Air Temperature Data for Muzaffarabad……………………..…………. 173

Table A.27a Maximum Pavement Temperature for Muzaffarabad………....………… 173

Table A.27b Minimum Pavement Temperature for Muzaffarabad…….....…………... 173

Table A.28 Air Temperature Data for Parachinar…………………………...………. 174

Table A.28a Maximum Pavement Temperature for Parachinaar…………....………... 174

Table A.28b Maximum Pavement Temperature for Parachinaar…………..……..…... 174

Table A.29 Air Temperature Data for Peshawar………………………..……...……. 175

Table A.29a Maximum Pavement Temperature for Peshawar………...……..……….. 175

Table A.29b Minimum Pavement Temperature for Peshawar………………..………. 175

Table A.30 Air Temperature Data for Sialkot……………………………..…...……. 176

Table A.30a Maximum Pavement Temperature for Sialkot……………………...…… 176

Table A.30b Minimum Pavement Temperature for Sialkot…………………………... 176

Table B1 Performance Based Requirements for Binder…………………………… 178

Table B2 Station wise Performance Grading …………………………………….. 180

Table C1 Performance Based Binder Properties of 60/70 Grade Bitumen………... 185

Table C2 Performance Based Binder Properties of Polymer Modified Bitumen

(1.6% Elvaloy 4160)…………………………………………………….

187

xx

Table D1 Summary Results of Uniaxial Loading Strain Test…………………....... 190

Table D2 Summary Results of Dynamic Modulus Test at 25°…………………….. 191

Table D3 Summary Results of Dynamic Modulus Test at 40°C………………….. 192

Table D4 Summary Results of Dynamic Modulus Test at 55°C………………….. 193

Chapter One

2

Chapter 1

Introduction

1.0 General

An efficient transportation system is vital for the development of any country. Pakistan has a

very important geographical and diplomatic location and has been surrounded by China (on

its far north-east), India (on its east) Afghanistan and Iran (on its west). In future, the roads of

the country will be the exit routes for gas and petroleum, worth hundreds of millions of

dollars flowing from South Asia to the entire world through Pakistan. Among other

transportation modes, highways are being used extensively for the transportation of

passengers and goods. Flexible pavements, with bituminous surfacing as wearing course are

being widely used in road construction industry due to their comparatively low construction

and maintenance costs.

1.1 Structural Behaviour of Flexible Pavement

Flexible pavement structure flexes under traffic loading and is classically composed of

numerous layers of different material types and gradations. Each layer gets the load from the

upper layer, spreads it and transfers the same to the underneath layer. Top layers being

subjected to greater load intensity, must have a high bearing capacity as compared to the

underlying layers. A typical flexible pavement structure consists of the asphalt layer at the

top with underlying unbound granular layers as shown in Figure 1.1. Horizontal tensile strain

is prominent at the bottom of asphalt layers, whereas vertical compressive stress and strain is

maximum at the top of the subgrade. The Asphalt wearing course layer is directly exposed to

the climatic variations i.e. temperature, precipitation and various types of loading

combinations and intensities. Being stiffest and contributing the most to pavement strength

and durability, wearing course is given due consideration during design and construction.

3

Figure 1.1: Typical Asphalt Pavement Showing Stress and Strain

1.2 Visco-Elastic Behavior of Asphalt

Asphalt concrete is a complex three-phase material which consists of aggregates, asphalt

binder, and air voids. Their behavior can be explained by the interaction between these three

phases and the intricate viscoelastic behavior of the binder, which depends on temperature

and loading frequency. The effects of time and temperature are inter related i.e. the behavior

of asphalt at high temperature conditions for short time spans is equivalent to its performance

at low temperature conditions for longer time durations. This concept floated by McGennis et

al. (1995) is called temperature shift or in other words the superposition theory of asphalt

binder and has been shown in Figure 1.2.

Figure 1.2 Temperature Shift Behaviour of Asphalt Binder (After McGennis et al. (1995))

4

In hot climatic conditions or under slow moving trucks, asphalt behaves like a viscous liquid

and only aggregates are the contributing element to stiffness or resistance to deformation of

hot mix asphalt that bear the traffic loads. At micro level, the contiguous layers of molecules

seem sliding past each other. This phenomenon has been presented by McGennis et al.

(1995) as shown in Figure 1.3.

Figure 1.3: Microscopic View of Liquid Flow Properties (After McGennis et al. (1995))

Whereas in cold climatic conditions or under fast moving trucks (rapidly applied loads),

asphalt behaves like an elastic solid and deforms when loaded, but returns to its original

shape when unloaded. If it is stressed beyond its strength, it may rupture.

At intermediate temperature conditions, asphalt binder exhibits the characteristics of both

viscous liquids and elastic solids. Due to this property of asphalt, it is considered to be an

excellent adhesive material for use in paving, but an extremely complicated to understand

and explain. When heated, asphalt acts as a lubricant, allowing the aggregate to be mixed,

coated, and tightly-compacted to form a smooth and dense surface. After cooling, it acts as a

glue to hold the aggregate together in a solid matrix. In its finished state, the behavior of the

asphalt is termed as visco-elastic i.e., it has both elastic and viscous characteristics, which

depends on the temperature and rate of loading as shown in Figure 1.4. Mainly the response

is elastic or viscoelastic whereas a part of the response is plastic and non-recoverable which

appears in the form of permanent deformation.

5

Figure 1.4: Visco Elastic Behavior of Asphalt

1.3 Flexible Pavement Distresses in Pakistan

1.3.1 Rutting

Rutting in asphaltic concrete layer in flexible pavements is a major concern for the highway

authorities in Pakistan which is due to heavy loadings, high temperature and unavailability of

pavement design guidelines suiting to local conditions. It develops gradually with load

repetitions and is reflected on the surface in the form of longitudinal depressions in wheel

paths. Rutting is being observed on almost all of the National Highways and Motorways as

shown in Figure 1.5 and Figure 1.6 which is primarily due to shear flow of material. These

depressions are critical due to the following three reasons:

i) Water is accumulated on the impervious surface causing hydroplaning

ii) With the increase in rut depths, driver loses control on vehicle causing traffic

safety hazards

iii) Premature failure of the pavement which causes considerable economical loss

and inconvenience to road users during long periods of reconstruction and

rehabilitation.

6

Figure 1.5: Rutting in Outer Lane Figure 1.6: Severe Rutting due to Shear Failure

(Kashmir Highway) (Islamabad Highway)

1.3.2 Fatigue

There are many reasons that cause fatigue failure. These include bad quality construction,

inadequate structural design, application of heavier loads than anticipated during design,

stripping at the bottom of hot mix asphalt layer and failure of base, subbase or subgrade

support. Fatigue is a series of interconnected cracks, resulting due to fatigue failure of the

asphaltic concrete surface under repeated traffic loading.

Fatigue cracking instigates either from bottom or from top of the pavement. It initiates at

bottom of the asphaltic concrete layer where the tensile stress is maximum which further

propagates to the surface resulting in one or more longitudinal cracks. These cracks initiate

from the top in areas of high localized tensile stresses due to tires and pavement contact or

due to the asphalt binder aging. Under the action of repeated loadings, the longitudinal cracks

connect and develop multi sided pattern resembling the back of an alligator as shown in

Figures 1.7 and 1.8. Fatigue is an indication of structural failure of the pavement. The cracks

allow moisture infiltration which causes roughness on the road surface and ultimately results

in formation of potholes.

7

Figure 1.7: Fatigue Cracking at Figure 1.8: Fatigue Cracking at

(M-9 North Bound) (M-2 North Bound)

1.4 Solutions to the Rutting Problems in Hot Mix Asphalt (HMA)

Rutting problem is being addressed throughout the world. Solutions have been proposed to

minimize rutting problem by various highway agencies and researchers. Some of them

recommended improvement in quality of materials, while several others suggested use of

innovative materials and a few concluded that solution lies in the development of new mix

design methods. But only a few of the suggested solutions got widespread acceptance and

practical adoption. These include using Crumb Rubber Modified Bitumen (CRMB), SMA,

polymer modifications and adopting Superpave mix design method etc.

CRMB is a combination of selected grades of bitumen and crumb rubber modifier. The

modifier restores the required visco-elastic balance of the asphalt binder, which improves

binder resistance to permanent deformation while maintaining high resistance to fatigue,

thermal and low temperature cracking. CRMB also increases the life of pavement. CRMB

has excellent adhesion to different types of aggregates which therefore diminish rutting,

cracking and deformations. It has excellent resistance to thermal and low temperature

cracking, superior resistance to any form of permanent deformation, better adhesion between

aggregate and binder, overall improved performance in severe climatic conditions, higher

fatigue life of mixes, highly flexible and stable. These conclusions were made by Tiki Tar

Products (2008).

8

Qiu and Lum (2006) utilized aggregate packing concepts to design and quantify aggregate

stone-to-stone contact in SMA. This SMA is expected to provide high resistance to rutting,

maintaining volumetric properties and providing resistance to distresses. The stability and

rutting resistance of SMA is obtained from coarse aggregate stone to stone contact and

proper aggregate packing. Durability of SMA Mix is achieved by proper mix design.

Gilles et al. (2004) carried out a comprehensive research on use of polymer modified bitumen

and concluded that high quality asphalt binder is needed to facilitate pavements to withstand

increasing traffic intensity and axle loads in extreme climatic conditions. Special binders such

as modified bitumen address the rutting problems in asphaltic concrete. Polymer modified

bitumen (PMB) has proved itself giving superior results against the distresses especially the

rutting which occur at extreme temperature conditions.

Superpave (Superior Performing Asphalt Pavements) is the major revolution in pavement

industry in past few years. The Strategic Highway Research Program (SHRP) in USA carried

out a $50 million research project from October 1987 to March 1993 to develop new

guidelines to identify, test, and design asphalt materials. The ultimate product of the SHRP

asphalt research project was that Superpave represented an improved method for identifying

the components of asphaltic concrete, asphalt mixture design and analysis, and asphalt

pavement performance based evaluation as reported by Yildirim, Y. (1996)

9

1.5 Research Objectives

Following were the objectives of the research work;

• Critical analysis of the available information relating to rutting of asphaltic concrete.

• Characterization of the locally available materials such as aggregates and asphalt

binder according to Superpave mix design criteria.

• Establishing performance grades of Asphalt to suit local environmental conditions

which is one of the mile stones in implementing Superpave mix design method in

Pakistan

• Evaluation of the performance of Superpave, Marshall and Stone Mastic Asphalt

(SMA) mixes using Indirect Tensile Modulus Test, Uniaxial Loading Strain Test

(Creep Test), Dynamic Modulus Test and Wheel Tracking Test.

1.6 Scope of Work

The tasks conducted to achieve the objectives of this research are presented in Figure 1.9 as

flow chart.

10

Figure 1.9: Flow Chart Diagram (Scope of Work)

Literature Review

Collection of Materials

Physical Characterization of the Asphalt (Binder)

Physical and Mechanical Characterization of the

Aggregates Collection of Weather Data

Generation of Temperature Zoning Map

Selection of NHA’s Aggregate Gradation

Selection of Optimal Aggregate Gradation Using

Superpave Procedure

Asphalt Content Optimization According to Marshal Mix

Design Procedure

Asphalt Content Optimization According to Superpave Mix

Design Procedure

Preparation of Test Samples @ Optimum Marshall Asphalt

Content

Preparation of Test Samples @ Optimum Superpave

Asphalt Content

Performance Evaluation of Prepared Samples

- Indirect Tensile Modulus Test - Repeated Uniaxial Strain Test - Dynamic Modulus Test - Wheel Tracking Test

Analysis of the data

Conclusion

Recommendations

Selection of Aggregate Gradation

Asphalt Content Optimization According to SMA Design

Procedure

Preparation of Test Samples @ Optimum SMA Content

11

The summary of the chapter breakdown is described in seriatim as follows: Chapter 2 illustrates the critical view of literature relating asphalt properties and

performance evaluation of asphalt against different types of distresses, especially the rutting.

Chapter 3 presents an overview of Superpave Mix Design Method. It includes introduction

to Superpave Asphalt Binder Testing, Formation of Binder Grades, Volumetric Properties of

Superpave Mixes, Moisture Sensitivity Testing, Performance Evaluation of Superpave Mixes

and Comparison of Superpave with Conventional Mixes

Chapter 4 involves Performance Grading of Asphalt and Preparation of Superpave binder

performance grading map. It explains collection of air temperature data across Pakistan from

30 stations for the last 20 years through Pakistan Meteorological Department, analysis of air

temperature data, zoning of PAKISTAN on the basis of pavement temperatures and grade

adjustments according to Superpave criteria for performance grades. Finally a zoning map

has been proposed to be implemented for Pakistan.

Chapter 5 explicates Materials Characterization of materials to be used for the current

research, based on their properties obtained through various tests. Aggregates testing include

exploring conventional mechanical properties, source properties and consensus properties. In

addition, aggregate gradation according to Superpave Specifications is also explained.

Bitumen Testing includes physical properties required according to Superpave Binder

Testing criteria.

Chapter 6 expounds Performance Based Testing of asphaltic concrete samples at different

temperatures, loading frequencies and stress levels. The tests are described one by one with a

12

brief description of the preparation of test samples and testing standard procedure. The

results are then plotted among different variables for an in depth study of the behavior of

different mixes. The tests include Indirect Tensile Modulus using UTM-5P Uniaxial Loading

Strain (Creep Test) using UTM-5P, Dynamic Modulus using NU-14 and Wheel Tracking

Test.

Chapter 7 is a Discussion oriented chapter dealing with a comparative study of different

mixes based on the results obtained through testing. The parameters which are discussed

consist of Modulus of Resilience, Accumulated Strains, Creep Stiffness, Resilient Strain,

Dynamic Modulus, Permanent Strains and Rut Depth.

Chapter 8 concludes the discussion with substantial and favourable recommendations

achieved on the basis of research study.

13

Chapter Two

14

Chapter 2

Literature Review

2.1 Permanent Deformation in Flexible Pavements

Rutting or permanent deformation of a pavement is caused by progressive movement of

material under repeated traffic load through consolidation or plastic flow. Contrary to the

original idea given by AASHO Road Test Report (1962) that rutting occurs primarily due to

lateral movement of the subgrade, studies carried out on rutted pavements by Huber and

Heiman (1987), Anani et al. (1990), Lee et al. (1989), Brown et al. (1990), Parker et al.

(1992) have reported that although rutting may occur as a result of weak underlying layers,

the rutting observed in existing pavements is almost entirely due to the permanent

deformation in the HMA (Hot Mix Asphalt) layers of the pavements. This incidence in

rutting is due to increase in truck tire pressures, axle loads, and traffic volumes as reported in

joint research study performed by AASHTO and FHWA (1987).

Ford and Miller (1988) through rutting studies have shown that pavements with air voids

lower than 3.0 percent tend to rut while those with higher air voids do not, as long as the

aggregate quality is satisfactory. They also concluded that pavements with air voids

considerably lower than 3.0 percent have a propensity to rut severely. Brown and Cross

(1990) reported that HMA (Hot Mix Asphalt) pavements constructed at approximately 7.0 to

8.0 percent air voids are further compacted to approximately 4.0 percent air voids under

traffic loads, if the mix is properly designed.

Pomeroy, C. D. (1978) commented that HMA has both elastic and viscous characteristics and

is referred to as a visco-elastic material. They also added that behavior of asphalt is

dependent on time of loading and temperature. Findley et al. (1976) studied the creep and

relaxation properties of nonlinear viscoelastic materials and concluded that under constant

static or repeated loading, a visco-elastic material undergoes flow or ‘creep’, which includes

15

recoverable and irrecoverable, time dependent and time independent components of

deformation. Furthermore they elucidated that instantaneous elasticity, creep under constant

stress, instantaneous recovery, delayed recovery, and permanent strain can be used to

characterize viscoelastic materials including HMA.

Nair and Chang (1973) worked on creep behaviour of asphalt and stated that under repeated

load in HMA there is a time dependent and time independent component of deformation. The

deformation consists of three components. First recovered at removal of load, another

recovered gradually and the third remaining as permanent strain. It was also reported that

temperature of the HMA at the time of loading and stress level of loading significantly

influenced the response.

2.2 Types of Rutting in Asphaltic Concrete Mouratidis and Freitas (2007) assessed the rutting of the pavement due to asphalt flow. They

found that plastic flow or post-compaction may be regarded as the reason behind pavement

deformation in the asphalt layers. Plastic flow usually occurs at constant volume conditions

and results from the movement of the mix laterally away from the wheel path due to shear

strain whereas the continued compaction of the pavement after construction resulting from

the traffic loads is called post-compaction. They reported that rutting may also be due to

insufficient compaction of the asphalt layers and low bearing capacity of the asphalt layers.

The rutting process is gradual and increases with the increasing number of load applications

and ultimately appears in the form of longitudinal depressions in the wheel path in addition

to small upheavals to the sides. When the surface deformation is a result of subgrade

settlement, the ruts are generally wider. Rutting is most common in warmer climate areas,

heavily trafficked roads, approaches to intersection and climbing lanes. Rut depth in access

of 1 cm poses a safety hazard since it may result in hydroplaning, wheel scatter and vehicle

handling difficulties.

2.2.1 Rutting Due to Densification

Huber and Heiman (1987) performed comprehensive research on causes of rutting and found

16

that densification can also be a significant cause. Due to the additional compaction in the

pavement surface or in any of the underlying layers (base, subbase or subgrade), rutting by

densification occurs after the road is open to traffic. Moreover due to inadequate compaction

during the construction of the pavement, the surface may undergo further compaction under

traffic loading resulting in rutting. Construction of the asphalt concrete pavement is usually

carried out at initial void content of 7 – 8 % which upon further compaction under traffic is

anticipated to reduce at about 4 % after which the conditions may stabilize. Upon uniform

compaction of the asphalt surface by traffic, densification by rutting is not a problem. Most

of the densification occurs in the wheel path with channelized traffic flow creating

longitudinal ruts. Further compaction of the base or subbase due to the under designed

pavement surface or due to the poor subsurface drainage results in the rutting of the

pavement surface. These ruts have a sloping saucer shape cross section and are fairly wide

(750 -1000 mm) as shown in Figure 2.1.

Figure 2.1: Rutting due to Densification

2.2.2 Rutting due to Shear Failure

Huber and Heiman (1987) studied the rutting properties of asphalt mixtures and reported that

asphalt mixtures may be subjected to shear deformation subjected to traffic loading when air

void content is very low i.e., less than 4 %. Signs of mixture instability appear due to the

lateral displacement of the pavement material along shear planes. This type of shear failure

can be in longitudinal and transverse directions. The ruts appear as depressions in the loaded

area in the wheel paths and ridges appear along both the edges of the wheel path. Due to the

tire pressures, resistance to the shear stresses generated in the pavement surface is reduced

17

which results in shear deformation as shown in Figure 2.2. Asphalt type, asphalt content and

weak aggregate skeleton are the main factors responsible for the lack of the shear resistance.

Besides, this type of rutting is also influenced by the temperature and rate of loading as well

as the magnitude of loading. Shear weakness may also result due to the moisture damage.

Figure 2.2: Rutting due to Shear Failure

2.3 Factors Affecting Rutting

Tarefder et al. (2003) explained that the main factors which showed significant contribution

to rutting in asphaltic concrete pavements were binder grade, temperature, gradation,

moisture of test specimens and binder content. Another factor which affects rutting is the

method of mix design. Bahia, H.U. (1993) examined that a variety of mix design methods are

being practiced all over the world e.g. Asphalt Institute Triaxial method of mix design,

Marshall mix design method, Hubbard-field mix design method, Superpave mix design and

Hveem mix design method, etc. Marshall, Superpave and Hveem mix design methods are

most popular among all those are being practised these days. Marshall mix design procedure

(ASTM D 1559) is being practiced locally for the design of asphaltic concrete. The use of

Marshall Mix design procedure for asphaltic concrete is one of the contributing causes to

early distresses developed in Pakistani pavements. The Marshall mix design method does not

take into consideration variation in temperature, loads and material properties, which is its

greatest drawback.

Swami et al. (2004), after comparing both the Superpave and Marshall Mix design methods,

recommended that Marshall Compactor is not able to identify the rutting susceptibility of

18

asphaltic concrete. Roberts et al. (2002) commented that the high degree of shear

vulnerability of asphalt mixes is not well identified by Marshall compactor and compaction

procedure of Marshall mix method does not replicate the actual compaction which occurs

under moving traffic. Due to these drawbacks it was eliminated from ASTM standards in

2004. SHRP (Strategic Highways Research Program) has concentrated on formation of

performance based binder and asphalt mixture specifications. Major aim of SHRP (Strategic

Highway Research Program) asphalt research was to develop such a mix design procedure

that includes performance based binder specifications and performance based testing

procedures.

Brown and Pell (1974) concluded that a continuously graded mixture exhibits less

deformation than a gap graded mixture due to less aggregate interlocking in gap graded

mixture. Evidences show that the effects of rutting can be reduced by use of dense aggregate

gradations. On proper compaction, mixtures with dense or continuous aggregate gradations

are more closely spaced than open or gap graded mixtures and therefore have fewer voids.

Also at higher temperature, the aggregate interlocking becomes more prominent so gap

graded mixtures are more susceptible to rutting at higher temperature which was later on

confirmed by test track results. Surface texture of the aggregate is particularly important for

good rutting resistance in thicker asphalt-bound layers and hotter climates where a rough

surface texture is required. Shape of the particle is also an important factor.

Uge and Van de Loo (1974) performed shear creep test and found that angular aggregate

mixtures were more stable and deformed to minor extent than rounded aggregate mixtures

having same composition and grading. Crushed aggregates produce stiffer mixtures at a

given void content. Use of the “large-stone” mixtures has gathered a lot of interest with the

increased tire pressures, axle loads, and load repetitions.

Davis, R (1988) found that some asphalt pavements constructed with large maximum

aggregate size (1½ in. or larger), soft asphalts, high volume concentrations of aggregate and

low air-void contents are more stable and resistant to rutting. So he recommended that

mixtures made by using larger maximum aggregate size (about 2/3 of layer thickness) are

19

more resistant to rutting subjected to high tire pressures.

Mahboub and Little (1988) found that mixtures containing less viscous asphalts are less stiff

and are more prone to rutting using the uniaxial creep testing. Monismith et al. (1985) also

recommended more viscous asphalt cements in thicker pavements and hotter climates on the

basis of similar observations.

Monismith and Tayebali (1988) examined the relative behavior of mixtures with and without

modifiers. They found that mixtures containing modified asphalt cement showed better

resistance to rutting at high temperatures than the mixture containing the neat asphalt cement.

Resistance to rutting may be improved by the use of modifiers (polymers, microfiollers, etc.)

which make asphalt binder more viscous at higher temperatures without any adverse effect at

low temperature.

Rutting is also influenced by the binder content. Monismith et al. (1985) recommended that

asphalt content which may produce the air void content of nearly 4 percent may be suitable.

An absolute value of 3 percent air voids was recommended to prevent rutting and instability.

Mahboub and Little (1988) found that rutting increases with the increase in asphalt content

producing lower air voids since the void space is filled with asphalt. The increase in asphalt

content can be said equivalent to the introduction of lubricants between aggregate particles

otherwise separated by a very tight network of air voids resulting in more susceptibility to

permanent deformation.

Cooper et al. (1985) studied that low voids in mineral aggregates (VMA) results in good

resistance to permanent deformation. Rutting resistance of asphalt mixture can also be

improved by reducing air voids up to a certain limit. Higher compaction energy results in a

low air void content in the field.

