PERFORMANCE OF CORROSION INHIBITING ADMIXTURES

IN HAWAIIAN CONCRETE IN A MARINE ENVIRONMENT 

FINAL PROJECT REPORT by

Joshua Ropert, MS

and Ian N. Robertson. Ph.D., S.E., Professor

University of Hawaii at Manoa

Prepared in cooperation with:

State of Hawaii Department of Transportation

Harbors Division

and

U.S. Department of Transportation Federal Highway Administration

Research Report UHM/CEE/12-04

September 30, 2012

  Technical Report Documentation Page 1. Report No.

 2. Government Accession No.

 3. Recipient's Catalog No.

 4. Title and Subtitle

PERFORMANCE OF CORROSION INHIBITING ADMIXTURES IN HAWAIIAN CONCRETE IN A MARINE ENVIRONMENT               

5. Report Date

      September 30, 2012

6. Performing Organization Code

 7. Author(s)

      Ropert, J., and Robertson, I.N. 8. Performing Organization Report No.

UHM/CEE/12-04

9. Performing Organization Name and Address    Department of Civil and Environmental Engineering University of Hawaii at Manoa 2540 Dole St. Holmes Hall 383 Honolulu, HI 96822

10. Work Unit No. (TRAIS)

 11. Contract or Grant No.

51397 12. Sponsoring Agency Name and Address     Hawaii Department of Transportation Highways Division 869 Punchbowl Street Honolulu, HI 96813 

13. Type of Report and Period Covered              Final 

14. Sponsoring Agency Code

 15. Supplementary Notes   Prepared in cooperation with the U.S. Department of Transportation, Federal Highway Administration

16. Abstract

A long-term field exposure study was conducted to evaluate the durability of reinforced concrete specimens exposed to a marine environment made with Hawaiian aggregates. Twenty five field panels were constructed and placed in the tidal zone at Pier 38 in Honolulu Harbor on the island of Oahu in 2002 and 2003. The panels were removed from Pier 38 in 2012, after 9 to 10 years of exposure. In addition to control specimens, these panels including various corrosion inhibiting admixtures and pozzolans intended to reduce the chloride penetration rates through the concrete and delay the onset of chloride induced corrosion of the reinforcing steel. The panels were monitored for half-cell potential and chloride concentration through the cover concrete at various intervals during field exposure. This report provides an overview of the results of this study, including evaluation of the ability of the computer program Life-365 to predict the chloride penetration rates. Recommendations are provided for design of future concrete exposed to a marine environment in Hawaii and application of Life-365 to life cycle estimation for such concrete. Suggestions are also given for future research needs in this important field of study.

17. Key Words

Long‐term exposure, reinforcement corrosion, marine environment, chloride concentration, LIFE 365, corrosion inhibiting admixtures, pozzolans

18. Distribution Statement

 

19. Security Classif. (of this report) Unclassified 

20. Security Classif. (of this page) Unclassified

21. No. of Pages 179

22. Price

Form DOT F 1700.7 (8‐72) Reproduction of completed page authorized 

 

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Acknowledgements

This report is based primarily on a Master of Science thesis prepared by Joshua Ropert, but includes data collected by numerous graduate and undergraduate students at UH Manoa over the past ten years. All of these students have worked under my direction at the Department of Civil and Environmental Engineering at the University of Hawaii at Manoa, and their considerable effort and contributions to this project are gratefully acknowledged.

The authors also acknowledge the considerable contributions made by the State of Hawaii Department of Transportation (HDOT), Ameron Hawaii, and Hawaiian Cement for this project. Funding for this research project was provided by the HDOT under grant number 51397. Aggregates and other constituents for the concrete mixtures were donated by Ameron Hawaii and Hawaiian Cement.

This project was initiated by Dr. Craig Newtson as part of a larger study of durability of concretes made with Hawaiian aggregates and exposed to a marine environment. After relocating to New Mexico State University, Dr. Newtson continued to provide guidance and advice for this study, and his input is gratefully acknowledged.

Dr. Gaur Johnson provided considerable assistance during fabrication and deployment of the field corrosion specimens, as well as technical support with data collection during this study. His numerous contributions are greatly appreciated.

The authors are also grateful to Drs. H. Ronald Riggs, David T. Ma, Si-Hwan Park, Gregor Fischer, Ricardo Archilla, Farshad Rajabipour and Panos Prevedorous for reviewing the various Master of Science theses on which this report is based. Special thanks are also extended to the Holmes Hall structures laboratory staff, particularly Andy Oshita, Miles Wagner and Mitch Pinkerton, for their assistance throughout the duration of this study.

The contents of this report reflect the view of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the State of Hawaii, Department of Transportation or the Federal Highway Administration. This report does not constitute a standard, specification or regulation.

 

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EXECUTIVE SUMMARY

A long-term field exposure study was conducted to evaluate the durability of reinforced concrete specimens exposed to a marine environment made with Hawaiian aggregates. Twenty five field panels were constructed and placed in the tidal zone at Pier 38 in Honolulu Harbor on the island of Oahu in 2002 and 2003. The panels were removed from Pier 38 in 2012, after 9 to 10 years of exposure. In addition to control specimens, these panels including various corrosion inhibiting admixtures and pozzolans intended to reduce the chloride penetration rates through the concrete and delay the onset of chloride induced corrosion of the reinforcing steel. The panels were monitored for half-cell potential and chloride concentration through the cover concrete at various intervals during field exposure. This report provides an overview of the results of this study, including evaluation of the ability of the computer program Life-365 to predict the chloride penetration rates. Recommendations are provided for design of future concrete exposed to a marine environment in Hawaii and application of Life-365 to life cycle estimation for such concrete. Suggestions are also given for future research needs in this important field of study.

The concrete mixtures used in this study were based on typical mixtures used by the Harbors Division of the Hawaii Department of Transportation. Water-cement ratios range from 0.35 to 0.40. All coarse and fine aggregates were obtained from either Halawa quarry (Hawaiian Cement) or Kapaa quarry (Ameron), both located on the island of Oahu. The corrosion inhibiting admixtures included in the field panel mixtures were Darex Corrosion Inhibitor (DCI), Rheocrete CNI, Rheocrete 222+, FerroGard 901, Xypex Admix C-2000, latex modifier, and Kryton KIM. The pozzolanic admixture materials included fly ash and silica fume.

Observations and Conclusions

Half-cell readings were taken on the top surface of the panels at various intervals during the field exposure. These readings provided an indication of the probability that corrosion had initiated on the reinforcing steel in the panel. Field observations confirmed the presence of surface cracks and rust products on some of the panels after as little as 7 years exposure in the tidal zone.

Table E-1-1 shows the results of analysis of the half cell readings and visual inspection of the field panels. The panel mixture details are listed in columns 2 to 5. Column 6 lists the number of months before the half-cell readings indicated a 50% probability that corrosion had initiated somewhere in the panel, while column 7 lists the months before the half-cell readings indicated a 90% probability that corrosion had initiated. Columns 8 and 9 provide the type of observed damage due to corrosion and the number of months exposure at which the damage was observed, respectively. The cell coloring indicates whether the panel performance was good (green), fair (orange) or poor (red) based on the half-cell and visual inspections.

 

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Table E-1-1: Results of half-cell and visual inspection of field corrosion specimens

Based on the results summarized in Table E-1-1, it was concluded that control mixtures with a lower water-cement ratio (0.35) performed better than those made with higher ratio (0.40) as would be expected. The calcium nitrite based admixtures, DCI and Rheocrete CNI, indicated better corrosion resistance with a higher dosage of 4 gal/yd3 (20 l/m3) compared to mixtures with 2 gal/yd3 (10 l/m3). Panels with 15% cement replaced with fly ash provided consistently good results. Panels with 5% cement replaced with silica fume showed good performance except for one panel where it appeared that poor dispersion of the silica fume during mixing led to pockets of silica fume powder in the final specimen. The panel using 2% Kryton Kim performed well during the field exposure. Panels using the remaining admixtures, Rheocrete 222+, FerroGard 901, Xypex Admix C-2000 and latex modifier exhibited inconsistent to poor results.

50% >90% Panel

Months Months Damage Months

(1) (2) (3) (4) (5) (6) (7) (8) (9)

1 0.4 Kapaa None Control 40 40 Crack 84

7 0.35 Kapaa None Control 24 62 None ‐

2 0.4 Halawa None Control 40 40 Cracks and Rust 84

3 0.4 Kapaa DCI 10l/m3‐ ‐ None ‐

3A 0.4 Kapaa DCI 20l/m3‐ ‐ None ‐

5 0.4 Kapaa CNI 10l/m324 24 None ‐

6 0.4 Kapaa CNI 10l/m324 46 Rust 80

5A 0.4 Kapaa CNI 20l/m358 ‐ None ‐

4 0.4 Halawa CNI 10l/m340 40 Crack and rust 84

15 0.4 Kapaa Rheocrete 5l/m362 62 Crack and rust 84

16 0.4 Kapaa Rheocrete 5l/m324 24 None ‐

17 0.4 Halawa Rheocrete 5l/m324 40 Rust 84

17A 0.4 Halawa Rheocrete 5l/m358 ‐ None ‐

20 0.4 Kapaa FerroGard 15l/m337 60 Crack and rust 80

18 0.4 Halawa FerroGard 15l/m340 62 Crack and rust 84

19 0.4 Halawa FerroGard 15l/m349 62 Rust 84

21 0.4 Kapaa Xypex 2% 20 37 Crack and rust 84

14 0.4 Kapaa Latex Mod. 5% 30 38 Crack and rust 74

22 0.4 Kapaa Kryton Kim 2% 24 ‐ None ‐

8 0.36 Kapaa Silica Fume 5% 20 ‐ None ‐

9 0.36 Kapaa Silica Fume 5% 13 52 Crack and rust 74

10 0.36 Kapaa Silica Fume 5% 64 ‐ None ‐

11 0.36 Kapaa Fly Ash 15% 20 80 None ‐

12 0.36 Halawa Fly Ash 15% 84 ‐ None ‐

13 0.36 Halawa Fly Ash 15% ‐ ‐ None ‐

Field Panel Details Field Half‐cell Field Panel Damage

Field 

Panel

w/c 

Ratio

Aggregate 

Source

Inhibiting 

Admixture

Admixture 

Dosage

 

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Another focus of this study was to compare the chloride concentration results measured in the field panels to those obtained from the computer program Life-365 which is designed to predict chloride concentrations in reinforced concrete. Since Life-365 only provides predictions for certain admixtures, this portion of the study was limited to the control panels and those with DCI, Rheocrete CNI, Rheocrete 222+, fly ash and silica fume.

Modified parameters were needed for all of the predicted chloride concentrations of Life-365 as most of the program default parameters overestimated the concentrations through the depth of the specimen when compared to the field panel results. In order to improve predictions of chloride ingress provided by Life-365, the default parameters used in the program should be replaced with those shown in Table E-2. These proposed parameters were shown to provide much closer agreement with the measured chloride concentrations through the cover concrete, but particularly at the top surface of the steel reinforcement.

Table E-2: Life-365 default and proposed parameters.

Life-365 Default Parameters Proposed Parameters

Diffusion

Coefficient Diffusion Decay

Index Diffusion

Coefficient Diffusion Decay

Index

Specimen D28 m D28 m

Control panels with 0.40 w/c ratio

7.94x10-12 0.20 5.50x10-12 0.38

Panels with DCI or CNI and 0.40 w/c ratio

7.94x10-12 0.20 5.50x10-12 0.38

Panels with Rheocrete 222+ and 0.40 w/c ratio

7.94x10-12 0.20 5.50x10-12 0.38

Control panel with 0.35 w/c ratio

6.03x10-12 0.20 6.50x10-12 0.53

Panels with 15% Fly Ash and 0.36 w/c ratio

6.37x10-12 0.32 3.00x10-12 0.35

Panels with 5% silica fume and 0.36 w/c ratio

2.71x10-12 0.20 2.50x10-12 0.30

Recommendations

Design of concrete using Hawaiian aggregates for exposure in a marine or coastal environment should observe the following recommendations based on this study:

1. Use a water to cementitious material ratio as low as possible, but not greater than 0.40.

2. Include fly ash with at least 15% replacement of cement, or silica fume with at least 5% replacement of cement. Mixing must ensure that the fly ash and silica fume, in particular, are well distributed throughout the concrete.

3. Include Darex DCI or Rheocrete CNI at minimum dosages of 4 gal/cuyd (20 l/m3).

4. As added protection, consider including Kryton Kim at 2% by weight of cement.

 

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Future Research Needs

Based on the results of this and other similar studies of the effect of reinforcing steel corrosion on reinforced concrete exposed to a marine environment, the following future research needs were identified:

1. Perform long-term field exposure studies on concrete mixtures using a combination of corrosion inhibiting measures to observe the combined effect. For example, combining fly ash and effective corrosion inhibitors like DCI, CNI and Kryton Kim to determine how much the combination improves performance compared with each individual admixture and the original control mixture.

2. Consider new corrosion inhibiting admixtures that have become available since initiation of this project, for example Cortec MCI-2000 which is currently being used by HDOT harbors division without local tests to verify its performance with concretes based on Hawaiian aggregates.

3. Longer term field monitoring of successful admixtures. The current study has identified which corrosion inhibiting admixtures appear to work and which do not. However, after 10 years of exposure (on only 5 years of funding), a number of the specimens with fly ash, silica fume, and DCI or CNI, have not started to corrode. Ideally, specimens should be kept in the field exposure until corrosion initiates to determine the true performance of these admixtures.

4. The specimens in this study consisted of uncracked concrete, at least until corrosion initiated cracks. This is unrealistic for most in-place concrete which will crack due to shrinkage, temperature, construction loads, etc. In order to evaluate the successful admixtures for true field conditions, it is necessary to fabricate specimens that simulate the types of cracks most common in field construction. These specimens would then be exposed to the same tidal zone conditions as the original un-cracked specimens to determine whether or not the admixtures can still delay the onset of corrosion.

5. For the current study, all specimens were placed in the tidal zone. This meant there were no panels that were in a coastal environment, but not in the tidal zone, and no specimens that were completely submerged. The tidal zone is known to be the most corrosive environment, hence it was chosen for this study. However, most harbor facilities and coastal structures are predominantly out of the water, or continuously submerged, both of which are less corrosive environments. A better understanding of the performance of the successful admixtures in these environments is also important for future coastal construction. It would be uneconomical to design all harbor and coastal structures assuming the worst case of tidal zone exposure.

 

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Publications

Appendix C contains copies of the following conference publications based on various aspects or stages of this project.

1. Robertson, I.N., Improving Concrete Durability through the use of Corrosion Inhibitors, 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, Cape Town, South Africa, September 3-5, 2012.

2. Robertson, I.N., Prediction of Chloride Ingress into Concrete in a Marine Environment, SCSS 2012, Strategies for Sustainable Concrete Structures, Aix-en-Provence, France, May 29 – June 1, 2012.

3. Robertson, I.N., and Newtson, C., Improving Concrete Durability through use of Corrosion Inhibitors, Proceedings of the IABSE-IASS 2011 Symposium, London, England, Sept. 20-23, 2011.

4. Robertson, I.N., and Newtson, C., Performance of Corrosion Inhibitors in Concrete Exposed to Marine Environment, Proceedings of the International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR2008, Cape Town, South Africa, Nov. 24-26, 2008.

In addition to presentations at the above conferences, this project has also been presented at the following seminars and workshops:

1. Concrete Durability – Hawaii Study, CCPI Annual Meeting, Wailea, Maui, Oct. 7, 2011

2. Concrete Durability Enhancement through use of Corrosion Inhibitors, Hawaii DOT Harbors Division, Honolulu, Hawaii, Sept. 27, 2011

3. Concrete Durability Research, CCPI-SEAOH Convention, Waikiki, Honolulu, Oct. 16, 2009.

4. Improved Durability of Coastal Infrastructure Subjected to Corrosion, Research Seminar by Faculty, Saitama University, Saitama, Japan, July 30, 2009.

5. Update on corrosion studies and effects of Hurricane Katrina on engineered structures, Construction Specifications Institute seminar, Honolulu, Hawaii, August 21, 2007.

6. Corrosion of Cold-Formed Steel Framing and Concrete Reinforcing Steel, 2006 Pacific Building Trade Expo, Honolulu, Hawaii, October 24, 2006.

7. Concrete for Sustainable Construction, 37th Annual Meeting of the Cement and Concrete Products Industry of Hawaii, Ko Olina, Hawaii, October 2001.

 

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TABLE OF CONTENTS

1  INTRODUCTION ................................................................................................................................ 1 

1.1  Background ................................................................................................................................. 1 

1.2  Objective....................................................................................................................................... 2 

1.3  Scope .............................................................................................................................................. 3 

2  BACKGROUND AND LITERATURE REVIEW ......................................................................... 5 

2.1  Introduction ................................................................................................................................ 5 

2.2  Mechanisms of Concrete Corrosion.................................................................................. 5 

2.3  The Role of Chloride Ions in Corrosion ........................................................................... 6 

2.4  Initiation of Corrosion due to Chloride Ion Penetration ......................................... 7 

2.5  Chloride Concentration Tests ............................................................................................. 8 

2.6  Objectives for Corrosion Inhibiting Concrete Admixtures ..................................... 9 

2.6.1  Calcium Nitrite‐Based Corrosion Inhibitors ........................................................ 9 

2.6.2  Rheocrete 222+ ................................................................................................................ 9 

2.6.3  FerroGard 901 ............................................................................................................... 10 

2.6.4  Xypex Admix C‐2000 ................................................................................................... 10 

2.6.5  Latex‐Modifiers ............................................................................................................. 11 

2.6.6  Fly Ash ............................................................................................................................... 11 

2.6.7  Silica Fume ...................................................................................................................... 12 

2.6.8  Kryton KIM ...................................................................................................................... 12 

2.7  Overview of Life‐365 Service Life Prediction Software ........................................ 13 

2.7.1  Background to Life‐365 Service Life Prediction Software ......................... 13 

2.7.2  Mathematical Equations of Life‐365 Service Life Prediction Model ...... 14 

2.7.3  Assumptions and Limitations of Life‐365 Service Life Prediction Software ............................................................................................................................................ 16 

2.8  Summary ................................................................................................................................... 21 

3  EXPERIMENTAL PROCEDURES .............................................................................................. 23 