Uge and Van de Loo (1974) found that at moderate or high temperature, the relative

displacements of mineral particles occurring during laying or compaction under prolonged

20

loading may accelerate rutting. Therefore, they recommended the use of mixtures with low

workability and those prepared with heavy rollers in order to improve the arrangement of

mineral skeleton and internal friction and hence to minimize rutting potential. So they

concluded that harsh mixtures that are well compacted after laying will be highly resistant to

rutting.

Linden and Van der Heide (1987) evaluated that the degree of compaction is an important

parameter for the performance of mixtures. Thus well-compacted, well-designed and well-

produced mixture has better durability and mechanical properties. Compaction also plays an

important role for the preparation of specimens for laboratory evaluation in order to better

simulate orientation and interlocking of aggregate particles, the extent of inter-particle

contact, air-void content and void structure, and number of interconnected voids, with the

actual field compaction.

Von Quintus et al. (1988) determined the extent to which various types of laboratory

compaction simulates field conditions. The study compared field cores with laboratory

specimens compacted using the Texas gyratory-shear compactor, the California kneading

compactor, the mobile steel wheel simulator, the Arizona vibratory/kneading compactor, and

the Marshall hammer. The compaction devices on the basis of their simulation with the field

cores are ranked by the researchers as;

1) Texas gyratory-shear compactor,

2) California kneading compactor and mobile steel wheel simulator,

3) Arizona vibratory/kneading compactor, and

4) Marshall Hammer.

Sousa and Chan (1991) concluded on the basis of above research studies that laboratory

fabricated specimens should simulate the field compaction due to repeated traffic in order to

evaluate the permanent deformation characteristics.

21

The above discussed factors updated by Mouratidis and Freitas (2007) have been

summarized in Table 2.1 below.

Table 2.1: Factors Affecting Rutting of Asphalt-Concrete Mixtures (After Sousa et al.

(1991))

Factor Change in Factor Effect of Change in Factor on Rutting Resistance

Surface texture Smooth to rough Increase

Gradation Gap to continuous Increase

Shape Rounded to angular Increase Aggregate

Size Increase in maximum size Increase

Binder Stiffness Increase Increase

Binder content Increase Decrease

Air void content b Increase Decrease

VMA Increase Decrease c Mixture

Method of compaction Up to optimum 95-97 % Increase

Temperature Increase Decrease

State of stress/strain Increase in tire contact pressure Decrease

Load repetitious Increase Decrease

Test field conditions

Water Dry to wet Decrease if mix is water sensitive

2.4 Rutting Potential of Different Mixes Palit et al. (2004) investigated mixes of different gradation to compare their fatigue and other

characteristics. They used Superpave gradation, Ministry of Surface Transport of India’s

gradation and One Gap gradation. They found that Superpave mixes gave better overall

performance compared to the mixes of other gradation. Different performance testing proved

the superiority of crumb rubber modified mixes in terms of improved fatigue and different

pavement characteristics.

22

Collop et al. (1995) treated permanent deformation or rutting in bituminous pavements as a

linear visco-elastic flow phenomenon and found that permanent deformation per wheel pass

is directly proportional to the static axle load and inversely proportional to the vehicle speed.

The phenomenon is quite useful for investigating the road damaging potential of heavy

vehicles and evaluating important trends.

2.5 Performance of SMA against Rutting

Chui and Li (2006) studied the performance of SMA using Ground Tire Rubber (GTR) in the

lab. They concluded that the SMA mixes containing Asphalt Rubber (AR-Asphalt containing

blended ground tire rubber) were not significantly different from conventional SMA mixtures

with respect to moisture susceptibility. But rutting resistance of AR-SMA, mixture was better

than conventional SMA at 60 oC.

Qiu and Lum (2006) utilized aggregate packing concepts to design and quantify aggregate

stone-to-stone contact in SMA. This SMA is expected to provide high resistance to rutting

maintaining volumetric properties and providing resistance to distresses. The stability and

rutting resistance of SMA is obtained from coarse aggregate stone to stone contact and

proper aggregate packing. Durability of SMA mix is achieved by proper mix design. The test

results proved that SMA mixtures had excellent rutting resistance characteristics. A positive

correlation existed between the rutting obtained from wheel tracking test and deformation

strain from uniaxial creep test.

Asi, I. M. (2007) compared SMA mixtures and conventional dense graded asphalt mixtures

on the basis of laboratory performance testing which included Marshal stability, loss of

Marshall stability, split tensile strength, loss of split tensile strength, resilient modulus,

fatigue and rutting. Optimum Binder contents were 5.3% for control mixes and 6.9% for

SMA mixtures, 0.3% mineral fibre by weight of mixture were used to avoid drain down of

excess asphalt. SMA mix proved its superiority over the conventional mixes showing better

resilience, rutting resistance and durability.

23

2.6 Standard Types of Performance Testing Methods Brown et al. (2001) comprehensively evaluated the test methods which could be used as

standard to evaluate performance potential. They evaluated the existing information on

permanent deformation, fatigue cracking, low-temperature cracking, moisture susceptibility,

and friction properties but main emphasis was laid on permanent deformation. They

compared and reviewed the available tests concerning specific contemplations, such as

simplicity, test time duration, cost of the equipment, availability of data to support use,

published test method, available criteria etc.

They chose tests types with ultimate potential to simulate the field conditions during

performance evaluation of HMA, validated potential test types based on documented studies

and evaluated if the selected test methods illustrate the right trend in permanent deformation

performance. Methods that had been used to evaluate permanent deformation were discussed

in detail by them. A summary of advantages and disadvantages of each of the tests

considered for permanent deformation (rutting) has been shown in Table 2.2 reproduced

from Brown et al. (2001).

Numerous tests were evaluated for measuring rutting potential. Tests which were suggested

for immediate acceptance included the following three wheel tracking tests: Asphalt

Pavement Analyzer (APA), Hamburg Wheel-Tracking Device (HWTD), and French Rutting

Tester (FRT).

24

Table 2.2 Standard Types of Performance Based Testing Methods and Equipment (After Brown et al. (2001))

Test Method Sample

Dimension Advantages Disadvantages

Diametral Static (creep)

4 in. diameter × 2.5 in. height

• Test is easy to perform • Equipment is generally available in most labs • Specimen is easy to fabricate

Diametral Repeated Load


• Test is easy to perform • Specimen is easy to fabricate

Diametral Dynamic Modulus


• Specimen is easy to fabricate • Non destructive test

Fund

amen

tal:

Dia

met

ral T

ests

Diametral Strength Test


• Test is easy to perform • Equipment is generally available in most labs • Specimen is easy to fabricate • Minimum test time

• State of stress is nonuniform and strongly dependent on the shape of the specimen • Maybe inappropriate for estimating permanent

deformation • High temperature (load) changes in the specimen shape affect the state of stress and the test measurement significantly • Were found to overestimate rutting • For the dynamic test, the equipment is complex

Uniaxial Static (Creep)

4 in. diameter × 8 in. height & others

• Easy to perform • Test equipment is simple and generally available • Wide spread, well known • More technical information

• Ability to predict performance is questionable • Restricted test temperature and load levels does not simulate

field conditions • Does not simulate field dynamic phenomena • Difficult to obtain 2:1 ratio specimens in lab

Uniaxial repeated Load


• Better simulates traffic conditions

• Equipment is more complex • Restricted test temperature and load levels does not simulate field conditions • Difficult to obtain 2:1 ratio specimens in lab

Uniaxial Dynamic Modulus


• Non destructive tests • Equipment is more complex • Difficult to obtain 2:1 ratio specimens in lab

Fund

amen

tal:

Uni

axia

l Tes

ts

Uniaxial Strength Test


• Easy to perform • Test equipment is simple and generally available • Minimum test time

• Questionable ability to predict permanent deformation

(Continued)

25

Table 2.2 Standard Types of Performance Based Testing Methods and Equipment

(Continued)

Test Method Sample Dimension

Advantages Disadvantages

Triaxial Static (creep confined)


• Relatively simple test and equipment • Test temperature and load levels better simulate field conditions than unconfined • Potentially inexpensive

• Requires a triaxial chamber • Confinement increases complexity of the test

Triaxial Repeated Load

4 in. diameter × 8 in. height

others

• Test temperature and load levels better simulate field conditions than unconfined • Better expresses traffic conditions • Can accommodate varied specimen sizes • Criteria available

• Requires a triaxial chamber • Confinement increases complexity of the test

Triaxial Dynamic Modulus


• Provides necessary input for structural analysis • Non destructive test

• At high temperature it is a complex test system (small deformation measurement sensitivity is needed at high temperature) • Some possible minor problem due to stud, LVDT arrangement. • Equipment is more complex and expensive • Requires a triaxial chamber

Fund

amen

tal:

Tria

xial

Tes

ts

Triaxial Strength

4 or 6 in. diameter × 8 in. height & others

• Relative simple test and equipment • Minimum test time

• Ability to predict permanent deformation is questionable • Requires a triaxial chamber

26




SST Frequency Sweep Test – Shear Dynamic Modulus


• The applied shear strain simulate the effect of road traffic • AASHTO standardized procedure available • Specimen is prepared with SGC samples • Master curve could be drawn from different temperatures and frequencies • Non destructive test

• Equipment is extremely expensive and rarely available • Test is complex and difficult to run, usually need special training • SGC samples need to be cut and glued before testing

SST Repeated Shear at Constant Height


• The applied shear strains simulate the effect of road traffic • AASHTO procedure available • Specimen available from SGC samples

• Equipment is extremely expensive and rarely available • Test is complex and difficult to run, usually need special training • SGC samples need to be cut and glued before testing • High COV of test results • More than three replicates are needed

Fund

amen

tal:

Shea

r Tes

ts

Triaxial Shear Strength Test


Short test time • Much less used • Confined specimen requirements add complexity

Marshall Test 4 in. diameter × 2.5 in. height or 6 in. diameter × 3.75 in. height

• Wide spread, well known, standardized for mix design • Test procedure standardized • Easiest to implement and short test time • Equipment available in all labs.

• Not able to correctly rank mixes for permanent deformation • Little data to indicate it is related to performance

Hveem Test 4 in. diameter × 2.5 in. height

• Developed with a good basic philosophy • Short test time • Triaxial load applied

• Not used as widely as Marshall in the past • California kneading compacter needed • Not able to correctly rank mixes for permanent deformation

GTM Loose HMA • Simulate the action of rollers during construction • Parameters are generated during compaction • Criteria available

• Equipment not widely available • Not able to correctly rank mixes for permanent deformation

Empi

rical

Tes

ts

Lateral Pressure Indicator

Loose HMA • Test during compaction • Problems to interpret test results • Not much data available

(Continued)

27




Asphalt Pavement Analyzer

Cylindrical 6 in. × 3.5 or 4.5 in. or beam

• Simulates field traffic and temperature conditions • Modified and improved from GLWT • Simple to perform • 3-6 samples can be tested at the same time • Most widely used LWT in the US • Guidelines (criteria) are available • Cylindrical specimens use SGC

• Relatively expensive except for new table top version

Hamburg Wheel-Tracking Device

10.2 in. × 12.6 in. × 1.6 in.

• Widely used in Germany • Capable of evaluating moisture induced damage • 2 samples tested at same time

• Less potential to be accepted widely in the United States

French Rutting Tester

7.1 in. × 19.7 in. × 0.8 to 3.9 in.

• Successfully used in France • Two HMA slabs can be tested at one time

• Not widely available in U.S.

PURWheel 11.4 in. × 12.2 in.× 1.3, 2, 3 in.

• Specimen can be from field as well as lab-prepared

• Linear compactor needed • Not widely available

Model Mobile Load Simulator

47 in. × 9.5 in.× thickness

• Specimen is scaled to full-scaled load simulator

• Extra materials needed • Not suitable for routine use • Standard for lab specimen fabrication needs to be developed

RLWT 6 in. diameter × 4.5 in. height

• Use SGC sample • Some relationship with APA rut depth

• Not widely used in the United States • Very little data available

Sim

ulat

ive

Test

s

Wessex Device 6 in. diameter × 4.5 in. height

• Two specimens could be tested at one time • Use SGC samples

• Not widely used or well known • Very little data available

Fundamental diameteral, uniaxial, triaxial, shear, empirical and simulative tests were studied with

sample dimensions, their advantages and disadvantages. Indirect Tensile Modulus test using UTM-

5P can be used for the assessment of Asphaltic Concrete Modulus of Resilience (MR), whereas

Uniaxial repeated loading strain test using UTM-5P test can be used for assessing rutting potential

of Asphalt mix. Uniaxial Dynamic Modulus Test using NU-14 is suitable to study behavior of

Asphaltic Concrete under dynamic loading whereas rutting susceptibility of Asphalt mix is

checked through Wheel Tracking Machine. All of the above mentioned equipment is available in

Taxila Institute of Transportation Engineering (TITE).

28

Chapter Three

29

Chapter 3

Superpave Mix Design Method

3.0 Introduction

The Superpave (SUperior PERforming Asphalt PAVEments) mix design method was

developed to provide highway agencies, engineers and contractors such a system that

would perform superior under diverse temperature ranges and traffic loads. Superpave

which was developed by the researchers of Strategic Highway Research Program (SHRP)

mainly addresses two pavement distresses i.e. permanent deformation (rutting) and low

temperature cracking. The distinctive aspect of the Superpave system is its test

procedures which have direct correlations with the field performance. Superpave has

advanced system for identifying asphalt binders and mineral aggregates, designing

asphalt mix and pavement performance prediction.

The asphalt binder specifications help selecting asphalt binder suitable for the maximum

and minimum temperatures and the heavy traffic volumes for a particular pavement

section. This is perhaps a unique trait of the Superpave that different binders are

suggested to be used in various parts of the country and for different types of highways.

The binders to be used in hot areas need modification to meet the performance grade

requirement for those specific locations.

3.1 Superpave Asphalt Binder Tests

Asphalt Institute in Superpave Series No. 1 classifies three stages of asphalts life; original

state, after mixing and construction, and finally in service. To quantify the performance

of the asphalt in each of the three stages, Superpave binder tests are used. To simulate

them in service aging, the Pressure Aging Vessel (PAV) is used whereas to simulate the

binder aging that occurs during mixing and construction, Rolling Thin Film Oven

(RTFO) test is used. The binder’s aging condition used in the Superpave binder tests is

30

shown in the Table 3.1 (Reproduced from Asphalt Institute’s Superpave Series No. 1).

The tests relations to performance are shown in Figure 3.1(Reproduced from Asphalt

Institute’s Superpave Series No. 1).

Table 3.1 Superpave Binder Test Aging Condition

Superpave Binder Test Binder Condition Dynamic Shear Rheometer (DSR) Original Binder RTFO – Aged Binder PAV – Aged Binder Rotational Viscometer (RV) Original Binder Bending Beam Rheometer (BBR) PAV – Aged Binder Direct Tension Tester (DTT) PAV – Aged Binder

Figure 3.1: Superpave Laboratory Tests with Relation to Performance

3.1.1 Dynamic Shear Rheometer (DSR)

McGennis et al. (1995) found that loading time and temperature are the factors upon

which the asphalt behavior depends. Dynamic Shear Rheometer (DSR) is a device that

31

tests the asphalt binder behaviour considering both of the above mentioned factors. The

DSR also known as Dynamic Rheometer or Oscillatory Shear Rheometer shown in

Figure 3.6(Reproduced from Asphalt Institute’s Superpave Series No. 1), when used to

test asphalt binders, measures the properties such as complex shear modulus (G*) and

phase angle (δ) (known as rheological properties) at different temperatures as shown in

Figure 3.2(Reproduced from Asphalt Institute’s Superpave Series No. 1).

Figure 3.2: Dynamic Shear Rheometer Operation

Asphalt Institute in Superpave Series No. 1 describes the operation of DSR. Asphalt

sample of required quantity is placed between two parallel plates. One of the plates is

fixed and the other oscillates. The plate oscillations cause the center line of the plate at

point A to move to the point B. The plate then moves back and passes A to reach point C.

From point C it goes back to point A. This completes one cycle which is continuously

repeated during the whole operation. The speed of oscillation is at a frequency of 10

radians per second (approximately 1.59 Hz). Stress and strain measurements are made

during each cycle.

Anderson et al. (1995) studied that both elastic and viscous behavior is characterized by

DSR by the measurement of rheological properties of asphalt binders. Among these

properties, the complex shear modulus (G*) measures the total resistance of a material to

deformation when exposed to repeated pulses of shear stress. Its two components are

elastic (recoverable) and viscous (non recoverable). The other property is phase angle

which gives an indication of the relative amounts of recoverable and non recoverable

32

deformation. Both of the above mentioned properties highly depend upon the frequency

of loading and temperature. Asphalt has no recoverable or rebounding capacity at high

temperature and behaves like viscous fluids. For the case, the viscous component could

be used to represent the asphalt and no elastic component of G*, since δ = 90°. On the

other hand, asphalt behaves like elastic solids which rebound from deformation

completely at very low temperatures. The elastic component is used to represent the

asphalt condition with no viscous component, since δ = 0°.

Anderson et al. (1995) found that asphalt binder behaves both as viscous liquids and

elastic solids at normal pavement temperatures. Hence DSR completely visualizes the

behavior of asphalt by the measurement of the G* and δ. In Figure 3.3 (Reproduced from

Asphalt Institute’s Superpave Series No. 1), G1* and G2* are the complex moduli of

asphalts 1 and 2 respectively. Figure 3.3 shows that although both the asphalts behave

visco elastically and has the same G, but the elasticity of Asphalt 2 is more than 1,

because of its smaller phase angle so the Asphalt 2 with the larger elasticity will recover

much more deformation from an applied load. So both G* and δ are needed to assess the

asphalt behavior.

Figure 3.3: Viscoelastic Behavior of Binder

According to Kennedy et al. (1995) an asphalt specimen with a disk shape and diameter

equal to the oscillating plate of DSR is required for testing. Proper asphalt specimen

33

thickness between the fixed plate and the oscillating plate must be made by adjusting gap

between two plates. After the plates are mounted in the Rheometer and before mounting

the asphalt sample, the gap between two plates must be set. A micrometer wheel is used

for precise adjustment of the gap. In binder tests, two oscillating plates with different

diameter and corresponding gap thickness are used. Both the diameter and the thickness

depend upon the aged state of the asphalt being tested. 25mm diameter plate and a gap

thickness of 1000 micron are required for RTFO aged and original (unaged) binders

whereas a diameter of 8mm and a gap of 2000 microns gap are required to test PAV-aged

binders. An extra 50 microns gap is added to the 1000 or 2000 microns before mounting

the specimen. Test specimen is prepared by heating the asphalt binder until fluid, stirring

to achieve occasionally to remove air bubbles and a homogenous sample. The upper limit

of temperature is 163°C with modified asphalt binders requiring higher temperature than

the unmodified binders. Different methods are used for specimen preparation but

commonly by pouring the asphalt binder sample within appropriate diameter and

thickness moulds for testing as shown in Figure 3.4 (Reproduced from Asphalt Institute’s

Superpave Series No. 1). The sample must be removed after 2 hours before loading into

DSR as lighter constituents of the asphalt binder sample may be absorbed by the silicone.

Figure 3.4: DSR Moulds, Specimens, Plates and Spindles

After placement of asphalt, the specimen is flushed with the plates by trimming its

projected edges so that the extra 50 microns is dialed out bringing the gap to its desired

34

value. Slight bulging of the specimen will occur as shown in Figure 3.5 (reproduced from

Asphalt Institute’s Superpave Series No. 1). Rheometers are provided with a precise

mean of controlling sample temperature. A circulating fluid bath or a forced air oven is

used for this purpose. Water is used as a fluid in circulating bath and circulated through a

temperature controller whereas in air ovens, air is used, which surrounds the sample

during testing. In any case, the temperature must be uniform and varies by no more than

1°C across the gap.

Figure 3.5: Asphalt Sample Configuration in DSR.

According to Solaimanian et al. (1995) after stabilization of the test temperature, the

specimen temperature is allowed to equilibrate for a minimum of additional 10 minutes.

Thermistors placed between parallel plates are used to verify temperatures which are

wrapped with very thin silicone rubber sheeting material. The DSR test parameters are

computer controlled and the results are recorded. The DSR is set to apply a constant

oscillating stress and measure the resulting strain and time lag. The oscillation speed is 10

radians/second according to Superpave specifications. The operator sets an approximate

shear strain which varies from 1-12% depending upon the binder aged state being tested.

Strain values of 10 -12% are used for original and RTFO aged binders whereas 1% strain

is used for PAV-aged binders. In any case, to keep the binder response as linear

viscoelastic, strain values must be small. At these values of strain, there is no virtual

effect on G*.According to Solaimanian et al. (1995) the specimen is loaded for 10 cycles

in order to condition the sample. During this period, Rheometer measures the stress

corresponding to the set shear strain and the stress is maintained during the entire test.

35

Shear strain may vary to keep constant stress during test and is controlled by Rheometer

software. Ten additional cycles are applied after 10 conditioning cycles to obtain test

data. The software computes G* and δ from the applied stress and resulting strain

relationship and reports it.

Figure 3.6: Dynamic Shear Rheometer

Totally elastic and totally viscous behavior is shown in Figure 3.7 (reproduced from

Asphalt Institute’s Superpave Series No. 1).

Figure 3.7: Stress-Strain Output

36

Asphalt Institute in Superpave Series No. 1 defines the ratio of the total shear stress to

total shear strain as the complex shear modulus (G*). Phase angle is related to time lag

between the applied stress and the resulting strain or the applied strain and the resulting

stress. The time lag or the phase angle is zero for a perfectly elastic material, where an

applied load causes an immediate response. Time lag between load and response is

typically large for viscous material where the phase angle is 90°. Asphalt binders lie

between these two extremes as they behave as a viscoelastic material at normal

temperature and the DSR shows the response as shown in Figure 3.8 (reproduced from

Asphalt Institute’s Superpave Series No. 1)

Figure 3.8: Stress- Strain Response of a Visco elsatic Material

The formulas used to calculate maximum shear stress and maximum shear strain are

shown in Figure 3.9 (reproduced from Asphalt Institute’s Superpave Series No. 1).

37

Figure 3.9: Asphalt Specimen Calculations

Only G* and δ are required for Superpave specifications, although DSR is capable of

providing much more information. There are two forms of G* and δ that are used in the

binder specifications. Permanent deformation for original binder is governed by limiting

the G*/sin δ at the test temperature to values greater than 1.00 kPa and 2.20 kPa after

RTFO aging. For fatigue cracking the governing limit of G* sin δ of for pressure aged

material is less than 5000 kPa at the test temperature.

3.2 Formation of Binder Grades

Research by Anderson et al. (1995) evaluated previous grading systems with Superpave

binder specifications. Previous grading systems were based on the empirical relationships

between physical properties and the observed performance. The Superpave binder

specifications are based directly on the performance and are selected on the basis of the

climate in which the pavement will serve. Among various binder grades, the distinction is

the specified maximum and minimum temperatures meeting the requirements. A binder

classified as a PG 64 – 10 means that the binder will meet the high temperature physical

property requirements up to a temperature of 64˚C and the low temperature physical

property requirements down to -10˚C.

38

The adjustment of high traffic grades for traffic loading and speed is called “grade

bumping”. The AASHTO’s grade-bumping policy is presented in Table 3.2. The

selection procedure for the asphalt binder is for typical highway loading conditions which

assume that the pavement is subjected to a design number of fast, transient loads. The

speed of loading additionally affects the performance for high temperature design

situation, controlled by the specific properties related to permanent deformation.

Asphalt Institute in Superpave Series No. 2 specifies that Superpave additionally requires

the selected high temperature binder grade for slow and standing load applications. The

binder would be selected one high temperature grade higher for slow moving design

loads and two high temperature grades higher for standing design loads. Also Superpave

requires shift for extraordinarily high number of heavy traffic loads. The binder would be

selected one high temperature binder grade higher than the selection based on climate

when the design traffic is expected to be between 10,000,000 and 30,000,000 equivalent

single axle loads (ESAL) and for more than 30,000,000 ESAL, the binder must be

selected one temperature grade higher than the selection based on the climate. The

adjustment to the Binder PG Grade is given in Table 3.2 (reproduced from Asphalt

Institute’s Superpave Series No. 2)

Table 3.2: Binder Selection on the basis of Traffic Speed and Traffic Level

Adjustment to Binder PG Grade

Traffic Loading Rate Design ESALs (million)

Standing Slow Standard

< 0.3 -(1)

0.3 to < 3 2 1

3 to < 10 2 1

10 to < 30 2 1 -(1)

≥ 30 2 1 1

1. Consideration should be given to increasing the high temperature grade by one grade equivalent.

39

Anderson et al.(1995) showed that the pavement performance cannot be guaranteed by

the conservative binder selection. Performance of the road against fatigue cracking is

significantly affected by the pavement structure and the traffic. Whereas rutting is greatly

influenced by the aggregate properties. The cracking of the pavement at low temperature

is significantly related to the binder properties. Therefore, while selecting binders, a

compromise has to be made among various factors.

3.3 Volumetric Properties of Superpave Mixes

The volumetric properties of Superpave mixes are air voids, voids in mineral aggregates

and void filled with asphalt. The volumetric component diagram of HMA is shown in

Figure 3.10. These properties indicate the performance of the Superpave mixes in the

field. The volumetric properties are usually determined from the Superpave gyratory

compactor test specimens by simulating the effect of traffic on an asphalt pavement.

Figure 3.10: Component Diagram of Compacted HMA Specimen

40

3.3.1 Percent VMA in compacted Paving Mixture

Asphalt Institute in Superpave Series No. 2 defines the intergranular void space between

the aggregate particles in a compacted paving mixture. It includes the air voids and the

effective asphalt content, expressed as a percent of the total volume as Percent Void in

Mineral Aggregates (VMA). The objective is to furnish enough space for asphalt binder

so as to provide adequate adhesion required to bind the aggregate but without bleeding as

the asphalt expands on the rise of temperature. It is calculated by subtracting the

aggregate volume determined by its bulk specific gravity from bulk volume of the

compacted paving mixtures so we can say that VMA is expressed as a percentage of the

bulk volume of the compacted paving mixture.

For mix composition determined on the basis of percent by mass of total mixture:

sPsbGmbG

VMA ×−=100 ---------------------------------------------------------------- (3.1)

Where,

VMA = voids in the mineral aggregate, percent of the bulk volume,

Gsb = bulk specific gravity of total aggregate

Gmb = bulk specific gravity of the compacted mixture

Ps = aggregate content, percent by mass of total mixture

For the mix composition determined on the basis of percent by mass of aggregate:

100100

100100 ×+

×−=bPsG

mbGVMA ---------------------------------------------- (3.2)

Where,

Pb = asphalt content, percent by mass of the aggregate.

41

Specified minimum values for VMA at the design air void content of four percent are a

function of nominal maximum aggregate size. The values are shown in the Table 3.3

(reproduced from Asphalt Institute’s Superpave Series No. 2)

Table 3.3: Superpave Volumetric Mixture Design Requirements

Required Density (% of Theoretical

Maximum Specific Gravity)

Voids – in – the Mineral Aggregates (Percent), minimum

Nominal Maximum Aggregate Size (mm)

Design ESALs

(million) NInitial Ndesign Nmax

37.5 25.0 19.0 12.5 9.5

Voids Filled with

Asphalt

Dust – to – Binder

Ratio

< 0.3 ≤ 91.5 70 - 80

0.3 to < 3 ≤ 90.5 65 - 78

3 to < 10

10 to < 30

≥ 30

≤ 89.0 96.0 ≤ 98.0 11.0 12.0 13.0 14.0 15.0

65 - 75

0.6 – 1.2

3.3.2 Percent VFA in Compacted Mixture:

The percentage of the voids in mineral aggregates that contain asphalt, and not the

absorbed asphalt is called Voids filled with asphalt (VFA). It is determined using the

equation 3.3.

VMAaVVMA

VFA−

×=100 ----------------------------------------------------------------- (3.3)

Where,

VFA = Voids filled with asphalt, percent of VMA

VMA = Voids in mineral aggregates, percent of the bulk volume

Va = Air voids in compacted mixture, percent of total volume

42

The acceptable range of VFA at four percent air voids is a function of traffic level and is

given in the Table 3.3.

3.3.3 Percent Air Voids in compacted Mixture:

The small air spaces between the coated aggregate particles in the total compacted paving

mixture are called air voids. It can be determined by using the equation 3.4.

mmGmbGmmG

aV−

×=100 ------------------------------------------------------------ (3.4)

Where,

Va = air voids in compacted mixture, percent of total volume

Gmm = maximum specific gravity of paving mixture (as determined directly for

a paving mixture by ASTM D2041 / AASHTO T209)

Gmb = bulk specific gravity of compacted mixture

3.4 Performance Evaluation of Superpave Mixes

There is still a question in mind about the performance test for Superpave mix. FHWA in

collaboration with the University of Maryland is now working to find a simple test

procedure that would offer the highway agencies an effective, simple and economical

way to assess the performance of Superpave mixes. Proposed test would be based on the

fundamental engineering properties of the mix. Simple Performance test would have the

capability to work in different climates and to test different type of materials

Asi, I. M. (2007) evaluated Superpave mix and compared it with the conventional

Marshall mix. Samples for both mixes were prepared at optimum asphalt content and

aggregate gradations. Dynamic creep, static creep, resilient modulus and moisture

sensitivity testing were selected as performance based testing. Superpave mix showed

overall better performance as compared to the Marshall Mix.

43

Swami et al. (2004) compared Superpave and Marshall Methods of asphalt mix design.

They found that Marshall Compactor was unable to predict the rutting resistance of the

mix. They also revealed that Superpave Gyratory Compactor could compact the

specimens in the same way as actual compaction under the action of moving vehicles at

different temperature and loading conditions.

Kansas Department of Transportation (KDOT) during full implementation of Superpave

mixture designs for their highways construction performed full scale performance

evaluation of Superpave mixes using accelerated load testing facility. Superpave mixes

do not have any mechanistic test to capture the field performance. Therefore it is a dire

need to have critical stress and strain evaluation method for Superpave mixes. KDOT

sought to address the issue of Superpave Mix performance using Kansas Accelerated

Testing Laboratory (K-ATL) at Kansas State University (Zhong et al.). They used two

different types of Superpave mixes with 15% and 30% sand. Evaluation was done under

the action of different load intensities and combinations. Rutting damage analysis

revealed relationship between number of loading cycles and rut depth (mm). Rutted

vertical profiles showed that rutting occurred either due to the densification or shear flow.

According to Pennsylvania Transport Institute (PTI), two test procedures for performance

evaluation of Superpave mixes under consideration are Superpave Shear Tester and

Indirect Tensile Tester. However, according to FHWA, it would be a supplement and not

a replacement of the existing Superpave Performance test procedures. The confined

Dynamic Modulus Test applies lateral confining pressure to the asphalt specimen of 4 in.

x 8 in. But it can also be used for smaller specimen heights with success as reported by

Brown et al. (2001). NCHRP Project 9-29 demands that the testing equipment must be

capable of conducting the following tests:

1. Static Creep Test.

2. Repeated Load Uniaxial Compression Test.

3. Dynamic Modulus Test for Permanent Deformation.

4. Dynamic Modulus Test for Fatigue Cracking.

44

3.5 Comparison of Superpave with Conventional Mixes

According to Asphalt Institute (1965), Hubbard – Field Method was the first Asphalt Mix

design method developed to design sand – asphalt mixtures and then later on modified for

aggregates. The drawbacks of using this method are for mixes containing aggregate sizes

larger than about ½ in. if the mould diameter to maximum particle size ratio is to be

maintained at 4:1.Many queries remained about what the test actually modeled relative to

the performance of paving mixtures. Due to these limitations, other design methods

moved forward.

In the late 1920s, on many of the rural roads, the California Division of Highways started

the use of combination of aggregates and the asphaltic oil mixed either in a plant or on

the road itself, spread by blade and then compacted by traffic. The mix was referred to oil

mix which was a compromise between the cheaper low performance penetrative method

(asphalt oil sprayed on a roadway surface of unbound particles) and more expensive high

performance HMA. The design of these oil mixes necessitated the determination of the

correct amount of oil based on the aggregate surface area which in turn could be

determined from gradation as reported by Vallerga and Lovering (1985). Even with the

determination of the right oil content, roads containing hard glassy surface textured

aggregates deformed excessively under load whereas, roads containing rough irregular

surface texture aggregates proved more stable. For the reason, Hveem developed

Stabilometer, a device that would measure stability. Another problem was that

compaction of the specimens carried out in the laboratory did not produce the same

readings as those obtained from the field cores. For this reason, California Kneading

Compactor was developed for the close simulation of the compaction produced by the

rollers in the field. When compared to the other design methods, the two biggest

differentiating aspects of the Hveem method are the kneading compactor and the Hveem

Stabilometer according to Vallerga and Lovering (1985).

The preparation and testing of the laboratory specimens by the Hveem design procedure

required equipment that was too expensive to be purchased for the laboratories. Therefore

the Marshall method of mix design was preferred over the Hveem design procedure for a

45

large majority of the hot mix asphalt industry. Marshall Method primarily addresses the

determination of the asphalt binder content. The advantages of this method are the

determination of density and the void properties of the asphalt mixtures. In addition the

equipment required for the Marshall Mix Design Method is relatively inexpensive and

portable and thus lends itself to remote quality control operations. Side by side, the

disadvantages of this method are that impact compaction used with the Marshall method

does not simulate mixture densification as it occurs in the real pavement. Also Marshall

Stability does not adequately estimate the shear strength of HMA. So there was a

growing feeling among the asphalt technologists that Marshall Method has outlived its

usefulness for modern asphalt mixture design as reported by White, T. D. (1985).

The Superpave mix design method addresses all the elements of the mix design and was

designed to replace the Hveem and Marshall methods. The design system integrates

material selection and mix design into procedures based on project’s climate, design

traffic and age which are known to be the most critical factors affecting asphalt

performance in pavements according to Bahia and Anderson (1994). The mix design

method is based on the properties of the asphalt binder and aggreagates and also on the

volumetric properties of the hot mix asphalt (HMA) which were common to Marshall and

Hveem design methods. The compaction devices used for Hveem and Marshall

procedures have been replaced by a gyratory compactor and the compaction effort in mix

design is tied to expected traffic. The performance-grading (PG) system used in

superpave mix design method is considered better over the viscosity and penetration

systyem as the conditions at which the testing is carried out have close simulation with

the actual pavement conditions. According to Roberts et al. (2002), it predicts much

improved reliability as it considers the engineering parameters related to the actual failure

mechanism leading to pavement deterioration.

46

Chapter Four

47

Chapter 4

Performance Grading of Asphalt

4.0 Introduction

Binder plays a crucial role in asphalt performance, due to which it has been given

immense importance by the asphalt industry. Binder grading systems are used to

characterize binders based on their physical properties. As reported by Roberts et al.

(2002), three principal asphalt binder grading systems are being practiced in pavement

industry, i.e. Penetration, Viscosity and Performance Grading. The first two have

limited ability for complete asphalt binder characterization, where as Superpave mix

design system addresses hot mix asphalt pavement performance based issues such as

rutting, fatigue and thermal cracking.

The basic inspiration behind Superpave performance grading (PG) is that a Hot Mix

asphalt binder’s properties should be associated with prevailing climatic conditions

and aging considerations. McGennis et al. (1995) performed a comprehensive

research study for United States Department of Transportation (USDOT)

“Background of Superpave mixture design and analysis”, in which they formulated

basic guidelines for binder’s performance grading based on maximum and minimum

pavement design temperatures.

Regarding temperature selection the hottest seven day period was selected and the

average maximum air temperature was calculated for each year. Then average of

seven hottest temperatures across 20-year air temperature data was taken which

presented the maximum air temperature data for a particular area. The criterion for

minimum air temperature was somewhat different in the sense that for each year

coldest day’s temperature was selected and from 20 years temperature data one

temperature was selected which was the lowest. The conversion of air temperatures

into pavement temperatures was the next step as for the selection of asphalt binder

grades, the design temperatures were the pavement temperatures not the air

temperatures.

48

Superpave recommends the location for the high pavement design temperature at a

depth 20mm below the pavement surface and the low pavement design temperature at

the pavement surface, as studied by McGennis et al. (1995). Therefore using the

following empirical equations 4.1 and 4.2 recommended by Asphalt Institute in

Superpave manual series no. 1 and 2, air temperatures could be converted into the

maximum and minimum pavement design temperatures. (Superpave Manual Series

No. 1 & 2)

78.17)9545.0()2.422289.0200618.0(20max −×++−== LatLatairTmmTT .. (4.1)

Where

T20mm = high pavement design temperature at a depth of 20 mm, 0C

Tair = seven-day average high air temperature, 0C

Lat = the geographical latitude of the project in degrees.

CairTT °+= 7.1859.0min……………………………..……………………….. (4.2)

Where

Tmin = minimum asphalt pavement temperature below surface, 0C

Tair = minimum air temperature, 0C

4.1 Collection of Air Temperature Data across Pakistan

Temperature data of following 30 stations as listed in Table 4.1 was collected from

Pakistan Metrological Office, Karachi from year 1987 to 2006. The location of each

station has been shown on Pakistan map in Figure 4.1.

49

Table 4.1: Location of Weather Stations across Pakistan

Description of Weather Stations

Sr. No. Station Sr. No. Station

1 Dalbandin 16 Chitral

2 Hyderabad 17 Dera Ismail Khan

3 Jacobabad 18 Dir

4 Karachi 19 Faisalabad

5 Lassbella 20 Gilgit

6 Nawabshah 21 Islamabad

7 Nokkundi 22 Khanpur

8 Pasni 23 Kotli

9 Quetta 24 Lahore

10 Rohri 25 Multan

11 Sibbi 26 Murree

12 Zhob 27 Muzaffarabad

13 Astor 28 Parachinar

14 Bahawalpur 29 Peshawar

15 Balakot 30 Sialkot

50

Figure 4.1: Location Map of Weather Stations

4.2 Analysis of Air Temperature Data

Contrary to the previous grading systems, the Superpave binder specification is

theoretically based on performance rather than on empirical relationships between

basic physical properties and observed performance. Performance graded binders

were selected based on the climate in which the pavement would serve.

The distinction among the various binder grades is the specified minimum and

maximum temperatures at which the requirements must be met as given in Table B1

at Annexure B formulated by McGennis et al. (1995).

51

For example a binder classified as a PG 58-34 means that it will meet the high

temperature physical property requirements up to a temperature of 58˚C and the low

temperature physical property requirements down to - 34˚C. For a particular area the

high and low temperatures grades would extend as far as necessary in the standard

six-degree increments as stated by McGennis et al. (1995).

Maximum and minimum air temperatures were identified as shown in Table 4.3,

using the standard procedure as described by McGennis et al. (1995). Maximum and

minimum pavement design temperatures were calculated using the standard equations

4.1 and 4.2. Station wise precise performance grades were developed using statistical

analysis with 98% reliability. The performance Grades for the 30 stations were

established as given at Annex A. A typical data for one station (Islamabad) has been

presented in Tables 4.2, 4.2a and 4.2b. Further, using these performance grades, the

whole country was divided into four zones.

52

Table 4.2: Air Temperature Data for Islamabad

Station Islamabad

Daily Maximum Daily Minimum

Sr.No. Year Temperature (˚C) Month Temperature (˚C) Month

1 1987 39.00 July 2.90 Jan

2 1988 38.60 June 4.60 Dec

3 1989 38.90 June 2.50 Jan

4 1990 39.50 June 4.90 Dec

5 1991 37.90 June 2.90 Jan

6 1992 38.40 June 5.20 Jan

7 1993 38.10 June 3.00 Jan

8 1994 40.10 June 4.40 Jan

9 1995 40.70 June 2.40 Jan

10 1996 36.00 June 1.20 Dec

11 1997 36.30 June 2.10 Jan

12 1998 38.70 June 3.20 Dec

13 1999 39.10 June 3.60 Dec

14 2000 39.90 June 4.00 Jan

15 2001 34.40 May 2.10 Jan

16 2002 39.00 June 3.00 Jan

17 2003 39.40 June 1.80 Jan

18 2004 36.70 June 5.10 Jan

19 2005 39.90 June 2.00 Dec

20 2006 37.80 June 3.80 Jan

Table 4.2a: Maximum Pavement Temperature for Islamabad

Maximum Pavement Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78

T20mm Maximum Pavement Temperature @ Depth of 20 mm from the top of Pavement 61.15

T air Seven Days Average Maximum air Temperature in °C 39.800

Lat The Geographical Latitude of Project in Degrees 33°-43' 33.72 Table 4.2b: Minimum Pavement Temperature for Islamabad

Minimum Pavement Temperature

Tpav = 0.859 Tair +1.7˚C

Tpav Minimum Pavement Temperature 2.73

Tair Minimum Air Temperature 1.20

53

4.3 Zoning of Pakistan on the Basis of Pavement Temperatures

Summary of the complete data for 30 stations has been presented as station wise

performance grading at Annexure B (Table B2). Different performance grading zones

identified on 30 stations have been summarized in Table 4.3 and shown in Figure 4.2.

Table 4.3: Summary of Zoning

Zone No. of stations in the Zone Performance Grade

Zone-1 6 PG 76-4

Zone-2 13 PG 70-4

Zone-3 5 PG 64-4

Zone-4 2 PG 58-10

Zone-5 1 PG 70-10

Zone-6 2 PG 64-10

Zone-7 1 PG 58-4

54

Figure 4.2: Zoning Map

55

Chapter Five

56

Chapter 5

Material Characterization

5.0 Introduction

Mineral aggregate, filler, binder and air constitute asphaltic concrete. Depending upon the

aggregate gradation and the proportions of the constituents, a wide range of asphalt mixtures

can be produced. The strength of a typical continuously graded mixture depends upon the

aggregate interlocking structure and the lubrication for compaction is generally provided by

the binder which also serves to glue the mixture together. On the other hand, strength of a

typical gap-graded mixture depends on the coarse aggregate skeleton bound by a

bitumen/filler “mortar” since it poses a discontinuous aggregate gradation. Irrespective of the

mixture type, the overall material performance depends upon the micro mechanical behavior

of aggregate particles, binder and air voids.

5.1 Aggregate Properties

The permanent deformation of the pavement structure is greatly dependent upon aggregate

properties whereas low temperature cracking and fatigue cracking is less dependent.

According to the Asphalt Institute Superpave Series No. 2, in the Superpave system, there are

two categories of aggregate properties that are used; these are consensus properties and

source properties.

5.1.1 Consensus Aggregate Properties

Aggregate properties which are critical to well performing HMA are called Consensus

Properties because there is a wide agreement in their use and specified values. These

properties are based on the criterion of traffic level and position within the pavement

structure. Materials closer to the pavement surface requires strict consensus properties as

these are subjected to high traffic levels. The criterion must not be applied to individual

57

component but is intended to be applied to proposed aggregate blend. The consensus

aggregate properties are:

• Coarse Aggregate Angularity

• Fine Aggregate Angularity

• Flat and Elongated Particles

• Clay Content (Sand Equivalent)

The detailed description of these properties is given below:

5.1.1.1 Coarse Aggregate Angularity

Asphalt Institute’s Superpave Series No. 2 defines the coarse aggregate angularity as “The

percentage by mass of the aggregates larger than 4.75 mm with one or more fractured faces”.

High shear strength for rutting resistance and a high degree of internal friction can be

achieved by specifying this property. The standard test method specified by Superpave Mix

Design Technology for Coarse Aggregate Angularity is ASTM D5821, “Test Method for

determining the Percentage of Fractured Faces in Coarse Aggregate”. The required minimum

values for coarse aggregate as a function of traffic level and position within the pavement are

presented in Table 5.1(reproduced from Asphalt Institute’s Superpave Series No. 2)

Table 5.1: Superpave Aggregate Consensus Property Requirements

Coarse Aggregate Angularity (Percent),

minimum

Uncompacted Void Content of Fine

Aggregate (Percent), minimum

Design ESALs

(million) ≤ 100 mm > 100 mm ≤ 100 mm > 100 mm

Sand Equivalent (Percent), minimum

Flat and Elongated (Percent), maximum

< 0.3 55/- -/- - - 40 - 0.3 to < 3 75/- 50/- 40 40 40 10 3 to < 10 85/80 60/- 45 40 45 10 10 to < 30 95/90 80/75 45 40 45 10

≥ 30 100/100 100/100 45 45 50 10

58

5.1.1.2 Fine Aggregate Angularity

Asphalt Institute’s Superpave Series No. 2 defines the fine aggregate angularity as “The

percent air voids present in loosely compacted aggregates smaller than 2.36 mm”. Fractured

faces are indicated by the void content. Greater the void content more will be the fractured

faces. High degree of internal friction and high shear strength for rutting resistance can be

achieved by specifying this property. Particle shape, surface texture and grading influence

fine aggregate angularity. AASHTO T304 (Uncompacted Void Content of Fine Aggregate) is

the test method specified by the Superpave.

Fine, washed and dried aggregate sample is poured through a standard funnel into a small

calibrated cylinder as shown in Figure 5.1 (reproduced from Asphalt Institute’s Superpave

Series No. 2). The mass of the fine aggregate in the filled cylinder of known volume is

measured and from the difference between the cylinder volume and fine aggregate volume

collected in the cylinder, the void content can be determined. The fine aggregate volume is

calculated using the fine aggregate bulk specific gravity (Gsb)

The minimum values required for fine aggregates angularity as a function of traffic level and

position within the pavement are presented in Table 5.1.

Figure 5.1: Fine Aggregate angularity apparatus

59

5.1.1.3 Flat and Elongated Particles

Asphalt Institute’s Superpave Series No. 2 defines the flat and elongated particles as “The

percentage by mass of coarse aggregates that have a maximum to minimum dimension ratio

greater than five “These particles have the tendency to break down during construction and

under traffic so these are undesirable. ASTM D4791 (Flat or Elongated Particles in Coarse

Aggregates) is the test procedure used. The test is limited to coarse aggregates larger than

4.75 mm.

A proportional caliper device as shown in Figure 5.2 (reproduced from Asphalt Institute’s

Superpave Series No. 1) is used for the measurement of the dimensional ratio of a

representative sample of aggregate particles. Aggregate particle with its largest dimension is

placed between the swinging arm and the fixed post at position A as shown in Figure 5.2.

When the aggregate is placed between the swinging arm and fixed post at position B, the

swinging arm remains stationary. Aggregates that are unable to fill this gap are counted as

flat or elongated particle.

Table 5.1 presents the required maximum values for flat and elongated particles in coarse

aggregates.

Figure 5.2: Measuring flat and elongated particles

60

5.1.1.4 Clay Content (Sand Equivalent)

Asphalt Institute’s Superpave Series No. 2 defines the clay content as “clay content is the

percentage of the clay material contained in the aggregate fraction that is finer than a 4.75

mm sieve” .AASHTO T176 (Plastic Fines in Graded Aggregate and Soils by Use of the Sand

Equivalent Test) ASTM D2419 is the test procedure for the measurement of the clay content.