3.1  Introduction ............................................................................................................................. 23 

3.2  Mixtures Created by Previous Phases of Research ................................................. 23 

3.2.1  Control Mixtures ........................................................................................................... 23 

3.2.2  DCI Mixtures ................................................................................................................... 26 

3.2.3  Rheocrete CNI Mixtures............................................................................................. 28 

3.2.4  Rheocrete 222+ Mixtures ......................................................................................... 31 

3.2.5  FerroGard 901 Mixtures ............................................................................................ 34 

 

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3.2.6  Xypex Admix C‐2000 Mixture ................................................................................. 36 

3.2.7  Latex Modified Mixtures ........................................................................................... 38 

3.2.8  Fly Ash Mixtures ........................................................................................................... 40 

3.2.9  Silica Fume Mixtures ................................................................................................... 44 

3.2.10  Kryton KIM Mixtures .................................................................................................. 49 

3.3  Phase III Field Specimen Fabrications ......................................................................... 50 

3.3.1  Phase III Field Specimen Test Preparations ..................................................... 52 

3.4  Phase III & Phase IV Testing Procedures for Chemical Tests............................. 54 

3.4.1  Phase III Test for Chloride Concentrations for 2004 Samples ................. 54 

3.4.2  Phase III Test for Chloride Concentrations for 2006 Samples ................. 55 

3.4.3  Phase IV Test for Chloride Concentrations for 2008 Samples .................. 56 

3.5  Half‐cell Potential Tests ...................................................................................................... 56 

3.6  Life‐365 Corrosion Prediction Software Set Up ....................................................... 58 

3.6.1  Program Inputs ............................................................................................................. 58 

3.6.2  Program Outputs .......................................................................................................... 59 

3.7  Summary ................................................................................................................................... 60 

4  RESULTS OF FIELD PANELS AND LIFE‐365 PREDICTIONS ....................................... 61 

4.1  Introduction ............................................................................................................................. 61 

4.2  Life‐365 Comparisons ......................................................................................................... 61 

4.2.1  Concentrations and Predictions for Control Mixtures ................................. 62 

4.2.2  Concentrations and Predictions for DCI Mixtures ......................................... 67 

4.2.3  Concentrations and Predictions for Rheocrete CNI Mixtures ................... 69 

4.2.4  Concentrations and Predictions for Rheocrete 222+ Mixtures ................ 70 

4.2.5  Concentrations and Predictions for Fly Ash Mixtures ................................. 72 

4.2.6  Concentrations and Predictions for Silica Fume Mixtures ......................... 73 

4.3  Half‐cell Potentials ................................................................................................................ 75 

4.3.1  Half‐cell Results and Visual Observations for Control Panels .................. 75 

4.3.2  Half‐cell Results and Visual Observations for DCI Panels .......................... 79 

4.3.3  Half‐cell Results and Visual Observations for Rheocrete CNI Panels .... 82 

4.3.4  Half‐cell Results and Visual Observations for Rheocrete 222+ Panels . 85 

4.3.5  Half‐cell Results and Visual Observations for Fly Ash Panels ................... 88 

4.3.6  Half‐cell Results and Visual Observations for Silica Fume Panels .......... 91 

4.4  Summary ................................................................................................................................... 95 

5  CONCLUSIONS ................................................................................................................................ 97 

 

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6  RESEARCH PROJECT PUBLICATIONS ................................................................................... 99 

6.1  Research Reports (Copies available online) .............................................................. 99 

6.2  Conference Publications (Copies provided in Appendix C) ................................ 99 

6.3  Conference and Seminar Presentations ................................................................... 100 

7  OTHER REFERENCES ............................................................................................................... 101 

8  APPENDIX B .................................................................................................................................. 103 

9  APPENDIX B .................................................................................................................................. 135 

10  APPENDIX C .................................................................................................................................. 159 

 

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LIST OF TABLES

Table E‐1‐1: Results of half‐cell and visual inspection of field corrosion specimens .. 5 Table E‐2: Life‐365 default and proposed parameters. ............................................................. 6 Table 2‐1: Maximum Chloride Ion Content in Concrete (Taken from ACI 318‐08, ACI 222R‐01, ACI 201.2R‐01) ........................................................................................................................ 8 Table 2‐2: Default Build‐up Rates and Maximum Surface Concentration for Marine Environments in Life‐365 (Life‐365, 2012) ................................................................................ 17 Table 2‐3: Average Published Values for m, Various Concrete Mixtures (Life‐365, 2012) ............................................................................................................................................................ 19 Table 2‐4: Effects of Slag and Fly Ash on Diffusion Coefficients in Life‐365 (Life‐365, 2012) ............................................................................................................................................................ 20 Table 2‐5: Effects of CNI on Threshold Values in Life‐365 (Life‐365, 2012) ................ 21 Table 3‐1: Phase II Kapaa Control Mixtures ................................................................................ 24 Table 3‐2: Phase II Halawa Control Mixtures ............................................................................. 25 Table 3‐3: Phase III Control Mixtures ............................................................................................ 26 Table 3‐4: Phase II DCI Mixtures ...................................................................................................... 27 Table 3‐5: Phase III DCI Mixtures .................................................................................................... 28 Table 3‐6: Phase II Kapaa Rheocrete CNI Mixtures .................................................................. 29 Table 3‐7: Phase II Halawa Rheocrete CNI Mixtures ............................................................... 30 Table 3‐8: Phase III Rheocrete CNI Mixtures .............................................................................. 31 Table 3‐9: Phase II Kapaa Rheocrete 222+ Mixtures .............................................................. 32 Table 3‐10: Phase II Halawa Rheocrete 222+ Mixtures ......................................................... 33 Table 3‐11: Phase III Rheocrete 222+ Mixtures ........................................................................ 34 Table 3‐12: Phase II Kapaa FerroGard 901 Mixtures .............................................................. 35 Table 3‐13: Phase III FerroGard 901 Mixtures .......................................................................... 36 Table 3‐14: Phase II Kapaa Xypex Admix C‐2000 Mixtures ................................................. 37 Table 3‐15: Phase III Xypex Admix C‐2000 Mixture ................................................................ 38 Table 3‐16: Phase II Kapaa Latex‐Modified Mixtures ............................................................. 39 Table 3‐17: Phase III Latex‐Modified Mixture ............................................................................ 40 Table 3‐18: Fly Ash Chemical Composition (Pham and Newtson 2001) ........................ 40 Table 3‐19: Phase II Kapaa Fly Ash Mixtures .............................................................................. 42 Table 3‐20: Phase II Halawa Fly Ash Mixtures ........................................................................... 43 Table 3‐21: Phase III Fly Ash Mixtures .......................................................................................... 44 Table 3‐22: Phase II Kapaa Silica Fume Mixtures ..................................................................... 46 Table 3‐23: Phase II Halawa Force 10,000D Silica Fume Mixtures ................................... 47 Table 3‐24: Phase II Halawa Rheomac SF100 Mixtures ......................................................... 48 Table 3‐25: Phase III Silica Fume Mixtures ................................................................................. 49 Table 3‐26: Phase III Kryton KIM Mixture ................................................................................... 50 Table 3‐27: Average Monthly Honolulu Harbor Temperatures used for Life‐365 Predictions. ................................................................................................................................................ 59 Table 4‐1: Default and Adjusted Input Values for Control Panels 1 and 2 ..................... 62 Table 4‐2: Default and Adjusted Input Values for Control Panel 7 .................................... 65 Table 4‐3: Default and Adjusted Input Values for all DCI Panels ....................................... 67 

 

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Table 4‐4: Default and Adjusted Input Values for all Rheocrete CNI Panels ................. 69 Table 4‐5: Default and Adjusted Input Values for all Rheocrete 222+ Panels .............. 70 Table 4‐6: Default and Adjusted Input Values for all Fly Ash Panels ............................... 72 Table 4‐7: Default and Adjusted Input Values for all Silica Fume Panels ....................... 73 Table 4‐8: Corrosion Ranges for Half‐cell Potential Test Results (V vs. CSE) ............... 75 

 