Fine aggregate and a flocculating solution are mixed in a graduated cylinder and are agitated

in order to loose the clay fines present in and coating the aggregates. The clayey material is

held into suspension above the granular aggregates by the flocculating solution. After the

settlement of the granular aggregates, the settled sand and the cylinder height of the

suspended clay is measured as shown in Figure 5.3 (reproduced from Asphalt Institute’s

Superpave Series No. 2). The ratio of the sand to clay height expressed as a percentage gives

the sand equivalent value. Table 5.1 gives the allowable clay content values for the fine

aggregates.

Figure 5.3: Sand Equivalent Test Apparatus

61

The consensus aggregate properties and their comparison with the Superpave recommended

values are shown in Table 5.2:

Table 5.2: Aggregate Consensus Properties

Sr. No.

Aggregate Consensus Properties Test Results (Percent)

Criteria (Asphalt Institute)

(%) 1 Coarse Aggregate Angularity 70 55-100 2 Fine Aggregate Angularity 42 40-45 3 Sand Equivalent 72 40-50 4 Flat and Elongated 4.75 10(Max)

5.1.2 Source Aggregate Properties

The aggregate properties whose critical values are source specific are often used by the

agencies to classify local sources of aggregates. The properties may be used as a source

acceptance control and are relevant during the mix design process. The source aggregate

properties are:

• Toughness

• Soundness

• Deleterious Materials

The description of each of these properties is as under:

5.1.2.1 Toughness

Asphalt Institute’s Superpave Series No. 2 defines the toughness as “toughness is the percent

loss of material from an aggregate blend during the Los Angeles Abrasion Test (AASHTO

T96 or ASTM C131 or C535)”. The toughness property test estimates the coarse aggregate

resistance to abrasion and mechanical degradation that occurs during handling, construction

and service. To perform the test, coarse aggregates larger than 2.36 mm are subjected to

impact and grinding by steel spheres. Due to this mechanical degradation, the mass

percentage of the coarse material lost gives the toughness. Typically the maximum loss

62

values range from 35 – 45 percent.

5.1.2.2 Soundness

According to Asphalt Institute’s Superpave Series No. 2, soundness is defined as “The

percent loss of material from an aggregate blend during the sodium or magnesium sulfate

soundness test (AASHTO T104 or ASTM C88)”. The resistance of aggregate to in-service

deterioration is determined by using this test. The test is applicable to both coarse and fine

aggregates.

An aggregate sample is subjected to repeated immersions in saturated sodium or magnesium

sulfate solution followed by oven drying. Salts precipitate in the permeable void space of the

aggregate during the drying period and rehydrates upon re-immersion with internal expansive

forces similar to the expansive forces of the freezing water. This cycle constituting one

immersion and drying is called soundness cycle. The total percent loss for the required

number of cycles over various sieve intervals gives the soundness. Typical values for the

maximum loss range from 10 to 20 percent for five cycles.

5.1.2.3 Deleterious Materials

Asphalt Institute’s Superpave Series No. 2 defines the deleterious materials as “Deleterious

materials are defined as the mass percentage of contaminants such as clay lumps, shale,

wood, mica, and coal in the blended aggregates (AASHTO T112 or ASTM C142)”. The test

is applicable to both coarse and fine aggregates.

A wet sieving aggregate size fraction over the specified sieves is done and the percentage by

mass of the material lost as a result of it gives the percent of the clay lumps and the friable

particles. Maximum allowable percentage of these materials ranges from as low as 0.2

percent to as high as 10 percent and depends upon the exact composition of the contaminant.

The source aggregate properties and their comparison with the Superpave recommended

values are shown in Table 5.3:

63

Table 5.3: Aggregate Source Properties

Sr. No. Aggregate Source Properties Test Results (%)

Criteria (Asphalt Institute)

(%) 1 Soundness 3.25 10-20

2 Toughness 36 35-45

3 Deleterious materials 1 0.2-10

5.2 Aggregate Gradation

Asphalt Institute’s Superpave Series No. 2 specifies the gradation by modifying an approach

already used by some agencies. Permissible gradation is defined by the 0.45 power gradation

chart. To show the cumulative particle size distribution of an aggregate blend, the 0.45 power

chart uses a unique graphing technique. The chart is between the percent passing and sieve

size in millimeters raise to the 0.45 power with percent passing as ordinate and arithmetic

scale of sieve size in millimeters as abscissa.

Maximum density gradation is an important feature of the 0.45 power chart. The maximum

density line represents a gradation where aggregate particles fit together in their closest

possible arrangement and gives a straight line relationship between sieve size, raised to 0.45

power and percent passing from the maximum aggregate size to the origin.

Superpave defines the maximum and nominal maximum size, as the maximum size is “one

sieve larger than the nominal maximum size” and the nominal maximum sieve size as “one

sieve size larger than the first sieve to retain more than 10 percent”.

The Superpave Gradation Limits are shown in Figure 5.4 (reproduced from Asphalt

Institute’s Superpave Series No. 2)

Two additional features; Control point and Restricted Zone have been added to the 0.45

power chart to specify aggregate gradation as reported by McGennis et al (1995)

64

Figure 5.4: Superpave Gradation Limits

5.2.1 Control Points

According to Anderson et al. (1995), the function of the control points is to act as master

ranges through which gradations must pass. These are placed at the smallest size (0.075 mm),

intermediate size (2.36 mm) and at the nominal maximum size. The limits of these points

vary with the nominal maximum aggregate size of the design mixture.

5.2.2 Restricted Zone

According to McGennis et al. (1995), along the maximum density gradation between the

intermediate size (either 4.75 mm or 2.36 mm) and the 0.3 mm size, the restricted zone

resides. It is generally recommended that the gradation should not pass through the band

formed by the restricted zone. Gradations are called humped gradations when they pass

through the restricted zone from below the zone because of the characteristic hump in the

grading curve.

According to Kennedy et al. (1995), a mixture containing too much fine sand in comparison

with the total sand or an over-sanded mixture represents a humped gradation resulting in

tender mix behavior, evident by compaction problems during construction. Moreover, the

65

resistance to the permanent deformation (rutting) is reduced by using these mixtures.

According to Solaimanian et al. (1995), gradations following the maximum density line in

the fine aggregate sieves are prevented by the restricted zone as these gradations have

inadequate VMA to allow space for sufficient asphalt for durability. With minor variations in

the asphalt content these gradations can easily become plastic.

Gradations passing below the restricted zone are recommended by Superpave but it is not a

requirement; gradations passing above the restricted zone may be used successfully. Some of

the gradations passing through the restricted zone perform satisfactorily and before using

them, experience or testing is evaluated to determine if the aggregate performs satisfactorily.

Asphalt Institute use the term “Design Aggregate Structure” to describe the aggregate

particle size distribution. Superpave gradations require that the design aggregate structure

resides between the control points.

Table 5.4 (reproduced from Asphalt Institute’s Superpave Series No. 2) provides the five

mixture gradations by their nominal maximum aggregate size defined by Superpave. Table

5.5 (reproduced from Asphalt Institute’s Superpave Series No. 2) gives the Superpave

aggregate gradation control points and Table 5.6 (reproduced from Asphalt Institute’s

Superpave Series No. 2) introduces the Boundaries of Aggregate restricted zone.

Table 5.4: Superpave Mixture Gradations

Superpave Designation Nominal Maximum Size (mm)

Maximum Size (mm)

37.5 mm 37.5 50.0 25.0 mm 25.0 37.5 19.0 mm 19.0 25.0 12.5 mm 12.5 19.0 9.5 mm 9.5 12.5

66

Table 5.5: Superpave Aggregate Gradation Control Points

Nominal Maximum Aggregate Size – Control Points ( Percent Passing)

37.5 mm 25.0 mm 19.0 mm 12.5 mm 9.5 mm Sieve Size (mm)

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

50.0 100 37.5 90 100 100 25.0 90 90 100 100 19.0 90 90 100 100 12.5 90 90 100 100 9.5 90 90 100 4.75 90 2.36 15 41 19 45 23 49 28 58 32 67 0.075 0 6 1 7 2 8 2 10 2 10

Table 5.6: Boundaries of Aggregate Restricted Zone

Minimum and Maximum Boundaries of Sieve Size for Nominal Maximum Aggregate Size ( Minimum and Maximum Percent Passing)

37.5 mm 25.0 mm 19.0 mm 12.5 mm 9.5 mm

Sieve Size

within Restricted

Zone (mm)

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

0.300 10.0 10.0 11.4 11.4 13.7 13.7 15.5 15.5 18.7 18.7 0.600 11.7 15.7 13.6 17.6 16.7 20.7 19.1 23.1 23.5 27.5 1.18 15.5 21.5 18.1 24.1 22.3 28.3 25.6 31.6 31.6 37.6 2.36 23.3 27.3 26.8 30.8 34.6 34.6 39.1 39.1 47.2 47.2 4.75 34.7 34.7 39.5 39.5 - - - - - -

Table 5.7 and Figure 5.4 show the aggregate gradations adopted for the research work.

Whereas Table 5.8 shows the mix design characteristics of the three mixes.

67

Table 5.7: Design Aggregate Gradations

Sieve Size (mm)

Trial Blend Superpave

(% Passing)

Trial Blend Marshall

(% Passing)

Trial Blend SMA

(% Passing) 37.5 100 100 100 25 100 100 100 19 95 95 100

12.5 80 82 95 9.5 63 66 65 4.75 43 44 28 2.36 29 30 20 0.075 5 4 10

0

20

40

60

80

100

120

0.01 0.1 1 10 100

Seive Diameter (mm)

%ag

e P

assin

g

SUPERPAVE MARSHALL SMA

Figure 5.5: Design Aggregate Gradations for three Mixes

68

Table 5.8: Mix Design Characteristics of Three Mixes

Sr. No.

Mix characteristics Marshall (Dense Graded Mix)

SMA (Gap Graded Mix)

Superpave (Dense Graded Mix)

1 Binder grade 60-70 60-70 PG 64-22 2 Binder content (%) 4.3 6 4 3 Compacting machine Marshall

Hammer Marshall Hammer

Gyratory Compactor

4 Aggregate gradation NHA Class A Wearing Course

Gap Graded Superpave Criteria

5 Vma 15.58% 17% 13.5% 6 Air voids 6.3% 4% 4.12% 7 Type of additives Nill Cellulose fibre

(Interfibe Road-Cel™Nill

8 Amount of additive Nill 0.3% Nill 9 Original Specimen

Size 4 inch 4inch 6 inch

5.3 Binder Testing

Conventional binder properties and their comparison with the AASHTO M 20 specifications

are shown in Table 5.9 below:

Table 5.9: Physical Properties of Asphalt

Test Test Result Criteria G*/sin δ @ 64 0C (Fresh) kPa 1.939 1.0 minimum G*/sin δ @ 64 0C (RTFO) kPa 4.356 2.2 minimum Flash point(0C) 300 230 0C minimum Penetration 63 60-70 Specific Gravity at 25 0C 1.02 1.01-1.06 Ductility at 25 0C 114 100 minimum Softening point(0C) 50 48-56

Performance based binder testing in collaboration with Attock Oil Refinery Rawalpindi

(ARL) was performed using the procedures recommended by Asphalt institute (SP-1)

Manual. Binder testing was performed on both the neat (60/70 Grade) asphalt and polymer

modified bitumen (1.6% Elvaloy 4160).

69

The results are tabulated in Annexure C (Tables C1 and C2).Summary of the results is given

in Table 5.10 and 5.11.

Table 5.10: Summary of Performance based Binder Properties of 60/70 Grade Bitumen

SHRP PERFORMANCE GRADE ANALYSIS

Sample: PAKISTAN BASE, ATTOCK 60/70 PEN, NEAT

Precise SHRP Grade PG 62.6 – 24.5

Table 5.11: Summary of Performance based Binder Properties of Polymer

Modified Bitumen (1.6 % Elvaloy) Results.


Sample: 01-102A - Pakistan Attock 60 - 70 Pen 1.6% 4170, 0.7% SPA, Overnight cook,

1600C

Precise SHRP Grade PG 78.6 – 23.3

70

Chapter Six

71

Chapter 6

Performance Based Testing

6.0 Introduction One of the essential aspects regarding asphalt mix or pavement design and evaluation

procedure is material testing. In order to understand the behavior of materials in service, it is

important to study their different properties subjected to various parameters. To evaluate the

performance of materials a general procedure which is conventionally followed includes the

following steps;

• Determination of factors affecting properties of the materials.

• Selection of the testing equipment and procedures that simulates field conditions.

• Selection of the material design properties which correlate with the design procedures.

Flexible pavements involve bound and unbound material testing. Performance based testing

to predict rutting in asphaltic wearing course mix is the focus of this research. The over all

purpose of this chapter is to present comprehensive performance based testing of asphaltic

concrete samples using Superpave, Marshall and Stone Mastic asphalt (SMA) mixes.

Following tests were performed to evaluate the comparative performance of asphalt mixes;

• Indirect Tensile Modulus Test

• Uniaxial Loading Strain Test (Creep Test)

• Dynamic Modulus Test

• Wheel Tracking Test

Each test has been described with sample preparation, testing conditions, test procedure, test

results in tabular and graphical form.

72

6.1 Indirect Tensile Modulus Test

This test was performed according to ASTM D4123 using UTM – 5P (Universal Testing

Machine – 5 Pulses). The five pulse indirect tensile modulus test is actually a material

stiffness test in which a pulsed diametric loading force is applied to a specimen diametrically

and the resulting total recoverable diametric strain is then measured at axes 90˚ from the

applied force.

A value of 0.4 for Poisson’s ratio is used as constant. For controlled temperature testing, the

specimen’s skin and core temperatures were estimated by transducers inserted in a dummy

specimen and located near the specimen under testing. The specimens were mounted in the

indirect test jigs as per procedure described by the manual (Manual UTM-5P) and the results

were stored in the computer data base. Specimens were tested at test pulse period of 1000ms,

pulse width of 400ms and peak loading force of 500N.

The test conditions are shown in Table 6.1 below:

Table 6.1: Testing Conditions for Indirect Tensile Modulus Test

Mix Type

Temperature(0C)

Indirect Tensile Modulus Test

25

40

Marshall

SMA

Superpave

55

Test Pulse Period=1000ms

Pulse Width=400ms

Peak Loading Force=500N

The results obtained for different mixes are shown in Table 6.2 below:

73

Table 6.2: Resilient Modulus for Marshall, Superpave and SMA at Different Temperatures

Resilient Modulus (Mpa) Temperature (°C)

Marshall Superpave SMA

25 5053 8000 2673

40 908 2000 734

55 242 550 296

The results obtained for different mixes are graphically shown in Figure 6.1 below;

10

100

1000

10000

25 40 55TEMPERATURE (oC)

RES

ILIE

NT

MO

DU

LUS

(Mpa

)

Marshall SuperPave SMA

Figure 6.1: Comparison of Resilient Modulus between Marshall, Superpave and SMA at Different Temperatures

74

6.2 Uniaxial Loading Strain Test (Creep Test):

This test was performed by using UTM – 5P (Universal Testing Machine – 5 Pulses). The

machine has the capability to apply uniaxial repeated loadings of different magnitudes and at

different temperatures. Uniaxial strain test initially applies a static conditioning stress to the

specimen and measures the resulting accumulated strain. The magnitude and applied time

duration of the conditioning stress were set to 10 KN/m2 and conditioning time as 100

seconds. The loading pulse period of 2000ms (2 sec) and pulse width of 500 ms (0.5 sec) was

taken. The specimen was subjected to repeated pulse loading of 3600 cycles at stress levels

of 100, 300 and 500 KN/m2 and at temperature of 25°C, 40°C and 55°C. As pulse loading

continued, the accumulated strain was measured using two Linear Variable Displacement

Transducers (LVDTs) during both the conditioning and pulsed loading stages of the test and

displayed as a plot with linear scale axis. For each test, the temperature inside the testing

cabin was brought to the desired value before the commencement of the test. The specimen

to be tested was kept inside the temperature controlled chamber for approximately two hours

before the start of test in order to achieve a uniform temperature. The conditioning time of

two hours was found to be sufficient by measuring the temperature within a dummy core

specimen. Specimen set inside the UTM – 5P chamber is shown in Figure 6.2.

Figure 6.2: Creep Testing using UTM-5P

75

The results obtained from the creep test are shown graphically in Figures 6.3 through 6.5. It was

found that accumulated strains (%) increased with the increase in temperature and number of

cycles. At low temperatures amount of accumulated strains (%) were lower for all the mixes than

that at higher temperatures. Superpave mixes behaved better than the Marshall and SMA mixes

during creep test in terms of low accumulated strains (%) even at higher temperatures. SMA

performed better as compared to the Marshall Mix. Testing conditions are shown in Table 6.3

Table 6.3: Uniaxial Loading Strain Test Conditions

Creep Testing Parameters

No. of Pulses = 3600 Pulse Period = 2000ms = 2 sec Pulse Width = Loading Time = 500ms = 0.5 sec Rest Period = 1.5 sec

Mix Type

Temperature(°C)

Stress Level (Kpa) 100 300

25

500 100 300

40

500 100 300

Marshall

SMA

Superpave

55

500

Following different results obtained from the above test are given below:

• Resilient strain

• Accumulated Strain

• Resilient Modulus

• Creep Stiffness

Results obtained from the creep test have been summarized at Annexure D (Table D1).also

they have been discussed one by one in the preceding section.

76

Resilient Strains (%) obtained at specified testing conditions for the three mixes have been

presented in the Table 6.4 below:

Table 6.4: Uniaxial Loading Strain Test Results Showing Resilient Strain (%)

Resilient Strain (%)

Mix Type

Superpave SMA Marshall Stress Level

Temperature (°C)

Individual Average Individual Average Individual Average

25 0.016 0.011 0.015

0.014 0.017 0.026 0.035

0.026

0.0057 0.0247 0.024

0.019

40 0.019 0.038 0.024

0.027 0.04 0.02 0.037

0.033 0.0355 0.0322 0.0348

0.034 100KPa

55 0.022 0.038 0.033

0.031 0.031 0.071 0.075

0.059 0.0333 0.0103 0.0734

0.039

25 0.032 0.037 0.039

0.036 0.025 0.048 0.064

0.046 0.05 0.039 0.04

0.043

40 0.053 0.064 0.060

0.059 0.11 0.11 0.07

0.097 0.055 0.065 0.081

0.067 300Kpa

55 0.08 0.11 0.11

0.1 0.08 0.13 0.12

0.11 0.14 0.16 0.09

0.13

25 0.03 0.05 0.04

0.04 0.11 0.064 0.116

0.097 0.05 0.03 0.055

0.045

40 0.073 0.079 0.061

0.071 0.077 0.19 0.053

0.107 0.09 0.02 0.13

0.08 500Kpa

55 0.092 0.124 0.114

0.11 0.15 0.136 0.083

0.123

0.11 0.16 0.15

0.14

77

The above results are being graphically presented at different temperatures and stress levels

in Figures 6.3 through 6.8.

0

0.02

0.04

0.06

0.08

0.1

0.12

0 100 200 300 400 500 600

STRESS LEVEL (kPa)

RES

ILIE

NT

STR

AIN

(%)

S PAVE SMA MARSHALL

Figure 6.3: Relationship between Resilient Strain and Stress at 25°C for 3 mixes

0

0.02

0.04

0.06

0.08

0.1

0.12

0 100 200 300 400 500 600

STRESS LEVEL (kPa)

RES

ILIE

NT

STR

AIN

(%)

S PAVE SMA MARSHALL

78

Figure 6.4: Relationship between Resilient Strain and Stress at 40°C for 3 mixes.

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 100 200 300 400 500 600

STRESS LEVEL (kPa)

RES

ILIE

NT

STR

AIN

(%)

S PAVE SMA MARSHALL

Figure 6.5: Relationship between Resilient Strain and Stress at 55°C for 3 mixes.

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

20 30 40 50 60

TEMPERTAURE (0C)

RES

ILIE

NT

STR

AIN

(%)

S PAVE SMA MARSHALL

Figure 6.6: Relationship between Resilient Strain and Temperature at 100 KPa for 3 mixes.

79

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

20 30 40 50 60

TEMPERATURE (0C)

RES

ILIE

NT

STR

AIN

(%)

S PAVE SMA MARSHALL


0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

20 30 40 50 60

TEMPERATURE (0C)

RES

ILIE

NT

STR

AIN

(%)

S PAVE SMA MARSHALL


80

Accumulated Strain (%) obtained from the Uniaxial Loading Strain Test at different test

conditions are shown in Table 6.5 below:

Table 6.5: Uniaxial Loading Strain Test Results showing Accumulated Strain (%)

Accumulated Strain (%)

Mix Type

Super Pave SMA Marshal

Stress Level

Temperature (°C)


25 0.1415 0.1625 0.1502

0.15 0.30 0.25 0.52

0.36 0.0552 0.25 0.52

0.39

40 0.1451 0.4235 0.2757

0.28 0.45 0.35 0.55

0.45 0.88 0.99 0.67

0.85 100KPa

55 0.40 0.36 0.38

0.38 0.45 0.65 0.61

0.57 1.35 0.44 0.42

1.35

25 0.39 0.22 0.32

0.31 0.5 0.8 1.0

0.77 0.41 0.56 0.54

0.5

40 0.15 0.40 0.50

0.35 1.29 1.74 1.45

1.5 1.23 1.13 1.07

1.14 300KPa

55 0.45 0.5 0.46

0.47 5.9 4.9 2.7

4.5 1.78 2.16 2.59

2.18

25 0.14 0.52 0.33

0.33 1.00 0.91 1.30

1.07 0.56 1.67 0.76

1.0

40 0.39 0.48 0.45

0.44 2.67 3.72 4.16

3.5 2.55 2.96 3.69

3.05 500KPa

55 0.82 0.76 0.52

0.70 5.7 3.8 4.0

4.5 5.61 2.52 2.07

4.4

81

The above results are being presented graphically in Figures 6.9 through 6.23.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA

Figure 6.9: Relationship between Accumulated Strain and Pulse Count at 100 KPa and 25°C

0

0.5

1

1.5

2

2.5

3

3.5

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA


82

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 200 400 600 800 1000

PULSE COUNT

ACCU

MU

LATE

D S

TRAI

N(%

)

S PAVE SMA MARSHALL


83

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL


0

0.5

1

1.5

2

2.5

0 200 400 600 800 1000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA

Figure 6.14: Relationship between Accumulated Strain and Pulse Count

at 300 KPa and 55°C

84

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA

Figure 6.15: Relationship between Accumulated Strain and Pulse Count At 500 KPa and 25°C

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA


85

0

1

2

3

4

5

6

0 1000 2000 3000 4000

PULSE COUNT

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE MARSHALL SMA


0

0.2

0.4

0.6

0.8

1

1.2

0 100 200 300 400 500 600

STRESS LEVEL(KPa)

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL

Figure 6.18: Relationship between Accumulated Strain and Stress Level at 25°C

86

0

0.5

1

1.5

2

2.5

3

3.5

4

0 100 200 300 400 500 600

STRESS LEVEL(KPa)

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL


0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 100 200 300 400 500 600

STRESS LEVEL(KPa)

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL


87

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

20 30 40 50 60

TEMPERATURE (0C)

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL

Figure 6.21: Relationship between Accumulated Strain and Temperature at 100 kPa

0

0.5

1

1.5

2

2.5

3

20 30 40 50 60

TEMPERATURE (0C)

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL


88

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

20 30 40 50 60

TEMPERATURE (0C)

AC

CU

MU

LATE

D S

TRA

IN(%

)

S PAVE SMA MARSHALL


89

Resilient Modulus obtained from different mixes at different test conditions is shown in Table 6.6 below:

Table 6.6: Uniaxial Loading Strain Test Results Showing Resilient Modulus Resilient Modulus (MPa)

Mix Type

Super Pave SMA Marshal

Stress Level

Temperature

(°C)


25 705 760 737

734 300 255 154

278 416 404 1756

410

40 359 412 423

398 268 501 256

262 286 286 314

300 100KPa

55 650 573 604

609 109 94 97

100 137 306 986

137

25 742 684 716

714 1213 620 461

440 336 497 597

673

40 599 587 545

577 272 262 417

317 624 695 699

477 300KPa

55 543 501 507

517 107 92 101

100 258 280 208

249

25 749 723 730

734 454 780 428

554 545 503 515

521

40 567 560 541

556 645 261 944

453 379 1477 576

477 500KPa

55 539 502 510

517 104 91 105

100 343 327 320

330

90

The results are graphically presented in Figures (6.24 – 6.29)

0

200

400

600

800

1000

1200

1400

0 100 200 300 400 500 600

STRESS LEVEL (KPa)

RES

ILIE

NT

MO

DU

LUS

(MPa

)

S PAVE SMA MARSHALL

Figure 6.24: Relationship between Resilient Modulus and Stress 25°C

0

200

400

600

800

1000

1200

1400

0 100 200 300 400 500 600

STRESS LEVEL (KPa)

RES

ILIE

NT

MO

DU

LUS

(MPa

)

S PAVE SMA MARSHALL

Figure 6.25: Relationship between Resilient Modulus and Stress Level at 40°C

91

0

200

400

600

800

1000

1200

1400

0 100 200 300 400 500 600

STRESS LEVEL (KPa)

RES

ILIE

NT

MO

DU

LUS

(MPa

)

S PAVE SMA MARSHALL

Figure 6.26: Relationship between Resilient Modulus and Stress Level at 55°C

0

100

200

300

400

500

600

700

800

20 30 40 50 60

TEMPERATURE (0C)

RES

ILIE

NT

MO

DU

LUS

(MPa

)

S PAVE SMA MARSHALL

Figure 6.27: Relationship between Resilient Modulus and Temperature at 100 kPa

92

0

100

200

300

400

500

600

700

800

20 30 40 50 60

TEMPERATURE (0C)

RES

ILIE

NT

MO

DU

LUS

(MPa

)

S PAVE SMA MARSHALL


0

100

200

300

400

500

600

700

800

20 25 30 35 40 45 50 55 60

TEMPERATURE (0C)

RES

ILIE

NT

MO

DU

LUS

(MPa

)

S PAVE SMA MARSHALL


Creep Stiffness obtained from different mixes at different test conditions is shown in Table 6.7 below:

93

Table 6.7: Uniaxial Loading Strain Test Results Showing Creep Stiffness

Creep Stiffness (MPa)

Mix Type

Superpave SMA Marshall Stress Level

Temperature (°C)


25 71 60 70

67 34 39 19

31 180 40

19.4 30

40 68 23 47

46 22 29 18

23 11 11 15

15 100KPa

55 25 59 42

42 21 15 18

18 7.42 23 25

12

25 167 85 84

112 59 37 28

41 71 53 55

60

40 75 69 72

72 23 17 20

20 24 26 27

26 300KPa

55 55 50 54

53 11 9 10

10 16 14 11

14

25 86 73 90

83 49 54 38

47 89 30 65

62

40 72 79 77

76 18 13 12

14 19 11 13

14 500KPa

55 63 72 75

70 15 10 14

13 8.84 20 24

14

94

The results are graphically presented in Figures 6.30 through 6.35.

0

20

40

60

80

100

120

0 100 200 300 400 500 600

STRESS LEVEL (KPa)

CR

EEP

STIF

FNES

S (%

)

S PAVE SMA MARSHALL

Figure 6.30: Relationship between Creep Stiffness and Stress Level at 25˚C

0

20

40

60

80

100

120

0 100 200 300 400 500 600

STRESS LEVEL (KPa)

CR

EEP

STIF

FNES

S (%

)

S PAVE SMA MARSHALL


95

0

20

40

60

80

100

120

0 100 200 300 400 500 600

STRESS LEVEL (KPa)

CR

EEP

STIF

FNES

S (%

)

S PAVE SMA MARSHALL


0

10

20

30

40

50

60

70

80

20 30 40 50 60

TEMPERATURE (0C)

CR

EEP

STIF

FNES

S (%

)

S PAVE SMA MARSHALL

Figure 6.33: Relationship between Creep Stiffness and Temperature at 100 KPa

96

0

10

20

30

40

50

60

70

80

20 30 40 50 60

TEMPERATURE (0C)

CR

EEP

STIF

FNES

S (%

)

S PAVE SMA MARSHALL


0

10

20

30

40

50

60

70

80

20 30 40 50 60

TEMPERATURE (0C)

CR

EEP

STIF

FNES

S (%

)

S PAVE SMA MARSHALL


97

6.3 Dynamic Modulus Testing: Dynamic modulus testing is used to accurately characterize the strength and load resistance

of asphalt mixes. Dynamic modulus of asphalt is a viscoelastic test response developed under

sinusoidal loading conditions. It is the absolute value of dividing the peak-to-peak stress by

the peak-to-peak strain for a material subjected to a sinusoidal loading. Dynamic modulus

test was performed according to AASHTO TP 62-4 test method using NU – 14 machine on

asphalt cylindrical specimens of 4 x 6 inch size at three temperatures and nine different stress

levels. For Superpave mix, samples of 4” diameter were extracted from original 6” samples

as shown in Figure 6.36 below:

Figure 6.36: Extracted Sample for Dynamic Modulus Testing From 6” Dia. Original Gyratory Sample

The machine is capable of applying dynamic loading of different magnitudes and frequencies

at different temperature conditions. Strains were measured using gauges affixed at fixed

positions on the test specimens as shown in Figure 6.37, and the data was automatically fed

into a computer to calculate the test results.

98

Figure 6.37: Dynamic Modulus Testing Arrangement using NU-14

The conditions during test are described in Table 6.8 below:

Table 6.8: Dynamic Modulus Test Conditions

Dynamic Modulus Test

No. of Cycles=200

Frequencies(Hz)=25,10,5,1,0.5,0.1 Mix Type Temperature(0C)

Stress Level(Kpa) 300 500 25 700 150 200 40 250 35 50

Marshall SMA

Superpave

55 65

The results in summarized form are given at Annexure D (Tables D2, D3 and D3)

99

The results obtained are shown in Tables 6.9 – 6.11

Table 6.9: Comparison of Dynamic Modulus Results for Marshall, SMA and Superpave Mix at 25°C

Dynamic Modulus (MPa) at 25°C MARSHALL SMA SUPERPAVE Frequency

(Hz) 300 kPa

500 kPa

700 kPa

300 kPa

500 kPa

700 kPa

300 kPa

500 kPa

700 kPa

25 7000 7631 7360 5558 7223 7066 7700 11649 8942 10 4901 5700 5773 3981 5076 5137 6294 9238 7048 5 3961 4424 4463 3239 4087 4149 5070 7843 5884 1 2259 2550 2752 1919 2338 2567 3316 5249 3833

0.5 1784 1977 2254 1469 1842 2116 2592 4420 3192 0.1 1104 1179 1474 867 1081 1358 1647 2800 2080



(Hz) 150 kPa

200 kPa

250 kPa

150 kPa

200 kPa

250 kPa

150 kPa

200 kPa

250 kPa

25 2654 3450 2556 7066 3832 1703 8942 5077 5145

10 1876 2367 1846 5137 2474 1216 7048 3871 3698

5 1502 1854 1449 4149 2032 994 5883 2927 2883

1 931 1132 950 2570 1134 643 3833 1680 1665

0.5 794 938 829 2116 898 469 3192 1341 1344

0.1 586 665 628 1358 542 454 2080 850 889



(Hz) 35 kPa

50 kPa

65 kPa

35 kPa

50 kPa

65 kPa

35 kPa

50 kPa

65 kPa

25 379 421 435 427 464 485 735 742 737 10 299 327 346 341 372 396 558 549 571 5 273 296 310 315 340 361 479 484 493 1 229 247 261 260 286 303 357 373 386

0.5 205 227 246 240 269 289 323 337 351 0.1 180 199 220 223 254 212 264 286 305

100

The results are presented graphically in figures 6.38 through 6.46

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL

Figure 6.38: Relationship between Dynamic Modulus and No. of Cycles for Marshall, SMA, Superpave Mix at 300 kPa and 25°C

0

2000

4000

6000

8000

10000

12000

14000

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL


101

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL


0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL


102

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S (M

Pa)

SP SMA MARSHALL


0

500

1000

1500

2000

2500

3000

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL


103

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL


0

100

200

300

400

500

600

700

800

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL


104

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250

NO. OF CYCLES

DYN

AM

IC M

OD

ULU

S(M

Pa)

SP SMA MARSHALL

Figure 6.46: Relationship between Dynamic Modulus and No. of Cycles for Marshall, SMA, Superpave Mix at 65 Kpa and 55°C

The Permanent Strain obtained from the Dynamic Modulus Test are shown in Tables 6.12 through 6.14

Table 6.12: Comparison of Permanent Strain Results for Marshall, SMA and Superpave Mix

at 25°C

Permanent Strain at 25°C

MARSHALL SMA SUPERPAVE Frequency

(Hz) 300 kPa

(10-4)

500 kPa

(10-4)

700 kPa

(10-4)

300 kPa

(10-4)

500 kPa

(10-4)

700 kPa

(10-4)

300 kPa

(10-4)

500 kPa

(10-4)

700 kPa

(10-4)

25 5.6 9.11 6.13 12.48 8.51 8.54 2.27 1.78 4.35 10 7 15.68 11.38 18.57 13.14 13.74 4.32 3.03 6.58 5 7.7 19.82 15 22.9 16.65 17.21 5.6 4.56 7.7 1 8.7 26.55 20.09 30.73 23.26 23.5 7.75 7.57 9.5

0.5 9 28.88 21.79 33.49 25.77 25.87 8.49 8.52 10.09 0.1 9.8 35.3 26.23 41.94 33.32 32.67 9.52 10.86 11.88

105

Table 6.13: Comparison of Permanent Strain Results for Marshall, SMA and Superpave Mix at 40°C



(Hz) 150 kPa

(10-4)

200 kPa

(10-4)

250 kPa

(10-4)

150 kPa

(10-4)

200 kPa

(10-4)

250 kPa

(10-4)

150 kPa

(10-4)

200 kPa

10-4)

250 kPa

(10-4)

25 4.27 4.31 5.95 31.96 9.25 69.54 3.88 4.1 4.35

10 4.58 4.75 6.87 39.35 11.24 87.69 4.45 4.59 4.77

5 4.73 5.01 7.44 43.53 12.49 96.53 4.66 4.83 4.99

1 4.89 5.19 8.09 47.96 13.34 104.87 4.75 5.06 5.21

0.5 5.01 5.31 8.28 49.01 13.49 106.61 4.86 5.14 5.32

0.1 5.18 5.42 8.84 50.69 13.61 109.35 5.03 5.27 5.47

Table 6.14: Comparison of Permanent Strain Results for Marshall, SMA and Superpave Mix at 55°C



(Hz) 35 kPa

(10-4)

50 kPa

(10-4)

65 kPa

(10-4)

35 kPa

(10-4)

50 kPa

(10-4)

65 kPa

(10-4)

35 kPa

(10-4)

50 kPa

(10-4)

65 kPa

(10-4)

25 19.74 7.84 7.09 16.31 5.91 6.2 2.27 2.31 2.94

10 22.87 9.52 8.39 18.51 6.21 6.91 2.49 2.37 2.99

5 24.44 10.5 9.19 19.33 6.34 7.11 2.61 2.41 3.03

1 26.45 11.75 9.96 19.96 6.45 7.23 2.74 2.46 3.12

0.5 27.07 12.16 10.19 20.06 6.57 7.36 2.77 2.53 3.25

0.1 28.74 13.28 10.59 20.93 6.73 7.5 3 2.67 3.37

106

The results are presented graphically in Figures 6.47 through 6.55

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0.004

0.0045

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL

Figure 6.47: Relationship between Permanent Strain and No. of Cycles for Marshall, SMA, Superpave Mix at 300 kPa and 25°C

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0.004

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


107

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


0.00038

0.00043

0.00048

0.00053

0.00058

0.00063

0.00068

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


108

0.00038

0.00058

0.00078

0.00098

0.00118

0.00138

0.00158

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


0.0002

0.0022

0.0042

0.0062

0.0082

0.0102

0.0122

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


109

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


110

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0 50 100 150 200 250

NO. OF CYCLES

PER

MA

NEN

T ST

RA

IN

SP SMA MARSHALL


6.4 Wheel Tracking Test This test was performed according to EN 12697-22 test method using Wheel Tracking

Device. The susceptibility of bituminous material to rut under wheel load is determined using

the wheel tracking test. Specimens prepared in laboratory or cut from the real pavement can

be tested for rutting due to repeated passes of a loaded wheel at different temperatures.

The apparatus consists of a loaded wheel which passes repeatedly over the sample held

securely on a table and an attached device monitors the rate at which rut develops at the

specimen surface. Temperature control device is required so that the temperature of the test

specimen during testing remains uniform and maintained constant at ± 1 °C. Test specimens

were prepared in the laboratory using Roller Compactor as shown in Figure 6.56.

111

Figure 6.56: Roller Compactor Viewed from End

This process of compaction involved four stages. In the first stage, the specimen was

compacted under 2 bars pressure with 10 number of passes. In the second stage, the specimen

was further compacted under 5 bars of pressure with 10 number of passes. In stage 3, the

specimen was compacted under 4 bars of pressure with 5 number of passes and in final stage

4; the specimen was compacted under 3 bars of pressure with 5 number of passes. Size of the

specimen used was 305mm X 305mm X 50mm.

Table 6.15 shows the test conditions.

Table 6.15: Wheel Tracking Test Conditions

Mix Type

Temperature(0C)

Wheel Tracking Test

25

40

Marshall

SMA

Superpave 55

No. of Passes = 10,000

112

First of all specimens were conditioned at a specified temperature. After the placement of the

compacted specimen in the wheel tracking machine, the loaded wheel was brought in contact

with the specimen and the rut development was monitored with an automatic displacement

measuring device. Wheel Tracking Machine with specimen under load wheel is shown in

Figure 6.57.

Figure 6.57: Loaded wheel in contact with the specimen

Specified temperature of the specimen and the chamber were maintained at 25˚C, 40˚C and

55˚C during the test. The displacement measuring device automatically transferred the

measured rut depth at increments of 100 cycles to the attached computer. The tracking

continued for 10,000 cycles or for a period when the specified rut depth was achieved. Final

condition of the specimen at the end of the test is shown in Figure 6.58.

Figure 6.58: Specimen showing rutting after completion of the test

113

The results obtained from Wheel Track Test in terms of Rut Depth (mm) obtained at

different temperatures have been tabulated in the following tables (Table 6.16 – 6.21)

Table 6.16: Relationship between No. of Passes and Rut Depth for SMA

Rut Depth at Specified Temperature (mm)

No. of Passes 25˚C 40˚C 55˚C

0 0 0 0

1000 0.3 1.56 1.29

2000 0.37 1.95 2.19

3000 0.52 2.21 2.52

4000 0.69 2.39 3.26

5000 0.82 2.65 3.85

6000 0.94 2.79 4.32

7000 0.99 2.88 4.87

8000 1.14 3.01 5.3

9000 1.12 3.47 5.88

10000 1.29 3.6 5.98

Table 6.17: Relationship between No. of Passes and Rut Depth for Marshall

Rut Depth at Specified Temperature (mm) No. of Passes

25˚C 40˚C 55˚C

0 0 0 0

1000 0.7 0.56 1.15

2000 0.96 0.94 2.4

3000 1.27 1.42 4.03

4000 1.53 1.91 5.7

5000 1.79 2.42 7.5

6000 2.01 3.11 9.1

7000 2.2 3.39 10.37

8000 2.43 3.76 12.5

9000 2.63 3.95 15.35

10000 2.82 4.18 17.15

114

Table 6.18: Relationship between No. of Passes and Rut Depth for Superpave

Rut Depth at Specified Temperature (mm) No. of Passes

25˚C 40˚C 55˚C

0 0 0 0

1000 0.03 0.78 1.15

2000 0.39 1.48 2.4

3000 0.67 2.2 3.5

4000 0.88 2.88 4.7

5000 1.11 3.62 5.8

6000 1.28 4.15 6.6

7000 1.46 4.78 7.3

8000 1.71 5.36 8.2

9000 1.92 5.88 9.34

10000 2.15 6.4 10.1

Table 6.19: Comparison of Rut Depth (mm) between SMA, Marshall and Superpave Mix at 25˚C

Rut Depth at 25˚C For Different Mixes No. of Passes

SMA Marshall Superpave

0 0 0 0

1000 0.3 0.7 0.15

2000 0.37 0.96 0.39

3000 0.52 1.27 0.67

4000 0.69 1.53 0.88

5000 0.82 1.79 1.11

6000 0.94 2.01 1.28

7000 0.99 2.2 1.46

8000 1.06 2.43 1.71

9000 1.12 2.63 1.92

10000 1.29 2.82 2.15

115


Rut Depth at 40˚C For Different Mixes

No. of Passes SMA Marshall Superpave

0 0 0 0 1000 1 0.56 0.78 2000 1.7 0.94 1.48 3000 2.21 1.42 2.2 4000 2.39 1.91 2.88 5000 2.65 2.42 3.62 6000 2.79 3.11 4.15 7000 2.95 3.39 4.78 8000 3.25 3.76 5.36 9000 3.47 3.95 5.88 10000 3.6 4.18 6.4


Rut Depth at 55˚C For Different Mixes No. of Passes

SMA Marshall Superpave

0 0 0 0

1000 1.29 1.15 1.15

2000 2.19 2.4 2.4

3000 2.5 4.03 3.5

4000 3.26 5.7 4.7

5000 3.85 7.5 5.8

6000 4.32 9.1 6.6

7000 4.87 10.37 7.3

8000 5.3 12.5 8.2

9000 5.88 15.35 9.34

10000 6.15 17.15 10.1

116

Results in summarized form are shown in Table 6.22 indicating the final rut depth (mm).

Table 6.22: Summary of Wheel Tracking Test Results for Three Mixes

Rut Depth (mm)

Temperature SMA

Marshall

Superpave

25˚C

1.2

2.82 2.15

40˚C

3.6

6.4 4.18

55˚C

6.15

17.15 10.1

Graphical presentation of the rut depth data has been shown in Figures 6.59 through 6.64.

0

1

2

3

4

5

6

7

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

NO. OF PASSES

RU

T D

EPTH

(mm

)

25˚C 40˚C 55˚C

Figure 6.59: Relationship between No. of Passes and Rut Depth for SMA Mix at different Temperatures

117

0

2

4

6

8

10

12

14

16

18

20

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

NO. OF PASSES

RU

T D

EPTH

(mm

)

25˚C 40˚C 55˚C

Figure 6.60: Relationship between No. of Passes and Rut Depth for Marshall Mix at different

Temperatures

0

2

4

6

8

10

12

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

NO. OF PASSES

RU

T D

EPTH

(mm

)

25˚C 40˚C 55˚C

Figure 6.61: Relationship between No. of Passes and Rut Depth for Superpave Mix at

different Temperatures

118

0

0.5

1

1.5

2

2.5

3

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

NO. OF PASSES

RU

T D

EPTH

(mm

)

SMA MARSHALL SUPERPAVE

Figure 6.62: Comparison of SMA, Marshall and Superpave at 25°C

0

1

2

3

4

5

6

7

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

NO. OF PASSES

RU

T D

EPTH

(mm

)



119

0

2

4

6

8

10

12

14

16

18

20

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

NO. OF PASSES

RU

T D

EPTH

(mm

)



120

Chapter Seven

121

Chapter 7

Discussion

7.0 Introduction The objective of this study was to compare the design of asphaltic concrete by Superpave,

Marshall and Stone Mastic Asphalt mix methods for typical asphaltic concrete mixes used in

Pakistan. They were subjected to a comprehensive laboratory testing after samples of mixes

were prepared at the design asphalt contents and aggregate gradations. A comprehensive

laboratory based performance testing of these mixes was carried out at different

temperatures, stress levels and loading frequencies in order to compare their relative

properties which influence asphalt rutting and performance. The previous chapters explained

in detail different aspects of this research work.

7.1 Volumetric Study of Different Mixes In case of Superpave Mix samples, specific gravity (Gmb) of the asphalt mix increased by

about 3.1% and 1.9% as compared to Marshall and SMA samples respectively. This could be

due to better compaction achieved through the kneading action of Superpave Gyratory

Compactor. Superpave samples had 35% less air voids (Va) than Marshall samples which

indicate higher percentage of air voids than that required at optimum asphalt content. SMA

and Superpave Mix had almost same air voids content. The higher percentage of air voids

results in a more permeable mix allowing air and water to pass through easily and may result

in premature and brittle failure of the mix.

Voids in Mineral Aggregates (VMA) in Superpave samples were less than Marshall and

SMA samples by about 13.3% and 20.6% respectively which show increased density and

reduced air voids. Voids Filled with Asphalt (VFA) in Superpave samples were more than

Marshall and SMA samples by 16.8% and 9% respectively. Excessive VFA value can

produce inadequate space for asphalt expansion, loss of aggregate to aggregate contact,

rutting and shoving in high traffic areas. Similarly lesser VFA value can result in loss of

122

bond and consequently loss of mix stability. Superpave Method provided significant

improvement in the Volumetric Properties of the mix.

7.2 Performance Based Properties

7.2.1 Modulus of Resilience (Mr)

An essential input for the flexible pavement design, the Modulus of resilience (Mr) generally

relates the load spreading ability of materials and indicates their load associated deformation

characteristics. It varies with temperature and loading frequencies due to the visco-elastic

properties of asphalt. In the present study, samples of Superpave (6” Dia), Marshall (4”Dia)

and SMA (4”Dia) were tested according to Standard Test Method for Indirect Tension Test

for Resilient Modulus of Bituminous Mixtures (ASTM D 4123-82) using UTM-5P

(Universal Testing Machine).

The graphical relationships between Modulus of resilience (Mr) and temperature have shown

that Mr decreased with the increase in temperature. It also exhibits that Superpave mixes

showed maximum values of Mr at all temperatures than the other two mixes.

After the critical analysis of the results for all mixes, it can be generalized that Mr decreases

with the increase in temperature. The Mr of Marshall mix decreased from 5053(Mpa) at 250C

to 908 (Mpa) at 400C and 242 (Mpa) at 550C. The Mr of Superpave mix decreased from

8000(Mpa) at 250C to 2000 (Mpa) at 400C and 550 (Mpa) at 550C. The Mr of Stone Mastic

Asphalt (SMA) decreased from 2673(Mpa) at 250C to 1650 (Mpa) at 400C and 296 (Mpa) at

550C. A rapid decrease in Mr Value is evident during temperature shift from 250C to

400C.Superpave mix performed better as compared to the other two mixes. Even at 400C Mr

for Superpave is sufficient enough. Load carrying capacity of asphalt decreases with the

increase in temperatures.

7.2.2 Repeated Uniaxial Loading Strain Test Properties

Repeated Uniaxial Loading Strain test was performed in order to study the rutting behaviour

123

of different asphalt mixes. Following parameters were studied for this test:

• Accumulated Strain (%) • Creep Stiffness • Resilient Strain • Resilient Modulus

7.2.2.1 Accumulated Strain (%)

Results for accumulated strain by Superpave, SMA and Marshall Methods reveal that

Superpave samples gave much lower values as compared to the SMA and Marshall Method.