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LIST OF FIGURES

Figure 2‐1: Electrochemical process of corrosion (Concrete Technology, 2011). ......... 5 Figure 2‐2: Relationship Between D28 and w/cm (Life‐365, 2012) ................................... 18 Figure 2‐3: Effect of Silica Fume on DSF (Life‐365, 2012) ...................................................... 19 Figure 2‐4: Effects of Fly Ash and Slag on Dt (Life‐365, 2012) ............................................ 20 Figure 3‐1: Typical Phase III Field Specimen Geometry (Uno et al. 2004) .................... 51 Figure 3‐2: Typical Phase III Panel Reinforcing Steel Layout (Uno et al. 2004) .......... 52 Figure 3‐3: Location of Field Panels at Pier 38 Honolulu Harbor ...................................... 53 Figure 3‐4: Placement of the Phase III Field Panels at Pier 38 (Uno et al. 2004) ........ 54 Figure 3‐5: Phase III Chloride Sample Depths by Drill Method. ......................................... 55 Figure 3‐6: Phase III & Phase IV Chloride Sample Depths by Core Method. ................. 56 Figure 3‐7: Electrical Connection to Rebar for Half‐cell Tests ............................................ 57 Figure 3‐8: Half‐cell Test Locations ................................................................................................ 57 Figure 4‐1: Life‐365 predictions for 2004 Control Panel 1. ................................................. 62 Figure 4‐2: Life‐365 predictions for 2006 Control Panel 1. ................................................. 63 Figure 4‐3: Life‐365 predictions for 2008 Control Panel 1. ................................................. 63 Figure 4‐4: Life‐365 predictions for 2004 Control Panel 2. ................................................. 64 Figure 4‐5: Life‐365 predictions for 2006 Control Panel 2. ................................................. 64 Figure 4‐6: Life‐365 predictions for 2008 Control Panel 2. ................................................. 65 Figure 4‐7: Life‐365 predictions for 2004 Control Panel 7. ................................................. 66 Figure 4‐8: Life‐365 predictions for 2006 Control Panel 7. ................................................. 66 Figure 4‐9: Life‐365 predictions for 2008 Control Panel 7. ................................................. 67 Figure 4‐10: Life‐365 predictions for 2006 DCI Panel 3. ....................................................... 68 Figure 4‐11: Life‐365 predictions for 2006 DCI Panel 4. ....................................................... 68 Figure 4‐12: Life‐365 predictions for 2008 Rheocrete CNI Panel 5A. ............................. 69 Figure 4‐13: Life‐365 predictions for 2008 Rheocrete CNI Panel 6. ................................ 70 Figure 4‐14: Life‐365 predictions for 2006 Rheocrete 222+ Panel 16. ........................... 71 Figure 4‐15: Life‐365 predictions for 2006 Rheocrete 222+ Panel 17. ........................... 71 Figure 4‐16: Life‐365 predictions for 2008 Fly Ash Panel 11. ............................................ 72 Figure 4‐17: Life‐365 predictions for 2006 Fly Ash Panel 12. ............................................ 73 Figure 4‐18: Life‐365 predictions for 2008 Silica Fume Panel 8. ....................................... 74 Figure 4‐19: Life‐365 predictions for 2006 Silica Fume Panel 10. .................................... 74 Figure 4‐20: Half‐cell Potential Tests for Control Panel 1. .................................................... 76 Figure 4‐21: Final Visual Observations for Control Panel 1. ................................................ 76 Figure 4‐22: Half‐cell Potential Tests for Control Panel 2. .................................................... 77 Figure 4‐23: Final Visual Observations for Control Panel 2. ................................................ 77 Figure 4‐24: Half‐cell Potential Tests for Control Panel 7. .................................................... 78 Figure 4‐25: Final Visual Observations for Control Panel 7. ................................................ 78 Figure 4‐26: Half‐cell Potential Tests for DCI Panel 3. ............................................................ 80 Figure 4‐27: Final Visual Observations for DCI Panel 3. ........................................................ 80 Figure 4‐28: Half‐cell Potential Tests for DCI Panel 4. ............................................................ 81 Figure 4‐29: Final Visual Observations for DCI Panel 4. ........................................................ 81 Figure 4‐30: Half‐cell Potential Tests for Rheocrete CNI Panel 5A. .................................. 83 

 

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Figure 4‐31: Final Visual Observations for Rheocrete CNI Panel 5A. ............................... 83 Figure 4‐32: Half‐cell Potential Tests for Rheocrete CNI Panel 6. ..................................... 84 Figure 4‐33: Final Visual Observations for Rheocrete CNI Panel 6. .................................. 84 Figure 4‐34: Half‐cell Potential Tests for Rheocrete 222+ Panel 16. ............................... 86 Figure 4‐35: Final Visual Observations for Rheocrete 222+ Panel 16. ............................ 86 Figure 4‐36: Half‐cell Potential Tests for Rheocrete 222+ Panel 17. ............................... 87 Figure 4‐37: Final Visual Observations for Rheocrete 222+ Panel 17. ............................ 87 Figure 4‐38: Half‐cell Potential Tests for Fly Ash Panel 11. ................................................. 89 Figure 4‐39: Final Visual Observations for Fly Ash Panel 11. .............................................. 89 Figure 4‐40: Half‐cell Potential Tests for Fly Ash Panel 12. ................................................. 90 Figure 4‐41: Final Visual Observations for Fly Ash Panel 12. .............................................. 90 Figure 4‐42: Half‐cell Potential Tests for Silica Fume Panel 8. ........................................... 92 Figure 4‐43: Final Visual Observations for Silica Fume Panel 8. ........................................ 92 Figure 4‐44: Half‐cell Potential Tests for Silica Fume Panel 9. ........................................... 93 Figure 4‐45: Final Visual Observations for Silica Fume Panel 9. ........................................ 93 Figure 4‐46: Half‐cell Potential Tests for Silica Fume Panel 10. ......................................... 94 Figure 4‐47: Final Visual Observations for Silica Fume Panel 10. ..................................... 94 

 

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1 INTRODUCTION

1.1 Background

Reinforced concrete is one of the most widely used building materials found in modern structures due to its abundance of materials, speed and versatility in construction, strength, durability, and relatively long life spans. However, corrosion of the reinforcing used in concrete structures is of utmost importance to the life cycles and long-term durability of these structures especially to those areas exposed to marine environments. According to a study done by CC Technologies Laboratories, Inc. from 1999 to 2001 (sponsored by the Federal Highway Administration and the National Association of Corrosion Engineers), the cost of corrosion in the U.S. was estimated at $276 billion, which is approximately 3.1% of the United States’ Gross Domestic Product (Koch et al. 2001). These statistics clearly indicate the need for corrosion protection of infrastructure that will prove to not only be cost effective at the onset of construction, but effective in providing longer life cycles.

Several methods have been developed to inhibit the rate of corrosion in reinforced concrete structures. Included in these methods is the use of protective coatings (such as epoxy coatings), corrosion resistant alloys (such as stainless steel), corrosion inhibiting admixtures, engineered plastics and polymers (such as FRP), and cathodic and anodic protection. The use of concrete inhibiting admixtures is considered one of the more cost effective solutions to the corrosion process (Koch et al. 2001) and is the focus of this research.

This research project began with Phase I, a study performed by Bola and Newtson (2000). Eight sites within marine environments on Oahu were selected and samples were taken from the concrete piers around the selected sites to evaluate the effectiveness of the corrosion-inhibiting admixtures that were added at the time the piers were constructed. The on-site tests that were performed on these piers included pH, permeability, half-cell potential, linear polarization, resistance and resistivity. Core samples were also taken to measure the mechanical properties and chloride contents at various depths from the surfaces of each test specimen.

Phase II of this project was performed by Pham and Newtson (2001), Okunaga, Robertson and Newtson (2005), and Kakuda, Robertson and Newtson (2005). These studies were performed to evaluate the concrete properties of mixtures that included corrosion inhibiting admixtures and pozzolanic materials. Various concrete mixtures with corrosion inhibiting admixtures were included in the construction of 660 specimen in the structures laboratory at UH Manoa. These specimens were introduced to an accelerated cyclic wetting and drying pattern in which a salt-water solution was used to represent a marine environment. Half-cell potential, linear polarization, and resistivity were measured after each cycle. Upon corrosion failure, chloride concentration, pH, and air permeability tests were performed on each specimen to determine the effects of the corrosion inhibiting admixtures.

 

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Phase III for this project was performed by Uno, Robertson and Newtson (2004) and Cheng and Robertson (2006). Within this phase of research, twenty-five reinforced concrete field panels were constructed and placed into the ocean at Honolulu Harbor’s Pier 38. The field panels included the corrosion inhibiting admixtures used in Phase II of this study. Half-cell potential and air permeability tests were performed in the field. Core samples were taken from these panels and used to measure chloride content and pH at various depths from the surface. These panels were monitored intermittently from the time of first placement in 2002 and 2003 to April 2012. The first evaluation period was performed in 2004 by Uno et al. (2004). The second evaluation period was performed in 2006 by Cheng and Robertson (2006). Many of the samples from the 2008 evaluation period have been collected and are included in this report. The field panels have been removed from the harbor after 10 years of exposure. The original contract only called for 5 years exposure, but no visible signs of corrosion had been observed at that time, so monitoring was continued till a number of panels showed signs of corrosion. Final samples and testing for the Phase III field panels is still in progress in the structures lab in Holmes Hall and these final evaluations will not be included in this report. The Phase II laboratory samples are also still in the process of being sampled and will not be considered in this report.

This research project will be considered as Phase IV of the overall corrosion and concrete durability study performed by the students and under the direction of faculty in the Civil and Environmental Engineering Department at the University of Hawaii at Manoa.

1.2 Objective

The objective behind performing this research project is to investigate the effects of chloride ions in concrete structures specifically exposed to marine environments. The extent of this research will be limited to concrete structures that use corrosion-inhibiting admixtures and pozzolanic materials as a means to retard the corrosion process in concrete. The concrete admixtures used for the various phases of this research project included DAREX Corrosion Inhibitor (DCI), Rheocrete CNI, Rheocrete 222+, FerroGard 901, Xypex Admix C-2000, latex modifiers, silica fume, fly ash, and Kryton KIM. Data from concrete specimens in the controlled laboratory environment of Phase II has not been completely collected and will not be considered for this Phase IV study. All of the data from the field panel concrete specimens collected in 2004, 2006 and many in 2008 from the Phase III studies have been collected and are used for this study. Such data used for comparison includes the specimen’s chloride ion content at various depths through the specimen. Finally, comparisons of the collected data were made between the field specimens to that of calculated predictions made from the computer program Life-365. This program is currently being introduced and used in the industry for service life predictions for concrete structures to assess the use of different means and methods to decelerate the corrosion process including the use of corrosion-inhibiting admixtures. The evaluations and comparisons of the concrete admixtures for this Phase IV study were limited to DAREX Corrosion Inhibitor (DCI), Rheocrete CNI, Rheocrete 222+, silica fume and fly ash as the Life-365 software is limited to these admixtures. Evaluations of the predicted calculations were made so that realistic adjustments and parameters can be

 

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imposed on the computer software to improve correlations between data collected and software output for future design use.