The accumulated strain values of Superpave samples were 160% and 135% lower than SMA

and Marshall Methods at 25˚C respectively. Whereas the Accumulated Strains resulting from

Superpave samples were 379% and 354% lower than SMA and Marshall Methods at 40˚C.

Even at 55˚C the Superpave samples induced accumulated strains were 483% and 382%

lower than SMA and Marshall Methods.

Accumulated strain (%) plotted against the number of load cycles showed that it increased

with the increase in loading pulses and increase in temperature at different stress levels of

100,300 and 500 kPa. The trend was almost the same under different temperatures and stress

levels. Superpave mixes induced minimum accumulated strains while Marshall and SMA

induced maximum.

A shift of asphalt behaviour was observed in case of SMA as shown in Figure 6.21-6.23.

Accumulated strain (%) abruptly increased when stress level was increased from 100 kPa to

300 kPa and 500 kPa. This could be due to the fact that the SMA samples were not confined

when tested for repeated uniaxial loading strain test .Consequently at higher stress levels

,mix showed high accumulated strain.

It reflected that permanent deformation increases with the increase in load repetitions

creating ruts. Also the effect of high temperatures in summer on rutting is clear from the

aforementioned results. The improved volumetric properties of Superpave mixes resulted in

excellent performance in terms of lowest induced accumulated even at extreme temperatures

and stress levels. As compaction method of Superpave mixes simulates the field compaction,

124

therefore Superpave mix design can be used efficiently to solve the critical problems in

asphalt especially the permanent deformation.

7.2.2.2 Creep Stiffness

Creep Stiffness or stiffness modulus (Ec) can be explained using equation 7.1.

Ec=Stress Applied/Accumulated Axial Strain=σ/ξc……………………………….(7.1)

Kamal and Niazi (2007) also studied the effect of different asphalt mixes on rutting and

stiffness and concluded that stiffness of mixture is enhanced to resist loads. Stiffness is the

ratio of uni-axial stress and resulting strain. The resulting strain depends upon temperature

and loading time due to the visco-elastic nature of Asphalt. At low temperatures and short

loading times, the material behaves like an elastic material. Under these circumstances the

mixture stiffness depends on binder and VMA (Voids in Mineral Aggregates) which is called

elastic stiffness. At higher temperatures and longer loading times, the stiffness is called

viscous stiffness and depends on the type, grading, shape and texture of aggregates and the

method of compaction and VMA of the mix.

After comparing the results of Marshall, Superpave and SMA Mixes, it was evident that the

Creep Stiffness of Superpave mix is much greater than SMA and Marshall mixes. The values

of Superpave mix were 244% greater than SMA and 81% greater than Marshall Mix at 25˚C.

The values of creep stiffness for Superpave Mix were 267% greater than SMA and 275%

greater than Marshall Mix at 40˚C. The values of creep stiffness for Superpave Mix were

333% greater than SMA and 309% greater than Marshall Mixes at 55˚C.

7.2.2.3 Resilient Strain

The values of resilient strain for Superpave mix are 85% smaller than SMA Mix and 23%

smaller than Marshall Mix at 25˚C. The values of Superpave mix are 45% smaller than SMA

samples and 17% smaller than Marshall Samples at 40˚C. The values of Superpave samples

are 37% smaller than SMA samples and 27% smaller than Marshall Samples at 55˚C.

125

Lesser values of resilient strain indicate more stable mix.

7.2.2.4 Resilient Modulus

Resilient modulus (Mr) can be explained using equation 7.2.

Mr = Stress Applied/Resilient Axial Strain = σ/ξr…………………………………….(7.2)

The values of Superpave in this case were 86% and 22% greater than SMA and Marshall

Mixes respectively at 25˚C. The values of Superpave mix were 52% greater than SMA and

23% greater than Marshall Mixes at 40˚C. The values of Superpave Mix were 447% greater

than SMA and 169% greater than Marshall Mixes at 55˚C.

7.2.3 Dynamic Modulus

Zhou et al. (2003) reported that the distinction between resilient modulus test and the

dynamic modulus test is that the first one applies loading of any waveform with a specified

rest period while the second one applies a sinusoidal or haversine loading with no rest period

as shown in Figure 7.1 (reproduced from pavement guide for Washington state department of

transportation (WSDOT)). They also concluded from their research study that complex

modulus is one of the techniques to elucidate the visco elastic property of asphalt mix, which

is a complex quantity whose real part presents the elastic stiffness and the imaginary part

shows the internal damping of asphalt mix. The absolute value of the complex modulus is

generally stated as the dynamic modulus. Dynamic modulus test is a candidate for Superpave

Simple Performance Test Development and one of the essential inputs for flexible pavement

design using 2002 Design Guide.

Dynamic Complex Modulus testing was performed on different samples of the three mixes

based on wide range of temperatures (250C, 400C, 550C) and frequencies (25Hz, 10 Hz, 5 Hz,

1 Hz, 0.1 Hz, 0.01 Hz).

126

Figure 7.1: Effect of Stress and Resulting Accumulated Strain at the End of Test

After comparing the numeric values of dynamic modulus it was found that dynamic modulus

at 25˚C for Superpave mix was greater than the SMA Mix by 72% and was greater than the

Marshall Mix by 53%. Dynamic modulus at 40˚C for Superpave mix was greater than the

SMA Mix by 87% and greater than the Marshall results by 135%. Dynamic modulus at 55˚C

for Superpave mix was greater than the SMA mix by 40% and greater than the Marshall

results by 60%.

7.2.3.1 Permanent Strains

Kandhal et al. (2003) studied the potential of dynamic creep to predict rutting and found that

dynamic creep was capable of quantifying the aggregate and gradation type on rutting

potentials of asphalt mixes.

The values of dynamic permanent strain (creep) for Superpave mix samples were 245%

smaller than SMA Mix samples and 150% smaller than Marshall Mix samples at 25˚C. The

values of dynamic permanent strain (creep) for Superpave mix samples were 930% smaller

than SMA Mix samples and 19% smaller than Marshall Mix samples at 40˚C. The values of

dynamic permanent strain (creep) for Superpave mix samples were 300% smaller than SMA

Mix samples and 457% smaller than Marshall Mix samples at 55˚C.

127

Low dynamic permanent strain (creep) values indicate less rutting susceptibility where as

higher values indicate high rutting susceptibility.

7.2.4 Rut Depth

In wheel tracking test, the rut depth (mm) is measured with respect to the number of passes.

More rut depth indicates poor mix performance and the less rut depth indicates excellent mix

performance. The results indicate that the rut depths of Superpave mix were 79% greater

than SMA and 31% less than Marshall at 25˚C. The results indicate that the rut depths of

Superpave mix were 16% greater than SMA and 53% less than Marshall at 40˚C. The results

indicate that the rut depths of Superpave mix were 64% greater than SMA and 69% less than

Marshall at 55˚C.

Stone mastic asphalt (SMA) performed best during wheel track test showing minimum rut

depths even at the high temperatures. At 550C, a totally different behavior of asphalt was

observed. Marshall mix failed before completing the total number of passes (10,000). An

abrupt change in rut depth was observed during shifting of temperature from 400C to 550C.

The performance of Superpave Mix was better as compared to Marshall Mix during Wheel

Track Test.

The above performance indicates that the better performance of SMA could be due to the gap

graded aggregate structure of SMA and formation of a stone to stone aggregate skeleton.

7.3 Master Curves Development

Master curves were developed using dynamic modulus values determined at multiple

temperatures and loading frequencies to account for temperature and rate of loading effects

on the modulus of asphalt concrete. The Mechanistic-Empirical Pavement Design Guide uses

a modulus determined from master curve. Master curves were developed using the principle

of time-temperature superposition. First a standard reference temperature was selected, which

was 40°C for present study. After that measured dynamic modulus data at various

128

temperatures were shifted with respect to loading frequency until the curves combine into a

single smooth curve. The master curve of dynamic modulus as a function of frequency

explains the loading rate dependency of the material. The amount of shifting at each

temperature required to form the master curve describes the temperature dependency of the

material.

Three types of master curves are developed which are described as follows:

1. Master Curve for Superpave Mix at different temperatures(25°C, 40°C, 55°C) and

frequencies(25Hz,10Hz,5Hz,1Hz,0.5Hz,0.1Hz), shown in Figure 7.2.

2. Master Curve for Marshall Mix at different temperatures(25°C, 40°C, 55°C) and

frequencies(25Hz,10Hz,5Hz,1Hz,0.5Hz,0.1Hz), shown in Figure 7.2

3. Master Curve for SMA Mix at different temperatures(25°C, 40°C, 55°C) and

frequencies(25Hz,10Hz,5Hz,1Hz,0.5Hz,0.1Hz), shown in Figure 7.4

Figure 7.2 Master Curve for Superpave Mix

129

Figure 7.3 Master Curve for Marshall Mix

Figure 7.4: Master Curve for SMA Mix

130

Chapter Eight

131

Chapter 8

Conclusions, Recommendations and Research Potential

8.1 Conclusions The aim of present research work was to check whether Superpave mix design method using

indigenous materials, under local traffic loading conditions and prevailing temperature

regime has superiority over the conventional mixes with respect to rutting or not. Basically

two dense graded and one gap graded mix was studied. Dense graded mixes were prepared

using Superpave and Marshall Mix Design approaches while gap graded mix (Stone Mastic

Asphalt) was prepared using Marshall Mix Design Method. Nominal maximum aggregate

size for dense graded mixes was 12.5 mm whereas it was 9.5 mm for gap graded mix. All of

the mixes were prepared at optimum asphalt contents. Size of Superpave and Marshal Mix

samples was 6 inch (Dia.) *6 inch (Height) and 4 inch (Dia.) *2 ½ inch (Height) respectively.

The main conclusions drawn from the current research work are being presented in this

chapter. Recommendations offered by the present research work have the potential to

stimulate researchers for further study which will open new vistas of knowledge for

technology.

1. Superpave mix showed better performance in terms of low accumulated strains (%)

(Permanent deformation) as compared to Marshall and SMA mixes which is an indication

of highly rut resistant mix. Accumulated strains increased with the increase in number of

load repetitions, stress level and temperature but percent increase in accumulated strains

(%) was more in the case of Marshall and SMA mixes to that of Superpave. It reflects

that under conditions of heavy traffic loadings and high temperatures, Superpave mix can

be a better option against rutting.

132

2. When accumulated strain (%) data was plotted against number of loading pulses, it was

noted that the shape of curve became flat for Superpave mixes after some initial strain

accumulation and continued with the same trend up to 3600 pulses, whereas for other two

mixes the curve trend kept on increasing up to the end of test. It indicates that permanent

deformation phenomenon continues throughout the performance life of Marshall and

SMA mixes whereas Superpave mix is capable of resisting permanent deformation after

some initial compaction.

3. Superpave mix showed in better performance in terms of low resilient strains (%), high

resilient modulus and high creep stiffness as compared to Marshall and SMA mixes.

4. During Indirect Tensile Modulus Testing, higher values of Modulus of Resilience (Mr)

were observed in case of Superpave mixes. Even at the maximum testing temperature

(55oC), Superpave mix performed better than the other two mixes.

5. Dynamic modulii of Superpave mix were also relatively higher at different dynamic

stress levels and temperatures as compared to SMA & Marshall. Permanent strain

induced revealed that Superpave mix behaved as a more stable mix in terms of lower

dynamic creep values .Dynamic creep increased with the increase in temperature for all

the mixes. It reflects that rutting is a function of dynamic loading and high temperature.

6. Aggregate gradation recommended by National Highways Authority (Class A Wearing

Course) falls well within the limits of Superpave gradation criteria. Aggregates used for

investigation satisfy both Superpave consensus and source properties requirements which

proved to be a good indication for implementation of Superpave locally.

133

7. Asphalt performance grades for Pakistan were formulated on the basis of comprehensive

air temperature data collection and analysis. It consisted of seven performance grades

namely, PG 76-4, PG 70-10, PG 70-4, PG 64-10, PG 64-4, PG 58-10 and PG 58-4.

Temperature zoning map was proposed to be implemented in Pakistan. The performance

grade of locally available 60/70 grade asphalt was found PG 64-28, which could be used

without any modification for zones 3(PG 64-4), 4(PG 58-10), 6(PG 64-10) and 7(PG 58-4).

For the hotter zones of the country, asphalt should be modified using polymer to achieve

PG 76-4, PG 70-4 and PG 70-10.

8. Rut depth increased with the increase in number of loaded wheel passes and temperature

for all mixes during Wheel Tracking Test .Stone Mastic Asphalt (SMA) performed better

against rutting as compared to the Superpave and Marshall mixes. Superpave mix was the

second least rutting susceptible mix during wheel tracking test. Marshall samples failed

during wheel tracking test before completing 10,000 wheel passes. At highest testing

temperature of 55oC, rut depth was 6.15 mm in the case of SMA. It could be due to the

confining provided to SMA mix during this test. SMA should be preferred in hot climatic

conditions.

9. Wheel tracking test can be referred as simple performance test for the comparison of

rutting resistance of various asphalt mixes.

10. SMA needs confinement for its proper study so Triaxial repeated loading and Triaxial

Dynamic Modulus testing should be preferred.

134

8.2 Recommendations 1. More HMA mixes (Polymer Modified Bitumen, CRMB etc.) should be evaluated

using Marshall and Superpave technologies.

2. While comparing with other mixes , SMA should be tested in confined conditions to

get better results

3. Full scale accelerated testing should be carried out to investigate the performance of

Superpave mixes in comparison with Marshall and SMA mixes.

4. Superpave technology should be adopted in Pakistan as a lot of infrastructure

development is still to be carried out.

5. Dynamic Modulus test should be used to simulate field rutting performance of hot

mix asphalt.

6. Dynamic Modulus Test should be used for rutting prediction in the laboratory using

its permanent deformation data.

7. Stone Mastic Asphalt should be evaluated thoroughly using other stabilizing agents

also.

8. Comprehensive guidelines should be developed for rut resistant asphalt mixes in

collaboration with NHA Pakistan.

9. Restrictions should be imposed on axle loads to avoid premature pavement failures.

135

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136

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145

ABBREVIATIONS AASHO American Association Of State Highway Officials AASHTO American Association Of State Highway And Transportation

Officials APA Asphalt Pavement Analyzer ARL Attock Oil Refinery Limited Rawalpindi ASTM American Society For Testing Materials BBR Bending Beam Rheometer DSR Dynamic Shear Rheometer DTT Direct Tension Tester FHWA Federal Highway Authority FRT French Road Tester Gmb Bulk Specific Gravity of Compacted Mixture Gmm Maximum Specific Gravity of Paving Mixture Gsb Aggregate Bulk Specific Gravity GTR Ground Tyre Rubber HMA Hot Mix Asphalt HWTD Hamburg Wheel-Tracking Device K-ATL Kansas Accelerated Testing Laboratory KDOT Kansas Department of Transportation Kpa Kilo Pascal Mpa Mega Pascal Mr Modulous Of Resilience NCHRP National Cooperative Highway Research Program NHA National Highway Authority Pakistan PAV Pressure Aging Vessel PG Performance Grade PMB Polymer Modified Bitumen PTI Pennsylvania Transport Institute RTFO Rolling Thin Film RV Rotational Viscometer SHRP Strategic Highway Research Program SMA Stone Mastic Asphalt SUPERPAVE Superior Performing Pavements USDOT United States Department of Transportation UTM-5P Universal Testing Machine -5 Pulse Va Air Voids VFA Voids Filled with Asphalt VMA Voids in Mineral Aggregates VMB Bulk Volume of Paving Mix VMM Void Less Volume of Paving Mix WSDOT Washington State Department of Transportation

146

Annexure A

147

Table A.1: Air Temperature Data for Dalbandin Station Dalbandin


Sr.No. Year Temperature (˚C) Month Temperature (˚C) Month

1 1987 42.30 August 1.8 Jan

2 1988 44.00 June 2.7 Jan

3 1989 42.60 June -0.80 Jan

4 1990 43.50 July 4.10 Dec

5 1991 43.50 July 3.90 Jan

6 1992 43.10 June 2.20 Jan

7 1993 42.80 July 2.30 Dec

8 1994 43.00 June 2.30 Dec

9 1995 42.50 July 1.30 Jan

10 1996 42.20 July 1.00 Dec

11 1997 44.00 July 2.60 Jan

12 1998 44.20 July 4.50 Jan

13 1999 43.60 July 1.90 Dec

14 2000 43.10 May 2.30 Jan

15 2001 48.50 May -0.70 Jan

16 2002 44.10 June

17 2003 43.60 June

18 2004 43.70 July 0.90 Dec

19 2005 45.00 July 0.60 Dec

20 2006 44.80 July -0.50 Jan

Table A.1a: Maximum Pavement Temperature for Dalbandin

Maximum Pavement Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 28°-54' 28.90

Table A.1b: Minimum Pavement Temperature for Dalbandin

Minimum Pavement Temperature

Tpav = 0.859 Tair +1.7˚C

Tpav Minimum Pavement temperature 1.01

Tair Minimum air temperature -0.80

148

Table A.2: Air Temperature Data for Hyderabad

Station Hyderabad


Sr.No. Year Temperature(˚C) Month Temperature(˚C) Month

1 1987 41.40 June 11.60 Jan

2 1988 42.90 May 12.80 Jan

3 1989 41.20 May 10.50 Jan

4 1990 40.20 May 13.20 Jan

5 1991 41.60 June 10.90 Jan

6 1992 41.50 May 11.60 Jan

7 1993 41.20 May 8.50 Dec

8 1994 42.10 May 11.60 Jan

9 1995 42.20 May 11.30 Jan

10 1996 41.10 May 12.00 Dec

11 1997 39.50 May 10.50 Jan

12 1998 41.50 May 11.80 Jan

13 1999 40.60 April 12.10 Jan

14 2000 40.60 April 11.60 Jan

15 2001 40.30 May 10.10 Jan

16 2002 42.60 May 10.70 Jan

17 2003 41.20 May 11.60 Jan

18 2004 41.70 May 11.40 Jan

19 2005 41.20 May 10.60 Jan

20 2006 41.80 May 10.30 Jan Table A.2a: Maximum Pavement Temperature for Hyderabad

Maximum Temperature

T20mm = [Tair -.00618 Lat2 + .2289 Lat + 42.2] x .9545 -17.78




Table A.2b: Minimum Pavement Temperature for Hyderabad

Minimum Temperature

Tpav = .859 Tair +1.7


Tair Minimum air temperature 8.50

149

Table A.3: Air Temperature Data for Jacobabad

Station Jacobabad Daily Maximum Daily Minimum


1 1987 44.50 June 6.40 Dec

2 1988 46.80 May 8.00 Jan

3 1989 43.40 June 7.00 Jan

4 1990 44.50 May 8.00 Dec

5 1991 46.20 June 7.10 Jan

6 1992 47.30 June 8.20 Jan

7 1993 45.60 May 7.90 Dec

8 1994 44.90 My 7.30 Jan

9 1995 45.50 June 9.10 Jan

10 1996 43.40 June 5.20 Dec

11 1997 41.70 June 5.90 Jan

12 1998 43.70 June 8.20 Dec

13 1999 44.00 May 8.30 Dec

14 2000 45.30 May 7.10 Jan

15 2001 45.20 May 6.60 Jan

16 2002 46.60 May 7.70 Jan

17 2003 46.00 June 8.50 Jan

18 2004 44.50 May 9.60 Jan

19 2005 44.70 June 7.10 Dec

20 2006 46.00 June 6.60 Jan

Table A.3a: Maximum Pavement Temperature for Jacobabad

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78


Tair Seven Days Average Maximum air Temperature in °C 46.357

Lat The Geographical Latitude of Project in Degrees 28°-17' 28.28 Table A.3b: Minimum Pavement Temperature for Jacobabad

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



150

Table A.4: Air Temperature Data for Karachi

Station Karachi



1 1987 36.30 October 9.40 Jan

2 1988 36.10 June 11.70 Jan

3 1989 36.40 May 10.60 Jan

4 1990 35.50 October 10.70 Dec

5 1991 36.40 October 9.00 Jan

6 1992 36.20 May 11.00 Jan

7 1993 36.50 October 12.50 Dec

8 1994 36.40 June 11.40 Jan

9 1995 36.90 May 11.40 Jan

10 1996 35.90 June 10.30 Jan

11 1997 34.50 June 11.20 Jan

12 1998 36.60 May 12.70 Jan

13 1999 36.70 October 12.40 Jan

14 2000 35.90 October 12.50 Jan

15 2001 36.00 October 11.50 Jan

16 2002 36.50 October 12.80 Jan

17 2003 37.00 October 12.00 Dec

18 2004 36.80 May 12.90 Jan

19 2005 36.10 June 12.30 Jan

20 2006 35.40 June 11.70 Jan

Table A.4a: Maximum Pavement Temperature for Karachi

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 24°-53' 24.88 Table A.4b: Minimum Pavement Temperature for Karachi

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



151

Table A.5: Air Temperature Data for Lassbella

Station Lassbella



1 1987 42.00 June 8.40 Dec

2 1988 42.90 June 10.30 Jan

3 1989 41.50 May 8.60 Jan

4 1990 41.20 May 9.90 Dec

5 1991 43.50 June 8.00 Jan

6 1992 42.90 June 8.90 Jan

7 1993 42.40 May 8.70 Dec

8 1994 42.70 June 8.30 Jan

9 1995 43.30 May 10.30 Jan

10 1996 40.90 June 8.80 Dec

11 1997 39.70 July 8.60 Jan

12 1998 42.20 June 9.90 Jan

13 1999 41.60 May 9.30 Jan

14 2000 41.00 June 8.10 Dec

15 2001 40.90 May 7.10 Jan

16 2002 42.90 May 7.70 Jan

17 2003 41.20 June 7.50 Dec

18 2004 42.60 May 7.90 Jan

19 2005 41.00 June 9.80 Jan

20 2006 42.50 June 8.60 Jan

Table A.5a: Maximum Pavement Temperature for Lassbella

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78




Table A.5b: Minimum Pavement Temperature for Lasbella

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



152

Table A.6: Air Temperature Data for Nawabshah

Station Nawabshah



1 1987 43.80 June 5.90 Dec

2 1988 45.80 May 7.70 Jan

3 1989 43.10 May 5.00 Jan

4 1990 44.20 May 8.50 Dec

5 1991 45.10 June 6.20 Jan

6 1992 46.20 June 7.50 Jan

7 1993 44.90 May 7.50 Dec

8 1994 45.10 May 7.30 Jan

9 1995 45.30 June 6.70 Jan

10 1996 43.10 June 4.80 Dec

11 1997 42.00 June 5.30 Jan

12 1998 44.70 June 7.10 Jan

13 1999 43.80 June 6.60 Jan

14 2000 45.10 June 5.60 Jan

15 2001 45.40 May 5.40 Jan

16 2002 47.80 May 6.40 Jan

17 2003 45.70 June 6.70 Jan

18 2004 45.10 May 7.50 Jan

19 2005 44.30 June 4.90 Jan

20 2006 46.40 May 4.50 Jan

Table A.6a: Maximum Pavement Temperature for Nawabshah

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 26°-15' 26.25 Table A.6b: Minimum Pavement Temperature for Nawabshah

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



153

Table A.7: Air Temperature Data for Nokkundi

Station Nokkundi



1 1987 43.00 August 4.80 Jan

2 1988 44.80 June 4.50 Jan

3 1989 44.40 June 1.20 Jan

4 1990 45.50 June 6.00 Dec

5 1991 44.00 July 5.30 Jan

6 1992 44.10 June 2.90 Jan

7 1993 43.50 June 3.40 Dec

8 1994 44.20 June 3.00 Jan

9 1995 42.40 July 4.40 Dec

10 1996 41.90 June 3.10 Dec

11 1997 44.50 July 3.80 Jan

12 1998 43.80 July 5.40 Jan

13 1999 43.60 June 4.00 Dec

14 2000 44.00 May 5.70 Jan

15 2001 43.40 July 3.00 Jan

16 2002 44.00 June 6.20 Jan

17 2003 43.30 June 5.50 Dec

18 2004 42.90 June 7.30 Dec

19 2005 44.00 July 5.40 Dec

20 2006 43.70 June 3.00 Jan

Table A.7a: Maximum Pavement Temperature for Nokkundi

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 28°-50' 28.83 Table A.7b: Minimum Pavement Temperature for Nokkundi

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



154

Table A.8: Air Temperature Data for Pasni

Station Pasni

Sr.No. Year Daily Maximum Daily Minimum Temperature(˚C) Month Temperature(˚C) Month

1 1987 37.20 May 10.30 Jan

2 1988 36.80 June 12.90 Dec

3 1989 37.00 May 11.00 Jan

4 1990 35.40 May 10.80 Dec

5 1991 36.40 June 11.40 Jan

6 1992 36.10 June 11.50 Jan

7 1993 38.00 May 13.40 Dec

8 1994 34.80 May 11.30 Jan

9 1995 35.90 May 12.80 Jan

10 1996 35.40 June 10.90 Jan

11 1997 34.60 June 11.40 Jan

12 1998 35.80 June 12.10 Dec

13 1999 35.50 October 11.90 Jan

14 2000 34.40 May 11.40 Jan

15 2001 35.00 October 10.30 Jan

16 2002 35.20 May 12.70 Jan

17 2003 35.80 June 12.90 Jan

18 2004 36.60 May 15.00 Dec

19 2005 35.20 June 13.30 Jan

20 2006 35.10 June 11.10 Jan

Table A.8a: Maximum Pavement Temperature for Pasni

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78




Table A.8b: Minimum Pavement Temperature for Pasni

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



155

Table A.9: Air Temperature Data for Quetta

Station Quetta



1 1987 35.50 July -3.50 Dec

2 1988 37.20 July -1.80 Jan

3 1989 35.3 June -4.00 Jan

4 1990 37.30 July -2.00 Dec

5 1991 37.10 July -1.10 Jan

6 1992 35.90 July -0.50 Jan

7 1993 35.60 July -3.20 Dec

8 1994 36.30 June -3.50 Jan

9 1995 36.20 July -2.40 Jan

10 1996 36.10 July -4.70 Dec

11 1997 37.80 July -2.90 Jan

12 1998 37.60 July -2.10 Dec

13 1999 37.00 July -1.50 Jan

14 2000 36.40 July -2.30 Jan

15 2001 37.40 July -5.00 Jan

16 2002 36.30 June -1.40 Jan

17 2003 35.70 July -2.60 Dec

18 2004 36.00 July -0.20 Dec

19 2005 37.60 July -4.30 Dec

20 2006 37.90 July 0.10 Dec

Table A.9a: Maximum Pavement Temperature for Quetta Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 30°-12' 30.20 Table A.9b: Minimum Pavement Temperature for Quetta

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C Tpav Minimum Pavement temperature -2.60 Tair Minimum air temperature -5.00

156

Table A.10: Air Temperature Data for Rohri

Station Rohri



1 1987 34.30 June 5.70 Jan

2 1988 44.00 June 8.10 Dec

3 1989 43.00 June 4.90 Jan

4 1990 43.00 May 6.10 Dec

5 1991 44.60 June 5.20 Jan

6 1992 44.90 June 8.90 Dec

7 1993 43.90 May 7.10 Jan

8 1994 43.70 May 7.10 Jan

9 1995 45.10 June 9.30 Jan

10 1996 42.50 June 7.50 Jan

11 1997 41.50 June 7.50 Jan

12 1998 43.60 May 6.80 Jan

13 1999 43.50 June 8.20 Dec

14 2000 44.40 May 8.10 Jan

15 2001 44.60 May 8.20 Jan

16 2002 45.90 May 8.50 Jan

17 2003 44.90 June 8.90 Jan

18 2004 44.50 June 9.50 Jan

19 2005 43.50 June 8.20 Dec

20 2006 44.90 May 8.70 Jan

Table A.10a: Maximum Pavement Temperature for Rohri

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 27°-41' 27.68 Table A.10b: Minimum Pavement Temperature for Rohri

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



157

Table A.11: Air Temperature Data for Sibbi

Station Sibbi



1 1987 45.30 June 5.0 Dec

2 1988 48.40 June 5.7 Jan

3 1989 44.00 June 4.70 Jan

4 1990 44.60 May

5 1991 46.20 June

6 1992 46.60 June

7 1993 44.80 May 8.1 Dec

8 1994 45.00 June 7.1 Jan

9 1995 46.50 June 6.1 Jan

10 1996 44.90 June 6.7 Dec

11 1997 41.70 June 6.7 Jan

12 1998 45.40 June 7.7 Jan

13 1999 45.80 June 6.5 Dec

14 2000 45.90 May 6.6 Jan

15 2001 46.40 May 5.0 Jan

16 2002 47.60 May 7.7 Jan

17 2003 46.70 June 7.2 Dec

18 2004 45.80 June 7.9 Jan

19 2005 45.00 June 5.4 Dec

20 2006 45.80 May 5.6 Jan

Table A.11a: Maximum Pavement Temperature for Sibbi

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 29°-33' 29.55 Table A.11b: Minimum Pavement Temperature for Sibbi

Minimum Temperature Tpav = 0.859 Tair +1.7˚C



158

Table A.12: Air Temperature Data for Zhob

Station Zhob



1 1987 37.50 July -1.20 Jan

2 1988 37.80 June 0.30 Dec

3 1989 35.30 June -3.70 Jan

4 1990 -1.60 Jan

5 1991 38.30 July 0.10 Jan

6 1992 36.90 June 1.20 Jan

7 1993 36.90 June -2.40 Jan

8 1994 37.50 June 2.50 Feb

9 1995 37.90 June -1.70 Dec

10 1996 37.60 June -6.50 Dec

11 1997 37.70 July -7.40 Jan

12 1998 35.60 June -0.10 Jan

13 1999 37.80 July 1.50 Jan

14 2000 36.70 July 1.00 Jan

15 2001 37.00 June 1.50 Jan

16 2002 38.00 July -0.80 Jan

17 2003 37.50 June 0.70 Dec

18 2004 38.10 July -1.90 Dec

19 2005 42.30 July -1.90 Jan

20 2006 38.00 July -1.90 Dec

Table A.12a: Maximum Pavement Temperature for Zhob

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 31°-21' 31.35 Table A.12b: Minimum Pavement Temperature for Zhob

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C

Tpav Minimum Pavement temperature -4.66


159

Table A.13: Air Temperature Data for Astor

Station Astor



1 1987 27.20 August -10.40 Jan

2 1988 27.40 July -4.90 Jan

3 1989 23.90 July -9.50 Jan

4 1990 28.50 July -4.10 Jan

5 1991 27.10 August -11.20 Jan

6 1992 27.10 August -5.30 Jan

7 1993 25.60 August -8.20 Jan

8 1994 28.90 August -5.00 Jan

9 1995 28.10 August -12.10 Jan

10 1996 26.70 August -9.50 Jan

11 1997 26.50 August -5.90 Jan

12 1998 28.30 July -6.70 Jan

13 1999 27.60 July -4.00 Jan

14 2000 26.40 July -7.00 Jan

15 2001 27.70 July -6.00 Jan

16 2002 27.70 August -12.00 Jan

17 2003 28.20 July -5.90 Dec

18 2004 26.10 July -5.80 Jan

19 2005 27.10 August -7.80 Jan

20 2006 29.30 July -6.40 Jan

Table A.13a: Maximum Pavement Temperature for Astor

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 35°-22' 35.37 Table A.13b: Minimum Pavement Temperature for Astor

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



160

Table A.14: Air Temperature Data for Bahawalpur

Station Bahawalpur


Sr.No. Year Temperature (˚C) Month Temperature(˚C) Month

1 1987 41.80 June 5.60 Dec

2 1988 43.90 May 7.00 Jan

3 1989 41.40 May 5.30 Jan

4 1990 41.90 May 7.20 Dec

5 1991 43.20 June 5.30 Jan

6 1992 44.50 June 6.20 Jan

7 1993 43.30 May 6.20 Jan

8 1994 43.30 June 6.20 Jan

9 1995 43.60 June 5.50 Jan

10 1996 40.50 June 4.70 Dec

11 1997 40.10 June 5.60 Jan

12 1998 42.90 June 5.40 Jan

13 1999 41.70 May 6.70 Jan

14 2000 43.00 May 6.00 Jan

15 2001 42.90 May 4.90 Jan

16 2002 44.50 May 5.70 Jan

17 2003 43.00 June 5.50 Jan

18 2004 42.40 June 7.80 Jan

19 2005 43.00 June 5.40 Dec

20 2006 43.60 May 8.30 Dec

Table A.14a: Maximum Pavement Temperature for Bahawalpur

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 29°-24' 29.40 Table A.14b: Minimum Pavement Temperature for Bahawalpur

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



161

Table A.15: Air Temperature Data for Balakot

Station Balakot



1 1987 35.80 July 1.10 Jan

2 1988 36.50 June 4.00 Jan

3 1989 36.30 June 1.30 Jan

4 1990 37.40 June 2.60 Dec

5 1991 36.10 June 0.70 Jan

6 1992 35.50 June 2.90 Jan

7 1993 33.90 June 2.30 Jan

8 1994 35.20 June 4.30 Jan

9 1995 36.10 June 1.70 Jan

10 1996 32.00 July 2.60 Jan

11 1997 31.20 July 2.30 Jan

12 1998 34.10 June 2.90 Jan

13 1999 35.40 June 2.70 Dec

14 2000 35.40 May 2.90 Dec

15 2001 33.90 May 0.80 Jan

16 2002 35.00 June 1.60 Jan

17 2003 35.20 June 2.80 Jan

18 2004 32.30 July 3.10 Jan

19 2005 35.50 June 0.10 Dec

20 2006 34.30 June 1.30 Jan

Table A.15a: Maximum Pavement Temperature for Balakot

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 25°-23' 25.38 Table A.15b: Minimum Pavement Temperature for Balakot

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



162

Table A.16: Air Temperature Data for Chitral

Station Chitral



1 1987 35.20 August -0.30 Jan

2 1988 37.00 July 0.30 Jan

3 1989 34.50 July -1.10 Jan

4 1990 37.10 July -0.80 Jan

5 1991 35.30 July -2.00 Jan

6 1992 35.30 July -0.90 Jan

7 1993 35.10 July -1.10 Jan

8 1994 37.10 July -0.20 Jan

9 1995 37.00 July -1.10 Jan

10 1996 35.30 July -0.90 Dec

11 1997 37.40 July -2.10 Jan

12 1998 36.60 July -1.90 Jan

13 1999 36.70 July 0.20 Dec

14 2000 35.70 July -0.20 Jan

15 2001 37.10 July -0.60 Jan

16 2002 36.30 July 0.50 Dec

17 2003 37.20 July -1.80 Dec

18 2004 35.90 July -1.00 Jan

19 2005 36.40 July -0.70 Dec

20 2006 37.30 July -1.80 Jan

Table A.16a: Maximum Pavement Temperature for Chitral

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 35°-50' 35.83 Table A.16b: Minimum Pavement Temperature for Chitral

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



163

Table A.17: Air Temperature Data for Dera Ismail Khan

Station Dera Ismail Khan



1 1987 41.00 June 5.1 Dec

2 1988 42.30 June 6.2 Jan

3 1989 40.70 June 4.6 Jan

4 1990 41.70 June 6.2 Dec

5 1991 41.20 June 4.9 Jan

6 1992 40.90 June 6.3 Jan

7 1993 40.50 June 4.6 Jan

8 1994 41.30 June 5.3 Jan

9 1995 41.90 June 4.7 Jan

10 1996 39.90 June 2.6 Dec

11 1997 39.50 July 3.3 Jan

12 1998 41.70 June 3.8 Dec

13 1999 41.20 June 4.4 Jan

14 2000 42.20 May 5.3 Jan

15 2001 41.40 May 5.2 Jan

16 2002 42.00 May 4.9 Jan

17 2003 42.60 June 3.5 Jan

18 2004 40.20 May 5.3 Jan

19 2005 42.20 June 2.10 Dec

20 2006 41.70 May 4.1 Jan

Table A.17a: Maximum Pavement Temperature for Dera Ismail Khan

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 31°-50' 31.83 Table A.17b: Minimum Pavement Temperature for Dera Ismail Khan

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



164

Table A.18: Air Temperature Data for Dir

Station Dir



1 1987 32.20 July -2.10 Dec

2 1988 32.40 June -3.10 Dec

3 1989 32.50 June -7.20 Jan

4 1990 33.00 June -4.50 Dec

5 1991 32.80 June -4.70 Jan

6 1992 31.50 June -1.10 Jan

7 1993 32.70 June -2.70 Jan

8 1994 33.90 June -1.10 Dec

9 1995 34.10 June -4.30 Jan

10 1996 31.80 June -3.10 Dec

11 1997 32.20 July -2.90 Jan

12 1998 31.70 July -2.30 Jan

13 1999 33.50 June -2.00 Dec

14 2000 32.70 June -1.70 Jan

15 2001 31.70 June -2.20 Jan

16 2002 33.00 July -2.10 Jan

17 2003 33.50 June -1.10 Jan

18 2004 32.20 June 0.50 Jan

19 2005 33.30 June -1.50 Dec

20 2006 33.40 June -1.60 Dec

Table A.18a: Maximum Pavement Temperature for Dir

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 35°-12' 35.20 Table A.18b: Minimum Pavement Temperature for Dir

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



165

Table A.19: Air Temperature Data for Faisalabad

Station Faisalabad



1 1987 40.10 June 4.30 Dec

2 1988 42.00 May 6.00 Jan

3 1989 39.70 May 4.50 Jan

4 1990 40.90 June 6.00 Dec

5 1991 40.60 July 4.40 Jan

6 1992 41.00 June 6.30 Jan

7 1993 41.10 June 4.60 Jan

8 1994 42.50 June 4.90 Jan

9 1995 41.90 June 4.40 Jan

10 1996 38.10 May 3.10 Dec

11 1997 38.60 June 3.50 Jan

12 1998 40.80 June 3.90 Jan

13 1999 40.60 May 5.80 Dec

14 2000 41.90 May 4.80 Jan

15 2001 41.10 May 4.30 Jan

16 2002 41.60 May 4.60 Jan

17 2003 41.90 June 5.00 Jan

18 2004 39.50 May 6.60 Jan

19 2005 41.90 June 3.20 Dec

20 2006 41.30 May 4.40 Jan

Table A.19a: Maximum Pavement Temperature for Faisalabad

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 31°-25' 31.42 Table A.19b: Minimum Pavement Temperature for Faisalabad

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



166

Table A.20: Air Temperature Data for Gilgit

Station Gilgit



1 1987 36.20 August -4.60 Jan

2 1988 37.60 July -1.80 Dec

3 1989 33.00 June -3.70 Jan

4 1990 38.60 July -2.10 Dec

5 1991 36.10 August -3.10 Jan

6 1992 36.00 July -2.00 Dec

7 1993 34.60 August -3.60 Jan

8 1994 38.20 July -1.80 Dec

9 1995 36.90 July -5.50 Jan

10 1996 35.80 August -5.70 Dec

11 1997 39.70 July -4.30 Jan

12 1998 38.20 July -4.50 Dec

13 1999 37.80 July -6.80 Dec

14 2000 35.30 August -4.00 Jan

15 2001 37.20 July -5.60 Jan

16 2002 36.10 August -4.60 Jan

17 2003 38.20 July -3.20 Dec

18 2004 34.70 July 0.00 Jan

19 2005 35.90 August -6.00 Jan

20 2006 36.80 July -2.50 Dec

Table A.20a: Maximum Pavement Temperature for Gilgit

Maximum Temperature T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 35°-54' 35.90 Table A.20b: Minimum Pavement Temperature for Gilgit

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



167

Table A.21: Air Temperature Data for Islamabad

Station Islamabad


Sr. No. Year Temperature(˚C) Month Temperature(˚C) Month

1 1987 39.00 July 2.90 Jan

2 1988 38.60 June 4.60 Dec

3 1989 38.90 June 2.50 Jan

4 1990 39.50 June 4.90 Dec

5 1991 37.90 June 2.90 Jan

6 1992 38.40 June 5.20 Jan

7 1993 38.10 June 3.00 Jan

8 1994 40.10 June 4.40 Jan

9 1995 40.70 June 2.40 Jan

10 1996 36.00 June 1.20 Dec

11 1997 36.30 June 2.10 Jan

12 1998 38.70 June 3.20 Dec

13 1999 39.10 June 3.60 Dec

14 2000 39.90 June 4.00 Jan

15 2001 34.40 May 2.10 Jan

16 2002 39.00 June 3.00 Jan

17 2003 39.40 June 1.80 Jan

18 2004 36.70 June 5.10 Jan

19 2005 39.90 June 2.00 Dec

20 2006 37.80 June 3.80 Jan

Table A.21a: Maximum Pavement Temperature for Islamabad

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 33°-43' 33.72 Table A.21b: Minimum Pavement Temperature for Islamabad

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



168

Table A.22: Air Temperature Data for Khanpur

Station Khanpur



1 1987 42.60 June 4.60 Dec

2 1988 44.40 May 5.40 Jan

3 1989 41.90 May 4.20 Jan

4 1990 43.00 May 5.20 Dec

5 1991 43.90 June 4.40 Jan

6 1992 44.80 June 6.00 Jan

7 1993 43.70 May 4.20 Jan

8 1994 44.90 May 5.80 Jan

9 1995 44.10 June 3.30 Dec

10 1996 41.30 June 1.90 Jan

11 1997 40.50 June 1.90 Jan

12 1998 42.80 June 1.50 Jan

13 1999 41.90 June 1.90 Jan

14 2000 42.60 June 3.10 Dec

15 2001 43.20 May 3.60 Jan

16 2002 44.40 May 5.00 Jan

17 2003 43.10 June 4.30 Jan

18 2004 42.50 May 6.40 Jan

19 2005 42.50 June 3.20 Dec

20 2006 43.80 May 4.90 Jan

Table A.22a: Maximum Pavement Temperature for Khanpur

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 28°-39' 28.65 Table A.22b: Minimum Pavement Temperature for Khanpur

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



169

Table A.23: Air Temperature Data for Kotli Station Kotli

Daily Maximum Daily Minimum Sr.No. Year Temperature (˚C) Month Temperature(˚C) Month

1 1987 37.30 July 4.60 Jan

2 1988 38.00 June 5.40 Dec

3 1989 38.30 June 4.20 Jan

4 1990 38.70 June 5.20 Dec

5 1991 37.80 June 4.40 Jan

6 1992 37.70 June 6.00 Jan

7 1993 38.50 June 4.20 Jan

8 1994 39.20 June 5.80 Jan

9 1995 40.10 June 3.30 Jan

10 1996 32.90 June 1.90 Dec

11 1997 34.70 June 1.90 Jan

12 1998 36.80 June 1.50 Dec

13 1999 38.20 May 1.90 Dec

14 2000 39.90 May 3.10 Jan

15 2001 37.90 May 3.60 Jan

16 2002 39.10 May 5.00 Jan

17 2003 38.90 June 4.30 Jan

18 2004 36.90 June 6.40 Jan

19 2005 40.00 June 3.20 Dec

20 2006 38.80 May 4.90 Jan

Table A.23a: Maximum Pavement Temperature for Kotli

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 33°-32' 33.53 Table A.23b: Minimum Pavement Temperature for Kotli

Minimum Temperature Tpav = 0.859 Tair +1.7˚C



170

Table A.24: Air Temperature Data for Lahore

Station Lahore



1 1987 40.80 June 7.30 Jan

2 1988 43.10 May 8.20 Dec

3 1989 40.30 May 6.40 Jan

4 1990 40.30 June 8.00 Dec

5 1991 49.30 June 6.40 Jan

6 1992 40.90 June 8.30 Jan

7 1993 41.10 May 6.70 Jan

8 1994 41.70 June 8.30 Jan

9 1995 41.70 June 6.60 Jan

10 1996 38.10 May 7.20 Dec

11 1997 36.70 June 7.30 Jan

12 1998 40.20 June 7.30 Jan

13 1999 39.40 May 8.90 Jan

14 2000 40.40 May 7.90 Jan

15 2001 40.00 May 6.60 Jan

16 2002 41.00 May 8.20 Jan

17 2003 39.80 June 6.60 Jan

18 2004 38.80 May 9.60 Jan

19 2005 40.50 June 7.00 Dec

20 2006 39.50 May 8.40 Jan

Table A.24a: Maximum Pavement Temperature for Lahore

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 31°-34' 31.57 Table A.24b: Minimum Pavement Temperature for Lahore

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



171

Table A.25: Air Temperature Data for Multan

Station Multan



1 1987 41.80 June 4.80 Dec

2 1988 44.10 May 6.60 Jan

3 1989 41.00 June 4.00 Jan

4 1990 42.30 June 6.60 Dec

5 1991 43.10 June 4.40 Jan

6 1992 43.70 June 6.20 Jan

7 1993 43.10 May 5.90 Jan

8 1994 43.60 June 5.90 Jan

9 1995 43.60 June 5.40 Jan

10 1996 40.30 June 4.70 Dec

11 1997 40.20 June 4.90 Jan

12 1998 41.40 May 4.70 Jan

13 1999 42.20 May 6.60 Jan

14 2000 43.40 May 5.30 Jan

15 2001 43.20 May 5.30 Jan

16 2002 43.80 May 4.90 Jan

17 2003 43.50 June 6.00 Jan

18 2004 41.50 May 7.00 Jan

19 2005 42.80 June 3.90 Dec

20 2006 43.00 May 4.40 Jan

Table A.25a: Maximum Pavement Temperature for Multan

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 30°-12' 30.20 Table A.25b: Minimum Pavement Temperature for Multan

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



172

Table A.26: Air Temperature Data for Murree

Station Murree



1 1987 24.20 July 2.40 Jan

2 1988 24.80 May 2.20 Jan

3 1989 25.70 June -0.20 Jan

4 1990 26.40 June 1.80 Dec

5 1991 26.10 June 0.60 Jan

6 1992 26.00 June 2.10 Jan

7 1993 25.90 June -2.00 Jan

8 1994 28.00 June -3.50 Jan

9 1995 28.90 June -2.00 Jan

10 1996 24.80 June -2.10 Jan

11 1997 23.70 June 0.10 Dec

12 1998 26.60 June -2.00 Jan

13 1999 25.90 June -3.50 Jan

14 2000 25.40 June -5.30 Jan

15 2001 25.90 May -4.70 Jan

16 2002 26.20 May -4.80 Jan

17 2003 27.10 June -4.40 Jan

18 2004 24.30 July -4.00 Jan

19 2005 27.00 June -3.50 Jan

20 2006 26.80 May -3.40 Jan

Table A .26a: Maximum Pavement Temperature for Murree

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 33°-55' 33.92 Table A .26b: Minimum Pavement Temperature for Murree