1.3 Scope

This report outlines the updated results and conclusions of the research project from Phases II and III. Chapter 2 provides a literature review of information on the mechanisms of corrosion, the influences of chlorides on corrosion, chloride penetrations in concrete, and the objectives for corrosion protection of reinforcing in concrete from the different concrete admixtures. A background of assumptions, limitations and mathematical methodologies of the computer software Life-365 is also presented in Chapter 2. Chapter 3 describes the fabrication of the Phase III field panel specimens used in this study as well as the experimental procedures performed on each specimen for the chloride chemical tests. The Life-365 software set-up, inputs and outputs are also described. Chapter 4 provides a comparison of chloride concentration results between Phase III field specimen results to that of the prediction software Life-365. Recommendations are also made on improving the prediction software correlations. Finally, Chapter 5 provides a summary of the entire research and discusses the conclusions to this study.

 

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2 BACKGROUND AND LITERATURE REVIEW

2.1 Introduction

The corrosion of metals, especially including that of reinforcing steel, has been a growing concern for structures due to the increase in occurrences and the costs of repairs. The first observances of corrosion of reinforcing steel in concrete structures included those found within marine environments (ACI Committee 222 2001). This chapter describes the basic theory and mechanisms that initiate the corrosion process, the influence of chloride ions on corrosion, chloride penetration in concrete, and the corrosion inhibiting effects of concrete admixtures. A brief overview of the tests used to determine the chloride concentration is included. A discussion on the mathematical prediction models and assumptions are also presented for the software program Life-365.

2.2 Mechanisms of Concrete Corrosion

Corrosion can be defined as the oxidative deterioration of a metal such as the conversion of iron to rust (McMurry and Fay 2001). The corrosion process of iron is noted to be a complex chemical reaction that requires both oxygen and moisture (i.e. water) be present (Brady and Senese 2004). Corrosion is known to be an electrochemical process that involves the flow of electrons and ions between the anode and cathode through a medium known as an electrolyte. In the case of reinforced concrete, the concrete (the pore water therein) acts as the electrolyte. The iron in the reinforcing steel dissolves (oxidizes) in the anodic regions releasing electrons through the metal and travels to the cathodic regions where the oxygen is reduced (Brady and Senese 2004). Figure 2-1 illustrates the complete electrochemical process for corrosion of iron in reinforcing steel.

Figure 2-1: Electrochemical process of corrosion (Concrete Technology, 2011).

 

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When the iron in the reinforcing steel oxidizes at the anode, the metallic form of iron (Fe) will dissolve into ferrous ions and release electrons in the presence of water as shown in Equation 2.1.

Reaction at the Anode Region: eFeFe 22 (Eqn. 2.1)

The electrons that are released at the anode regions after the iron is oxidized flow through the reinforcing steel to the areas where the iron is exposed to oxygen (Brady and Senese 2004). This area is known as the cathode region and is where the oxygen accepts the negatively charged electrons (i.e. the oxygen is reduced). This reaction of oxygen and water forms hydroxyl ions (OH-) as indicated in Equation 2.2.

Reaction at the Cathode Region: 12 2 2 (Eqn. 2.2)

The iron (II) ions (Fe2+) that are formed at the anode regions diffuse within the water and combine with the hydroxyl ions (OH-). This combination forms the soluble solution termed ferrous hydroxide, Fe(OH)2, and is shown in Equation 2.3.

2 (Eqn. 2.3)

When the iron (II) (Fe2+) ions are further oxidized to iron (III) (Fe3+) ions by the O2, the resulting combination gives Fe(OH)3 (known as hydrated oxide), which is the red-brown material commonly called rust (McMurry and Fay 2001).

2.3 The Role of Chloride Ions in Corrosion

The intrusion of chloride ions in reinforced concrete is considered the most important factor of corrosion (Smith and Virmani 2000). The involvement of chloride ions on metal corrosion in concrete is the most extensively documented reinforced concrete contaminants (Concrete Technology 2011). Corrosion in reinforced concrete can occur without the presence of chloride ions (e.g. carbonation-induced corrosion or acid attack), but the most common influence on corrosion is due to inclusion of chloride ions (ACI Committee 222 2001). Chlorides can be introduced in the concrete structures by means of the mix ingredients including aggregates and water, chloride-containing admixtures or the exposure to environments that include the presence of chlorides. Of these factors, the most common influence of chlorides on reinforced concrete structures come from the environments to which the concrete is exposed including areas that use deicing salts or marine environments (Li and Sagues 2001).

Concrete provides a naturally high-alkaline environment (pH typically between 12 to 13), which creates a thin passive oxide layer around the reinforcing steel and promotes a corrosion barrier around the steel. However, this passive film does not completely stop corrosion, but reduces the corrosion rate to an insignificant level (ACI Committee 222 2001). The typical corrosion rates of reinforcing steel in concrete is around 0.1 μm per

year and without the benefit of the passive layer present in concrete, the corrosion rate of the steel would increase by one thousand times (ACI Committee 222 2001). Once the alkalinity of the concrete is reduced, the passivity layer around the reinforcing steel is depassivated (or diminished) and increases the susceptibility of corrosion.

 

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A full comprehension of the mechanisms that depassivate the natural protective passive layer around reinforcing steel in concrete has not been reached. However, many theories have emerged on how the presence of chloride ions affects this passive layer.

One such theory is the Oxide Film Theory, which simply attributes the depassivation of the oxide layer to attack from chloride ions. Chloride ions are believed to penetrate the passive oxide layer at better rates than other ions (Concrete Technology 2011). With the passive layer removed, the steel is much more susceptible to corrosion. Another theory is the Absorption Theory. This theory attributes the corrosion mechanism to direct attack from chloride ions as these ions are absorbed into the surface of the reinforcing steel. The chloride ions compete with the hydroxyl ions and promote hydration of the ferrous ions, which continues the dissolution process (Uno et al. 2004). According to the a report funded by the U.S. Department of Transportation and Federal Highway Administration (Smith and Virmani 2000), a theory in which the chloride ions are considered to act as a catalyst is termed the Transitory Complex Theory. In this theory, the chloride ions combine with the ferrous ions and a soluble iron-chloride solution is formed. This solution is said to diffuse away from the anode and in turn ferrous hydroxide [Fe(OH)2] is formed. Upon this formation of ferrous hydroxide, the chloride ions are freed up upon the breakdown of the iron-chloride complex and are reused to continue the diffusion process.

All differences in the theories aside, the resulting effects of corrosion on reinforcing steel in concrete include deterioration of the steel bar cross section, induced stresses, and increased volume around the steel which can lead to cracks, delaminations and spalls in the concrete. The original volume that the reinforcing bars occupy may increase three to six times due to the corrosion process (Smith and Virmani 2000).

2.4 Initiation of Corrosion due to Chloride Ion Penetration

The first step in the corrosion process is the penetration of chlorides through the concrete surface. Next, the breakdown of the passive layer around the reinforcing steel must take place prior to activating the corrosion initiation process. The initiation of reinforcing steel corrosion in concrete is most commonly caused by the presence of chloride ions (ACI Committee 222 2001). According to Vector Corrosion Technologies (2009), the initiation of corrosion occurs at chloride thresholds around 1.0 to 1.4 pounds of water soluble chloride ions [ ] at the level of the reinforcing steel per cubic yard of concrete. The U.S. DOT and FHWA (Smith and Virmani 2000) report that the general minimum corrosion chloride threshold to be 1.2 pounds of water soluble chloride ions, but that selecting a single value for these threshold limits may not be accurate due to variable factors. Chloride diffusion rates are affected by numerous factors of which water-to-cement ratios, concrete composition, humidity, temperature, and pH are among some. Another diffusion rate factor in concrete structures is with those structures that are subjected to water saturated environments such as marine environments. Concrete structures that are completely submerged under water have a slower oxygen diffusion rate as the oxygen must first diffuse through the porewater of the concrete whereas those structures above the surface that are dry are able to simply penetrate through the pores (Smith and Virmani 2000). Recall that the availability of oxygen and water are factors that influence the corrosion rate. The alternating wetting and drying pattern that occurs

 

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on concrete structures (such as at the tidal zones of piers) is reported to accelerate the corrosion process (Smith and Virmani 2000).