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



173

Table A .27: Air Temperature Data for Muzaffarabad

Station Muzaffarabad



1 1987 38.00 July 3.10 Jan

2 1988 39.30 May 5.00 Dec

3 1989 37.60 June 3.00 Jan

4 1990 38.60 June 3.60 Dec

5 1991 37.60 June 2.50 Jan

6 1992 37.10 June 4.20 Jan

7 1993 38.00 June 3.10 Jan

8 1994 39.00 June 4.50 Jan

9 1995 39.90 June 2.70 Jan

10 1996 34.90 June 2.60 Jan

11 1997 34.50 June 2.60 Jan

12 1998 37.80 June 2.30 Dec

13 1999 38.80 June 3.50 Dec

14 2000 38.90 May 3.60 Jan

15 2001 37.60 May 2.50 Jan

16 2002 37.90 June 2.40 Jan

17 2003 38.70 June 2.80 Jan

18 2004 35.90 June 4.40 Jan

19 2005 37.00 June 3.30 Jan

20 2006 38.00 May 1.20 Jan

Table A .27a: Maximum Pavement Temperature for Muzaffarabad

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 24°-24' 34.40 Table A .27b: Minimum Pavement Temperature for Muzaffarabad

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



174

Table A.28: Air Temperature Data for Parachinar

Station Parachinar



1 1987 31.00 July -0.70 Jan

2 1988 30.90 June 0.10 Jan

3 1989 31.20 June -2.20 Jan

4 1990 31.30 June -0.20 Feb

5 1991 31.20 June -2.40 Jan

6 1992 30.40 June -2.90 Feb

7 1993 30.50 June -6.20 Jan

8 1994 32.10 June -3.10 Feb

9 1995 32.20 June -6.20 Jan

10 1996 30.10 June -6.50 Jan

11 1997 31.00 July -7.40 Jan

12 1998 30.70 July -8.70 Jan

13 1999 32.20 June -9.10 Jan

14 2000 31.10 June -7.50 Feb

15 2001 31.10 May -7.80 Jan

16 2002 31.60 June -7.60 Jan

17 2003 32.10 June -8.40 Jan

18 2004 30.10 July -6.80 Jan

19 2005 30.40 June -5.00 Jan

20 2006 30.10 July -5.80 Jan

Table A .28a: Maximum Pavement Temperature for Parachinaar

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 33°-54' 33.90 Table A .28b: Maximum Pavement Temperature for Parachinaar

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



175

Table A.29: Air Temperature Data for Peshawar Station Peshawar



1 1987 40.50 July 4.20 Jan

2 1988 39.90 June 6.30 Jan

3 1989 40.90 June 3.80 Jan

4 1990 40.80 June 5.00 Dec

5 1991 40.00 June 3.40 Jan

6 1992 43.30 June 5.30 Jan

7 1993 40.10 June 3.00 Jan

8 1994 41.90 June 4.90 Jan

9 1995 42.70 June 2.60 Jan

10 1996 39.80 June 2.50 Dec

11 1997 38.60 June 2.70 Jan

12 1998 40.50 June 3.80 Jan

13 1999 42.30 June 4.60 Dec

14 2000 40.40 May 4.50 Jan

15 2001 39.60 May 3.90 Jan

16 2002 39.50 June 4.40 Jan

17 2003 41.00 June 5.20 Jan

18 2004 38.50 June 6.10 Jan

19 2005 40.80 June 3.80 Dec

20 2006 39.40 May 4.70 Jan

Table A.29a: Maximum Pavement Temperature for Peshawar

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 34°-01' 34.02 Table A.29b: Minimum Pavement Temperature for Peshawar

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



176

Table A.30: Air Temperature Data for Sialkot

Station Sialkot



1 1987 40.20 June 5.2 Dec

2 1988 40.80 May 5.9 Dec

3 1989 38.80 June 3.6 Jan

4 1990 39.90 June 6.3 Jan

5 1991 38.70 June 5 Jan

6 1992 39.30 June 6.3 Dec

7 1993 40.00 June 4.5 Jan

8 1994 41.00 June 6.7 Jan

9 1995 42.10 June 4.3 Jan

10 1996 36.90 May 2.7 Dec

11 1997 37.00 June 2.50 Jan

12 1998 40.40 June 4.8 Jan

13 1999 39.30 May 5.4 Dec

14 2000 40.20 May 5.2 Dec

15 2001 39.40 May 4 Jan

16 2002 41.00 May 4.8 Dec

17 2003 40.30 June 4.7 Jan

18 2004 38.70 May 6.8 Jan

19 2005 41.20 June 3.1 Dec

20 2006 39.50 May 5.3 Jan

Table A.30a: Maximum Pavement Temperature for Sialkot

Maximum Temperature

T20mm = [Tair -0.00618 Lat2 + 0.2289 Lat + 42.2] x 0.9545 -17.78



Lat The Geographical Latitude of Project in Degrees 32°-30' 32.50 Table A.30b: Minimum Pavement Temperature for Sialkot

Minimum Temperature

Tpav = 0.859 Tair +1.7˚C



177

Annexure B

178

Table B1: Performance Based Requirements for Binder

PG-52

PG-58

PG-64

PG-70

Performance Grade

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

Average 7-day Maximum Pavement Design Temperature, (°C)

<52 <58 <64 <70

Minimum Pavement Design Temperature (°C)

> -10

> -16

> -22

> -28

> -34

> -40

> -46

> -16

> -22

> -28

> -34

> -40

> -16

> -22

> -28

> -34

> -40

> -10

> -16

> -22

> -28

Original Binder

Flash Point Temperature, T48: Minimum (°C)

230

Viscosity, ASTM D 4402; Maximum, 3 Pa.s (3000 Cp), Test Temp (°C)

135

Dynamic Shear , TP5; G*/sin δ, Minimum, 1.00 kPa Test Temp @10 rad/sec, (°C)

52 58 64

70

Continued...

179

Rolling Thin Film Oven ( T240) or Thin Film Oven ( T179) Residue

Mass Loss, Maximum, % 1.00

Dynamic Shear , TP5; G*/sin δ, Minimum, 2.20 kPa Test Temp @10 rad/sec, (°C)

52 58 64 70

Pressure Aging Vessel Residue (PPI) PAV Aging Temperature, (°C) 90 100 100 100(110)

Dynamic Shear , TP5; G*/sin δ, Maximum, 5000 kPa; Test Temp @10 rad/sec, (°C)

25

22

19

16

13

10

7

25

22

19

16

13

28

25

22

19

16

34

31

28

25

Physical Hardening Report Creep Stiffness, TPI S, Maximum, 300 MPa m value, Minimum, 0.300 Test Temp, @ 60 sec, (°C)

0

-6

-12

-18

-24

-30

-36

-6

-12

-18

-24

-30

-6

-12

-18

-24

-30

0

-6

-12

-18

Direct Tension,TP3: Faiure Strain, Minimum, 1.0 % Test Temperature @ 1.0 mm/min, (°C)

0

-6

-12

-18

-24

-30

-36

-6

-12

-18

-24

-30

-6

-12

-18

-24

-30

0

-6

-12

-18

180

Table B2: Station wise Performance Grading

Selection of Performance Grades Maximum Temperature Min. Temperatures

Sr. No. Station Pavement

Temperature (°C)

Pavement Temperature including 98% Reliability (°C)

Performance Grade

Pavement Temperature

(°C)

Performance Grade

Selected Grade

1 Dalbandin 66.79 70.79 76 1.01 -4 PG 76-4

2 Hyderabad 64.46 68.46 70 9 -4 PG 70-4

3 Jacobabad 68.21 72.21 76 6.17 -4 PG 76-4

4 Karachi 59.33 63.33 64 9.43 -4 PG 64-4

5 Lasbella 65.31 69.31 70 7.8 -4 PG 70-4

6 Nawabshsh 68.16 72.16 76 5.57 -4 PG 76-4

7 Nokkundi 66.37 70.37 70 2.73 -4 PG 70-4

8 Pasni 59.45 63.45 64 10.55 -4 PG 64-4

Continued...

181

Selection of Performance Grades Maximum Temperature Min. Temperatures

Sr. No. Station Pavement

Temperature (°C)

Pavement Temperature including 98% Reliability (°C)

Performance Grade


(°C)

Performance Grade

Selected Grade

9 Quetta 59.55 63.55 64 -2.60 -4 PG 64-4

10 Rohri 66.97 70.97 76 5.91 -4 PG 76-4

11 Sibbi 68.58 72.58 76 5.74 -4 PG 76-4

12 Zhob 60.42 64.42 70 -4.66 -10 PG 70-10

13 Astor 49.98 53.98 58 -8.69 -10 PG 58-10

14 Bahawalpur 65.65 69.65 70 5.74 -4 PG 70-4

15 Balakot 58.84 62.84 64 1.79 -4 PG 64-4

Continued...

182

Max. Temperatures Min. Temperatures

Sr. No. Station Pavement Temperature

(°C)

Pavement Temperature including 98% Reliability

(°C)

Performance Grade


(°C)

Performance Grade

Selected Grade

16 Chitral 58.24 62.24 64 -0.1 -4 PG 64-4

17 Dera Ismail Khan 63.69 67.69 70 3.5 -4 PG 70-4

18 Dir 54.88 58.88 64 -4.48 -10 PG 64-10

19 Faisalabad 63.59 67.59 70 4.36 -4 PG 70-4

20 Gilgit 59.33 63.33 64 -4.14 -10 PG 64-10

21 Islamabad 61.15 65.15 70 2.73 -4 PG 70-4

22 Khanpur 66.23 70.23 76 2.99 -4 PG 76-4

23 Kotli 60.76 64.76 70 2.99 -4 PG 70-4

24 Lahore 64.26 68.26 70 7.2

-4 PG 70-4

Continued...

183

Max. Temperatures Min. Temperatures

Sr. No. Station Pavement Temperature

(°C)

Pavement Temperature including 98% Reliability

(°C)

Performance Grade


(°C)

Performance Grade

Selected Grade

25 Multan 65.36 69.36 70 5.05 -4 PG 70-4

26 Murree 49.14 53.14 58 -2.85 -4 PG 58-4

27 Muzaffarabad 60.29 64.29 70 2.73 -4 PG 70-4

28 Parachinar 53.49 57.49 58 -6.12 -10 PG 58-10

29 Peshawar 63.04 67.04 70 3.85 -4 PG 70-4

30 Sialkot 62.48 66.48 70 3.85 -4 PG 70-4

184

Annexure C

185

Table C1: Performance Based Binder Properties of 60/70 Grade Bitumen


Pressure Aging Vessel

Temperature: 100 Precise SHRP Grade PG 62.6 -

24.5 Sample: PAKISTAN BASE, ATTOCK 60/70 PEN, NEAT

Passing Temp for PAV DSR

(62.6-24.5)/2 + 4 = 23.05

Precise SHRP DELTA:

62.6 + 24.5 = 87.1

HANDLING AND SAFETY PROPERTIES TEST SPECIFICATION RESULT TEST SPECIFICATION RESULT

Flash Point, COC, 0C Min. 230 0C Solubility, Wt. % Min. 99 % RTFO Mass Loss, Wt. % Max. 1.00 0.90% Specific Gravity NA

Brookfield Viscosity, Pass Max. 3 0.226 Penetration PROGRESSION RESULTS

SAMPLE PARAMETER TEMP

MIX PERFORMANCE PROPERTIES Unaged 1 kPa @ 62.6

UNAGED RTFO PAV USING RTFO RESIDUE RTFO 2.2 kPa @ 63.6

Direct Tension PAV-DS 5 Mpa @ 23.6

PAV-BBR 300 Mpa @ -14.5

PAV-BBR 0.300 SLOPE @ -15.9

Test 0C G*Sin(d)

MIN 1.0_kPa

Phase Angle DEG

G*Sin(d) MIN

2.2_kPa Phase Angle DEG

G*XSin(d) MAX

5000 kPa Phase Angle DEG

BBR-S MAX

300_Mpa

BBR-m

MIN 0.300

Strain 1mm/min

MIN 1.0%

Stress 1mm/min

Mpa

DSR 70 0.356 88.4

DSR 64 0.81 87.6 2.083 2.1 CRITICAL CRACKING TEMPERATURE

DSR 58 1.939 86.3 4.365 83.4 << SHRP TEMP For Pavement Constant = 16 -21.2

DSR 52 For Pavement Constant = 18 -20.5

DSR 46

Continued...

186




24.5 Sample: PAKISTAN BASE, ATTOCK 60/70 PEN, NEAT


(62.6-24.5)/2 + 4 = 23.05

Precise SHRP DELTA:

62.6 + 24.5 = 87.1

DSR 40 AGING RATIO @ SHRP TEMP

DSR 31

DSR 28 Unaged G*/Sin(d) @ SHRP TEMP 1.939

DSR 25 4012 49.8

DSR 22 6339 46 RTFO G*/Sin(d) @ SHRP TEMP 4.365

DSR 19 RATIO 2.25

DSR 16

DSR 13 DSR PHASE ANGLES

DSR 10 Unaged When 1/J" = 1 87.2

DSR 7 RTFO When 1/J" = 2.2 8.1

DSR 4 PAV When G" = 5000 48

DSR 1 DSR -2 DSR -5 BBR -6 BBR -9 0.89 2.26 BBR -12 227 0.336 0.67 2.26 BBR -15 BBR -18 444 0.281 0.3 2.08 BBR -21 BBR -24

187

Table C2: Performance Based Binder Properties of Polymer Modified Bitumen (1.6% Elvaloy 4160)




23.3 Sample: 01-102A - Pakistan Attock 60 - 70 Pen 1.6% 4170, 0.7% SPA, Overnight cook, 1600C


(78.6-23.3)/2 + 4 = 31.65

Precise SHRP DELTA:

78.6 + 23.3 = 101.9

HANDLING AND SAFETY PROPERTIES TEST SPECIFICATION RESULT TEST SPECIFICATION RESULT

Flash Point, COC, 0C Min. 230 0C Solubility, Wt. % Min. 99 % RTFO Mass Loss, Wt. % Max. 1.00 1.02% Specific Gravity NA

Brookfield Viscosity, Pass Max. 3 1.252 Penetration PROGRESSION RESULTS

SAMPLE PARAMETER TEMP MIX PERFORMANCE PROPERTIES Unaged 1 kPa @ 78.6

UNAGED RTFO PAV USING RTFO RESIDUE RTFO 2.2 kPa @ 82.8 Direct Tension PAV-DS 5 Mpa @ 22.7

PAV-BBR 300 Mpa @ -13.3

PAV-BBR 0.300 SLOPE @ -15.1

Test 0C G*Sin(d)

MIN 1.0_kPa

Phase Angle DEG

G*Sin(d) MIN

2.2_kPa Phase Angle DEG

G*XSin(d) MAX

5000 kPa Phase Angle DEG

BBR-S MAX

300_Mpa

BBR-m

MIN 0.300

Strain 1mm/min

MIN 1.0%

Stress 1mm/min

Mpa

DSR 88 1.396 59.6

DSR 82 0.728 67.4 2.374 58.3 CRITICAL CRACKING TEMPERATURE

DSR 76 1.281 65.8 4.005 57.3 << SHRP TEMP For Pavement Constant = 16 -23.6

DSR 70 For Pavement Constant = 18 -22.6

DSR 64

Continued...

188




23.3 Sample: 01-102A - Pakistan Attock 60 - 70 Pen 1.6% 4170, 0.7% SPA, Overnight cook, 1600C


(78.6-23.3)/2 + 4 = 31.65

Precise SHRP DELTA:

78.6 + 23.3 = 101.9

DSR 58 AGING RATIO @ SHRP TEMP

DSR 31

DSR 28 Unaged G*/Sin(d) @ SHRP TEMP 1.281

DSR 25 3828 40.8

DSR 22 5452 39 RTFO G*/Sin(d) @ SHRP TEMP 4.005

DSR 19 RATIO 3.13

DSR 16

DSR 13 DSR PHASE ANGLES

DSR 10 Unaged When 1/J" = 1 66.5

DSR 7 RTFO When 1/J" = 2.2 58.6

DSR 4 PAV When G" = 5000 39.4

DSR 1 DSR -2 DSR -5 BBR -6 BBR -9 BBR -12 259 0.329 1.5 3.91 BBR -15 BBR -18 516 0.273 0.77 5.16 BBR -21 BBR -24

189

Annexure D

190

Table D1: Summary Results of Uniaxial Loading Strain Test

Test Conditions Mix Type

Superpave SMA Marshall

Stress Level

Temperature (°C) Resilient

Strain (%) Accumulated

Strain (%)

Resilient Modulus

(MPa)




Resilient Modulus

(MPa)




Resilient Modulus

(MPa)


25 0.014 0.15 734 67 0.026 0.36 278 31 0.019 0.39 410 30

40 0.027 0.28 398 46 0.033 0.45 262 23 0.034 0.85 300 15 100KPa

55 0.031 0.38 609 42 0.059 0.57 100 18 0.039 1.35 137 12

25 0.036 0.31 714 112 0.046 0.77 440 41 0.043 0.5 673 60

40 0.059 0.35 577 72 0.097 1.5 317 20 0.067 1.14 477 26 300Kpa

55 0.1 0.47 517 53 0.11 4.5 100 10 0.13 2.18 249 14

25 0.04 0.33 734 83 0.097 1.07 554 47 0.045 1.0 521 62

40 0.071 0.44 556 76 0.107 3.5 453 14 0.08 3.05 477 14 500Kpa

55 0.11 0.70 517 70 0.123 4.5 100 13 0.14 4.4 330 14

191

Table D2: Summary Results of Dynamic Modulus Test at 25°

Mix Type MARSHALL SMA SUPERPAVE

Performance Based

Properties

Dynamic Modulus (MPa) at 25°C Permanent Strain at 25°C Dynamic Modulus (MPa) at

25°C Permanent Strain at 25°C Dynamic Modulus (MPa) at 25°C Permanent Strain at 25°C

Frequency (Hz)

300 kPa

500 kPa

700 kPa

300 kPa

(10-4)

500 kPa

(10-4)

700 kPa

(10-4)

300 kPa

500 kPa

700 kPa

300 kPa

(10-4)

500 kPa

(10-4)

700 kPa

(10-4)

300 kPa

500 kPa

700 kPa

300 kPa

(10-4)

500 kPa

(10-4)

700 kPa

(10-4)

25 7000 7631 7360 5.6 9.11 6.13 5558 7223 7066 12.48 8.51 8.54 7700 11649 8942 2.27 1.78 4.35

10 4901 5700 5773 7 15.68 11.38 3981 5076 5137 18.57 13.14 13.74 6294 9238 7048 4.32 3.03 6.58

5 3961 4424 4463 7.7 19.82 15 3239 4087 4149 22.9 16.65 17.21 5070 7843 5884 5.6 4.56 7.7

1 2259 2550 2752 8.7 26.55 20.09 1919 2338 2567 30.73 23.26 23.5 3316 5249 3833 7.75 7.57 9.5

0.5 1784 1977 2254 9 28.88 21.79 1469 1842 2116 33.49 25.77 25.87 2592 4420 3192 8.49 8.52 10.09

0.1 1104 1179 1474 9.8 35.3 26.23 867 1081 1358 41.94 33.32 32.67 1647 2800 2080 9.52 10.86 11.88

192

Table D3: Summary Results of Dynamic Modulus Test at 40°C


Performance Based

Properties

Dynamic Modulus (MPa) at 40°C Permanent Strain at 40°C Dynamic Modulus (MPa) at

40°C Permanent Strain at 40°C Dynamic Modulus (MPa) at 40°C Permanent Strain at 40°C

Frequency (Hz)

150 kPa

200 kPa

250 kPa

150 kPa

(10-4)

200 kPa

(10-4)

250 kPa

(10-4)

150 kPa

200 kPa

250 kPa

150 kPa

(10-4)

200 kPa

(10-4)

250 kPa

(10-4)

150 kPa

200 kPa

250 kPa

150 kPa

(10-4)

200 kPa

10-4)

250 kPa

(10-4)

25 2654 3450 2556 4.27 4.31 5.95 7066 3832 1703 31.96 9.25 69.54 8942 5077 5145 3.88 4.1 4.35

10 1876 2367 1846 4.58 4.75 6.87 5137 2474 1216 39.35 11.24 87.69 7048 3871 3698 4.45 4.59 4.77

5 1502 1854 1449 4.73 5.01 7.44 4149 2032 994 43.53 12.49 96.53 5883 2927 2883 4.66 4.83 4.99

1 931 1132 950 4.89 5.19 8.09 2570 1134 643 47.96 13.34 104.87 3833 1680 1665 4.75 5.06 5.21

0.5 794 938 829 5.01 5.31 8.28 2116 898 469 49.01 13.49 106.61 3192 1341 1344 4.86 5.14 5.32

0.1 586 665 628 5.18 5.42 8.84 1358 542 454 50.69 13.61 109.35 2080 850 889 5.03 5.27 5.47

193

Table D4: Summary Results of Dynamic Modulus Test at 55°C


Performance Based

Properties

Dynamic Modulus (MPa) at 55°C Permanent Strain at 55°C Dynamic Modulus (MPa)

at 55°C Permanent Strain at 55°C Dynamic Modulus (MPa) at 55°C Permanent Strain at 55°C

Frequency (Hz)

35 kPa

50 kPa

65 kPa

35 kPa

(10-4)

50 kPa

(10-4)

65 kPa

(10-4)

35 kPa

50 kPa 65 kPa

35 kPa

(10-4)

50 kPa

(10-4)

65 kPa

(10-4) 35 kPa 50 kPa 65 kPa

35 kPa

(10-4)

50 kPa

(10-4)

65 kPa

(10-4)

25 379 421 435 19.74 7.84 7.09 427 464 485 16.31 5.91 6.2 735 742 737 2.27 2.31 2.94

10 299 327 346 22.87 9.52 8.39 341 372 396 18.51 6.21 6.91 558 549 571 2.49 2.37 2.99

5 273 296 310 24.44 10.5 9.19 315 340 361 19.33 6.34 7.11 479 484 493 2.61 2.41 3.03

1 229 247 261 26.45 11.75 9.96 260 286 303 19.96 6.45 7.23 357 373 386 2.74 2.46 3.12

0.5 205 227 246 27.07 12.16 10.19 240 269 289 20.06 6.57 7.36 323 337 351 2.77 2.53 3.25

0.1 180 199 220 28.74 13.28 10.59 223 254 212 20.93 6.73 7.5 264 286 305 3 2.67 3.37

194

LIST OF PUBLICATIONS

1. PERFORMANCE GRADING (PG) OF ASPHALT FOR IMPLEMENTING

SUPERPAVE MIX DESIGN METHOD TO RESIST RUTTING

Authors: Kamran Muzaffar Khan and Prof.Dr.Mumtaz Ahmed Kamal

Proceedings of Sixth International Conference on Sustainable Aggregates,

Asphalt Technology and Pavement Engineering (21-22Feb 2007), Liverpool John

Moores University UK.

2. IMPACT OF SUPERPAVE MIX DESIGN METHOD ON RUTTING

BEHAVIOUR OF FLEXIBLE PAVEMENTS IN PAKISTAN

Authors: Kamran Muzaffar Khan and Prof.Dr.Mumtaz Ahmed Kamal

Accepted for Publication at Arabian Journal of Science and Engineering (AJSE)

2008

3. PERFORMANCE OF SUPERPAVE AND OTHER MIXES AGAINST

ASPHALT RUTTING

Authors: Kamran Muzaffar Khan and Prof. Dr.Mumtaz Ahmed Kamal

Journal of Transportation Engineering, Institution of Civil Engineers (ICE)

(Under Review Process)

Documents

Impact of Superpave Mix Design Method on Rutting Behaviour ...prr.hec.gov.pk/jspui/bitstream/123456789/1213/1/765S.pdf · I certify that research work titled “Impact of Superpave