2.5 Chloride Concentration Tests

There are three different commonly used analytical methods used for determining the chloride ion content in hardened concrete. The first of these is called the water-soluble chloride method, which measures the amount of chloride ions that are extractable in water. The other two methods are referred to as the acid-soluble chloride method and the total chloride method and commonly use nitric acid as an extraction liquid. The acid-soluble chloride is often, but not necessarily, considered equal to the total chloride (ACI Committee 222 2001). Each test method involves collecting concrete powder samples from the specimens and dissolving the samples into the extraction liquids (either water or nitric acid depending on the selected method) to determine the amount of dissolved chloride. The amount of chloride ions present found by either method is usually expressed as a percentage of cement content in the sample. The chloride limits for the water-soluble and acid-soluble test methods are determined between 28 to 42 days after initial construction of the concrete specimen. Table 2-1 lists the various maximum water-soluble and acid-soluble chloride ion content values in concrete reported by the ACI 318 Building Code (2008), ACI Committee 222 (2001) and ACI Committee 201 (2001).

Table 2-1: Maximum Chloride Ion Content in Concrete (Taken from ACI 318-08, ACI 222R-01, ACI 201.2R-01)

Category

Chloride limit for new construction

(% by mass of cement)

Test method

Acid-soluble Water-soluble

ACI 222R-01 ACI 318-08 ACI 201.2R-01 ACI 222R-01

Prestressed concrete

0.08 0.06 0.06 0.06

Reinforced concrete in wet

conditions 0.10 0.15 0.10 0.08

Reinforced concrete in dry

conditions 0.20 0.30 0.15 0.15

Currently, a common maximum chloride threshold value of 0.15% water-soluble or 0.20% acid-soluble chloride ion content, measured by mass of cement, is recommended by ACI Committee 222 (2001) and ACI Committee 201 (2001). These threshold values were also confirmed by laboratory and field tests performed by the Federal Highway Administration, which indicated that the chloride threshold values (0.15% water-soluble or 0.20% acid-soluble chloride ion content) are sufficient in some cases to initiate

 

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corrosion of embedded mild steel found within concrete structures exposed to chlorides while in service (ACI Committee 222 2001). The maximum chloride limits of ACI Committees 222 and 201 listed in Table 2-1 are noted to differ from those values reported by the ACI 318 Building Code (2008). The ACI Committee 222 (2001) reports that it has taken a more conservative approach due to the serious consequences of corrosion, the conflicting data on corrosion-threshold values, and the difficulty of defining the service environment throughout the life of a structure.

2.6 Objectives for Corrosion Inhibiting Concrete Admixtures

DAREX Corrosion Inhibitor (DCI), Rheocrete CNI, Rheocrete 222+, FerroGard 901, Xypex Admix C-2000, latex modifier, silica fume, fly ash, and Kryton KIM were the concrete admixtures used in the previous phases of this research project. This section will provide a brief overview of the concrete admixtures used in Phase II and Phase III of this study and their intended effects on concrete properties.

2.6.1 Calcium Nitrite-Based Corrosion Inhibitors

Two common functions of calcium nitrite, when used as a concrete admixture, are being used as a corrosion inhibitor and a concrete set time accelerator that does not contain chlorides. DCI Corrosion Inhibitor, produced by W.R. Grace & Co.-Conn., and Rheocrete CNI, a product of BASF Construction Chemicals, LLC., are both calcium nitrite based corrosion inhibitors that contain a minimum of 30% calcium nitrite by mass. These concrete admixtures are primarily used for prevention of chloride attack on reinforcing steel. Both manufacturers recommend the use of these calcium nitrite corrosion-inhibiting products in concrete applications where exposure to chlorides from de-icing salts or marine environments are likely to occur.

Calcium nitrite chemically reacts with the reinforcing steel by repassivating the steel surface, which continues to provide a corrosion barrier against chloride ion attacks. The chemical reaction that occurs between the nitrite ions and ferrous ions creates a more stable form of ferric ions that are less susceptible to corrosion (BASF Construction Chemicals 2007). These ferric ions are in the creation of ferric oxide, Fe2O3, which enhances the passivation layer around the steel surface so much so that calcium nitrite type admixtures are also called anodic inhibitors (Pham and Newtson 2001). However, the nitrite ions must compete with the amount of chloride ions present within the concrete in reaction with the ferrous ions in order to be effective as a corrosion inhibitor (Uno et al. 2004). Sufficient quantities of the calcium nitrite based admixtures must be added in comparison with the anticipated chloride ion content that may exist in order to maintain control of the corrosion process within the concrete matrix (W.R. Grace & Co.-Conn. 2007). According to the Phase I study performed by Bola and Newtson (2000), the sample concrete cores taken from the field evaluations indicated that higher dosages of calcium nitrite provided the reinforcing steel with a significantly greater protection than lower dosages (4.0 to 4.5 gal/yd3 compared to 2.5 gal/yd3 respectively).

2.6.2 Rheocrete 222+

Rheocrete 222+, a product of BASF Construction Chemicals, LLC., is an organic corrosion-inhibiting admixture (a combination of amines and esters) that provides two

 

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different mechanisms of corrosion protection. The first mechanism of protection that is provided by this admixture is a waterproofing type inhibition within the concrete matrix. The rate of chloride and moisture penetration into the concrete is reduced due to the admixture lining the pores of the concrete matrix creating a barrier against these components needed for the corrosion process.

The second mechanism of corrosion protection that organic based corrosion inhibiting admixtures offer is that of creating a protective film around the reinforcing steel. Unlike other admixtures that simply repassivate the concrete matrix around the reinforcing steel, Rheocrete 222+ provides a secondary corrosion protection by adsorbing onto the steel. This adsorption onto the steel creates a protective film and further slows the penetrations of chlorides, moisture, and oxygen that would react with the steel in the corrosion process.

Rheocrete 222+, being an organic based corrosion inhibitor, does not have to compete against chloride ion concentrations within the concrete as other corrosion inhibiting admixtures such as calcium nitrite based admixtures (Pham and Newtson 2001). The typical dosage for Rheocrete 222+ within concrete mixtures is 1 gal/yd3. This amount is recommended by the manufacturer to be used in a single dosage so that prediction of the corrosive environment and chloride exposure of the structure is not necessary (BASF Construction Chemicals 2007).

2.6.3 FerroGard 901

FerroGard 901 is a liquid corrosion-inhibiting admixture produced by Sika Corporation recommended for use in corrosive environments. FerroGard 901 consists of a combination of aminoalcohols, and organic and inorganic inhibitors. Similar to the mechanisms described for Rheocrete 222+, FerroGard 901 is a dual action corrosion inhibitor. The first such corrosion action is the formation of a physical protective barrier against chloride ions and other similar substances. The second active mechanism included in FerroGard 901 is the adsorption onto the reinforcing steel surface, which the manufacturer claims is due to the high vapor pressure of the product. Due to this bond between FerroGard 901 and the reinforcing steel, the manufacturer reports that chloride ions are displaced from the metal surface, which in turn provides protection against chloride induced corrosion.

Recommended dosages of FerroGard 901 range from 2 gal/yd3 to 3 gal/yd3 depending on the severity of the chloride and marine exposure. The manufacturer claims that the rates of corrosion are delayed and reduced by 65% versus the control specimens of 400 days (Sika 2008). FerroGard 901 is also reported to be able to penetrate concrete specimens 3 inches in 28 days for those applications including overlays or adjoining substrates.

2.6.4 Xypex Admix C-2000

Xypex Admix C-2000, manufactured by Xypex Chemical Corporation, is a chemical treatment type concrete admixture consisting of Portland cement, very fine treated silica sand, and other active proprietary chemicals. Xypex Admix C-2000 is used for waterproofing, protection and improvement of concrete and is therefore recommended for concrete structures primarily involving extreme hydrostatic pressure containment (e.g.

 

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reservoirs) and chemical attack resistance (e.g. waste water treatment plants). The active ingredients in the Xypex Admix C-2000 react with the concrete and by-products of cement hydration at the time of batching to start a catalytic reaction, which creates a non-soluble crystalline formation within the pores and capillary tracts of the concrete matrix (Xypex Chemical Corporation 2004). The resulting formation creates a permanent seal against water or other liquids as well as a protection from harsh environmental conditions that would otherwise cause deterioration. In the case of chloride infiltration, one could conclude that Xypex Admix C-2000 would simply act as a sealant that prevents penetration of chloride ions through the less permeable concrete matrix thus protecting the reinforcing steel from chloride-induced corrosion.

2.6.5 Latex-Modifiers

Latex is a dispersion of organic polymer particles in water (Diamond and Sheng 1989). The addition of latex to conventional concrete is known as latex-modified concrete. Latex admixtures modify the pore structure within the concrete and reduce the permeability, which in turn increases the corrosion capabilities of the concrete (Pham and Newtson 2001). When added to concrete, latex forms thread-like bridges across microcracks that typically occur in conventional concrete resulting in higher flexural and tensile strengths and greater fracture-toughness (Diamond and Sheng 1989). In addition to the reduced permeability of latex-modified concrete, the reduction of cracking in the concrete structure also increases the corrosion resisting capabilities of the concrete (Uno et al. 2004).

2.6.6 Fly Ash

Fly ash is one of the most commonly added extra ingredients in concrete and is classified as a pozzolan, which is a compound that reacts with the lime found in concrete to form a hard paste that holds the aggregate together (Paradise et al. 2003). Fly ash is a synthetic pozzolan, which is created from the by-products of the combustion of ground or powdered coal removed from electric power generating plant exhaust gases. Fly ash is primarily silicate glass containing silica, alumina, iron, calcium and other minor ingredients including magnesium, sulfur, sodium, potassium, and carbon (Uno et al. 2004). Some of the benefits of including fly ash admixtures in concrete include improved workability, reduced segregation, bleeding, heat evolution and permeability, inhibiting alkali-aggregate reaction, and enhanced sulfate resistance (Federal Highway Administration 2011).

The fly ash particles are solid spheres that are typically finer than cement. On average, these fly ash spherical particles are less than 0.8x10-3 inches (20 m) in diameter (Pham and Newtson 2001). When fly ash is included in concrete mixtures, the density of the concrete is increased due to the voids in the concrete matrix being filled, consequently lowering the potential for corrosion damage as chloride permeability is reduced (Uno et al. 2004). Also due to the decrease in voids, fly ash increases the long-term concrete compressive strength.

The two major classes of fly ash are Class F and Class C, specified in ASTM C 618. In general, Class C fly ash has cementitious properties due to free lime in the concrete in addition to pozzolanic properties and Class F rarely has cementitious properties when solely mixed with water (Federal Highway Administration 2011). Class F fly ash

 

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typically has a lower calcium content with a carbon content less than 5%, whereas Class C fly ash has a higher calcium content with a carbon content less than 2% (Pham and Newtson 2001). Fly ash is considered low-quality when the carbon content is 10% or greater which can actually lead to increased permeability and interference with air-entrainment and is therefore regulated by the ASTM 618 standard building code limit of 6% carbon content along with industry preferences set at 3% or lower (Paradise et al. 2011).

2.6.7 Silica Fume

Silica fume is a pozzolanic material similar to fly ash. Silica fume is produced when the reduction of high-purity quartz with coal occurs in an electric arc furnace during the manufacturing process of silicon or ferrosilicon alloy (Pham and Newtson 2001). The diameter of the particle sizes for silica fume are 0.04x10-4 inches (0.1 m) on average, which is about 100 times smaller than the particles found in cement (Uno et al. 2004). Again similar to fly ash, the micro-sized particles of silica fume fill the voids of the concrete matrix resulting in an increase concrete density, permeability and strength.

The bonding between the constituents of the concrete matrix is also enhanced as silica fume reacts with water and calcium hydroxide Ca(OH)2, a product of the hydration reaction of water and cement, resulting in the formation of calcium silicate hydrate, CSH (Uno et al. 2004).

Two different types of silica fume were included in the previous phases of this study. The first type of silica fume used was Force 10,000D, produced by W.R. Grace & Co.-Conn. Force 10,000D is a high performance concrete admixture comprised of a dry densified microsilica powder that the manufacturer claims is designed to increase the compressive and flexural strengths of concrete as well as reduce the permeability and improve hydraulic abrasion resistance (W.R. Grace & Co.-Conn. 2010). The average dosage of Force 10,000D micosilica is between 2% and 15% by weight of cement. The addition of water reducers and superplasticisers are recommended due to the increased water demand when silica fume is added to the mixture.

This study also used Rheomac SF 100, a dry densified silica fume mineral admixture manufactured by BASF Construction Chemicals, LLC. The manufacturer claims that Rheomac SF 100 increases the service life of concrete structures as resistance to attack from environmental forces is added. Like the general properties of silica fume, Rheomac SF 100 reduces permeability by physically filling the voids within the concrete matrix and chemically reacting with the calcium silicate hydrate (CSH) found in concrete (BASF Construction Chemicals 2007). The manufacturer recommends adding a dosage of 5% to 15% of Rheomac SF 100 by weight of cement which is dependent on the desired strength or impermeability of the concrete. The manufacturer also recommends adding high-range water-reducing admixtures for workability.

2.6.8 Kryton KIM

KIM (Krystol Internal Membrane), produced by Kryton International Inc., is a dry powdered chemical admixture used for waterproofing concrete. The manufacturer states that KIM is a replacement for externally applied surface membranes used to protect against moisture transmission, chemical attack, and corrosion of reinforcing steel in

 

13 

concrete. KIM consists of millions of needle-like crystals that form from the reaction with un-hydrated cement particles found within the concrete mixture. The KIM crystals grow over long periods of time, which continue to fill the voids in the concrete matrix and thus prohibiting ingress of water and other waterborne contaminants (Kryton International 2011). The manufacturer states that one advantage to including KIM in concrete is the continued crystallization process that is triggered by the ingress of water where instances of cracking occur.

The recommended dosage of KIM in concrete is 2% by weight of cementitious materials to a maximum of 13.5 lbs/yd3. Testing reported by Kryton International Inc. indicates that concrete specimens that included KIM (2% by weight) were subjected to hydrostatic pressure and resulted in a maximum water penetration of less than 1/8 inch with no leakage or dampness. In other tests indicated by the manufacturer, the chloride permeability in the tested specimens containing KIM resulted in a reduction of 45%.

2.7 Overview of Life-365 Service Life Prediction Software

Corrosion prediction software was used in this Phase IV study in an effort to establish a reasonable prediction of chloride penetration rates in Hawaiian concrete when exposed to a marine environment using various corrosion inhibiting admixtures. The Phase III field test specimens were used as the source that represents the actual affects of the various admixtures when introduced into Hawaiian concrete and the prediction software was run against the field test specimens to determine the accuracy of the software parameters. The 2004 Phase III study field test specimens used the Life-365 Version 1.1 corrosion prediction software to analyze the corrosion process of the field test panels. The Phase III corrosion prediction outputs for both the 2004 and 2006 sample dates as well as the Phase IV 2008 samples are reported and will be included in this study.

2.7.1 Background to Life-365 Service Life Prediction Software

Life-365 is a service life prediction software used to predict the service life and life-cycle costs of reinforced concrete that is exposed to chlorides. The analyses performed by the Life-365 model can be broken up into four main sections. The first is a prediction of the initiation period, which is the period that the reinforcing steel is said to experience the onset of corrosion. Fick’s second law of diffusion is used as the basis for determining this time period and is further described in the following section of this chapter. The second section of the Life-365 model is the prediction of the propagation period, where the reinforcing steel reaches an unacceptable level of corrosion. The program defaults to 6 years for this unacceptable level, with the exception of epoxy-coated steel, which increases this value to 20 years. The user is able to modify this parameter based on knowledge of the local area where the structure in question exists. The third section of the Life-365 model determines a repair time frame and schedule based on the concrete properties, corrosion protection strategies, and environment of the structure being analyzed. The forth section in the Life-365 software model includes the output of estimates of the life-cycle costs of the structure being analyzed based on some parameters such as the base year of construction, projected inflation rates, and the initial project construction costs followed by the repair costs. This research report is limited to focusing on the first section of the Life-365 software model, which is the initiation period

 

14 

of chloride penetration into concrete structures. The remaining sections output by the software model will not be considered in this report.

The Life-365 program and manual consists of information and documentation from companies in the Consortium I contract including W. R. Grace Construction Products, Master Builders, and the Silica Fume Association. Under Consortium I, Version 1.0 was released in October 2000, and later revised as Version 1.1 in December 2001 to incorporate minor changes. An upcoming publication by Robertson (2012) will include the Phase III field panel chloride concentration results with Life-365 Version 1.1 and will be used to compare results to this Phase IV report. The later versions, Version 2.0 released in January 2008 and Version 2.01 released in September 2009, were developed in the Consortium II contract to include the Concrete Corrosion Inhibitors Association, the National Ready Mix Concrete Association, the Slag Cement Association, and the Silica Fume Association. Robertson (2012) noted that Version 2.0 does not allow the user as much flexibility with parameter changes as the earlier Version 1.1. The current Version 2.1 released in January 2012 includes updates with an exhaustive 12-month process of verification and validation of the software (Life-365, 2012). Although Version 2.1 was the latest available software version at the time of this report, a review of the user input options needed for comparisons with the field test specimen chloride concentration values such as indicating the month of first exposure and specifying the chloride concentrations at various ages were not included. Therefore the chloride concentration prediction values found in this report were based on the previous Version 1.1 as this was the latest software version that allowed the proper user inputs (note also that neither Version 2.0 nor Version 2.0.1 included these options). Discussions were held with the Life-365 software developer about these missing options in the later versions and consideration will be made to possibly add them back in with the next software release.

It is the intent of the Life-365 developers to hand over the software to the ACI Committee 365 for review and possible adoption as a “standard” model for service life predictions. Further background information of the development of the Life-365 software can be found in the Life-365 user’s manual (Life-365, 2012).

2.7.2 Mathematical Equations of Life-365 Service Life Prediction Model

The general mathematical premise of Life-365 is consistent between the various software versions, therefore the references made to the latest software version’s (Version 2.1) user’s manual will suffice for Version 1.1 which was used for this report. According to the Life-365 user’s manual (Life-365, 2012), the initiation period is defined as the time it takes for sufficient chlorides to penetrate the concrete cover and accumulate in sufficient quantity at the depth of the embedded steel to initiate corrosion of the steel. More specifically, this is the time period over which the concentration of chlorides reaches the critical threshold at the depth of concrete cover. The Life-365 user’s manual (Life-365, 2012) reports that the model predicts the corrosion initiation period assuming diffusion to be the dominant mechanism. Fick’s second law is the governing differential equation, given by:

(Eqn. 2.4)

where C = chloride content,

 

15 

D = apparent diffusion coefficient,

x = depth from the exposed surface, and

t = time.

The chloride diffusion coefficient is a function of both time and temperature, and Life-365 uses the following relationship to account for time-dependent changes in diffusion:

(Eqn. 2.5)

where D(t) = diffusion coefficient at time t,

Dref = diffusion coefficient at time tref (taken as 28 days in Life-365), and

m = diffusion decay index, a constant (depending on mixture proportions).

The values for Dref and m are selected by Life-365 based on the user inputs regarding mixture design details (i.e., water-cementitious material ratio, w/cm, and the type and proportion of cementitious materials). The relationship shown in Eqn. 2.5 is limited to 25 years (D25y) in order to prevent the diffusion coefficient from decreasing with time indefinitely. The diffusion coefficient for time beyond 25 years calculated in Life-365 from Eqn. 2.5 is held as a constant (for t ≥ 25, Dt = D25y).

In order to account for temperature-dependent changes in diffusion, Life-365 uses the following relationship:

, . (Eqn. 2.6)

where D(t,T) = diffusion coefficient at time t and temperature T,

Dref = diffusion coefficient at time tref and temperature Tref,

U = activation energy of the diffusion process (35,000 J/mol),

R = gas constant (8.314 J/mol.K), and

T = absolute temperature (K).

In the Life-365 model, the default values for tref and Tref are 28 days and 293K (20°C), respectively. The temperature value, T, of the concrete varies with time, t, according to the geographic location of the structure. These values can be selected from a list of pre-programmed locations in Life-365 or modified directly by the user to suit the specific location being evaluated.

The chloride exposure conditions (e.g., the rate of chloride build up at the surface and maximum chloride content) used for analysis is determined based on the type of structure (e.g., bridge deck, parking structure), the type of exposure (e.g., to marine or deicing salts) and the geographic locations selected by the user.

Finally, the initiation time of corrosion is conducted by using a finite difference implementation of Fick’s second law of diffusion (Eqn. 2.4), where the diffusion coefficient value, D, is modified at every time step using Eqn. 2.5 and Eqn. 2.6 previously described above.

 

16 

2.7.3 Assumptions and Limitations of Life-365 Service Life Prediction Software

According to the Life-365 user’s manual (Life-365, 2012), the solutions found in the Life-365 program model are only intended to be approximations and to be used as simply a guideline in designing reinforced concrete structures that are exposed to chlorides. The Life-365 documentation informs the users that the program is limited due to the fact that the chloride transport process, loss of passivity on embedded steel, corrosion of the steel and subsequent damage of the concrete surrounding the corroded steel are highly complex phenomena and not understood in their entirety. Therefore, simplifications and assumptions where included in the software model to satisfy parameters that do not include sufficient knowledge. These simplifications were made in order to give engineers, who may not have the expertise specifically in the area of chloride transport and reinforcement corrosion, a means to understand and evaluate the basic corrosion process within reinforced concrete.

This report will focus on the initiation period of the corrosion process. Calculations of the initiation period within the Life-365 software model have the following assumptions and limitations:

No damage (due to chlorides or corrosion) is assumed to occur during the initiation period. 

As stated earlier in the mathematical descriptions section, the Life‐365 program model assumes that the sole mechanism of chloride transport through the concrete is by ionic diffusion. 

Fick’s second law of diffusion is used for calculations along with an apparent chloride diffusion coefficient that characterizes the particular concrete specimen being considered. 

The concrete being modeled is assumed to be fully saturated during the analysis period. 

Concrete hydration is assumed to be complete after 25 years.  This limits the diffusion coefficient, Dt, and subsequently the time‐varying effects of the diffusion decay index, m, to remain constant beyond 25 years for analysis (see Eqn. 2.5 above). 

Unidirectional diffusion is assumed to be the only mechanism of chloride transport. 

A single chloride threshold value is assumed to be 0.05% by mass of concrete (i.e. Ct = 0.05), with the exception of the modifications for the chemical corrosion‐inhibitors further described in this section.  

The Life-365 documents note that the assumptions that the concrete remains fully saturated and that ionic diffusion is the only means for chloride ingress is an oversimplification. Other models have implemented the unsaturated effects as well as a convective chloride transport method; however, these methods were not included in the Life-365 program model in order that users may have a more simplified design tool to include a wide range of general applications.

Life-365 pays particular attention to the surface chloride concentrations on the concrete structures being analyzed. According to the user’s manual (Life-365, 2012), the surface

 

17 

chloride concentration is the main driving force for chloride penetration in Life-365. Chloride buildup rates are selected by the model based on the type of exposure that the structure is subject to as well as the geographical location of the structure. The software includes multiple exposure conditions, including marine splash zone (which is used for this particular research report). The Life-365 user’s manual (Life-365, 2012) informs the user that the database for the default surface concentrations are estimated and further calibration needs to occur. The manual goes on to instruct users to use chloride data from local sources where available and are allowed to modify these parameters within the program to reflect such local data. Table 2-2 includes the default values for build-up rates and maximum surface concentrations within marine environments that are assumed by the Life-365 software model.

Table 2-2: Default Build-up Rates and Maximum Surface Concentration for Marine Environments in Life-365 (Life-365, 2012)

Zone Build-up Rate (%/year) Maximum (%)

Marine splash zone instantaneous 0.8

Marine spray zone 0.10 1.0

Within 800 m of the ocean 0.04 0.6

Within 1.5 km of the ocean 0.02 0.6

The diffusion coefficient, Dt, the diffusion decay index, m, and the chloride threshold, Ct, vary within the software model based on the concrete mixture proportions and effects of corrosion-inhibiting admixtures and pozzolans. The base case concrete mixture in Life-365 includes plain Portland cement concrete with no admixtures or corrosion protection strategy and also assumes the following values:

D28 = 1x10(112.06+2.40w/cm) meters-squared per second (m2/s) (Eqn. 2.7)

with m = 0.20, and

Ct = 0.05 percent (% weight of concrete).

The Life-365 assumptions for the relationship between the diffusion coefficient at 28 days (D28) and the water-cementitious materials ratio (w/cm) is based on research results in bulk diffusion tests by the University of Toronto (Life-365, 2012). Figure 2-2 shows the relationship between the D28 and w/cm variables.

 

18 

Figure 2-2: Relationship Between D28 and w/cm (Life-365, 2012)

Due to the known reduction in permeability and diffusivity of concrete with the addition of silica fume in concrete, the effects of silica fume in the Life-365 program are accounted for by reducing the base case diffusion coefficient for Portland cement, Dpc, based on the amount of silica fume added (%SF) to the concrete. The following equation is used in Life-365 to represent the diffusivity changes with the addition of silica fume to the concrete mixture:

. . . (Eqn. 2.8)

Equation 2.8 is only valid in Life-365 for 15-percent or less silica fume added to the concrete mixture and will not compute higher values of silica fume added. The values of Ct and m remain unaffected as Life-365 assumes that the addition of silica fume has no

effect to these variables. Figure 2-3 shows the relationship between the diffusion coefficients and the addition of silica fume to the concrete mixture.

Relationship Between D 28 and W/CM

1E-12

1E-11

1E-10

0.3 0.4 0.5 0.6

W/CM

Diff

usio

n C

oeffi

cien

t, D

28 (

m2/s

)

 

19 

Figure 2-3: Effect of Silica Fume on DSF (Life-365, 2012)

The addition of fly ash and slag are assumed by Life-365 to have no effect on the early-age diffusion coefficient, D28, or the chloride threshold, Ct. Life-365 does however attribute changes to the diffusion decay index, m, with the addition of fly ash and/or slag. According to the Life-365 user’s manual (Life-365, 2012), many various sources have published and reported average diffusion decay index values for various concrete mixtures including fly ash and slag based mainly from marine studies. Relatively high levels of fly ash (e.g. 30 to 50 percent) and slag (e.g. 50 to 70 percent) were used to calculate the average published diffusion decay index values. These average values are shown in Table 2-3. The idea behind the rate of decay for marine conditions is that the constant supply of moisture from the ocean on most marine structures may be higher than for areas further away such as bridges and parking structures (not specifically exposed to ocean marine environments, but rather deicing salts). In a marine environment, the rate of hydration of concrete is said to be reduced compared to structures further away (bridges and parking structures) as those structures not specifically exposed to marine conditions allow for continued hydration reactions due to reduced moisture availability.

Table 2-3: Average Published Values for m, Various Concrete Mixtures (Life-365, 2012)

Concrete Mixture m PC Concrete 0.264

Fly Ash Concrete 0.700 Slag Concrete 0.620

Life-365 takes a more conservative assumption on the rate of decay of diffusion in marine environments. The program limits the range of m to vary from 0.20 to 0.60 based on the amount of fly ash (%FA) and/or slag (%SG) included in the concrete mixture. The following equation is used in Life-365 to vary m based on the fly ash and slag included in a mixture:

m = 0.2 + 0.4(%FA/50 + %SG/70) (Eqn. 2.9)

Effect of Silica Fume

0

0.2

0.4

0.6

0.8

1

0 5 10 15

Silica Fume (%)

DS

F /

DP

C (

m2/s

)

 

20 

Equation 2.9 is limited in the Life-365 program to maximum replacement values of 50 percent fly ash or 70 percent slag and will not compute diffusion values for mixtures in

excess of these percentages. Figure 2-4 and Table 2-4 indicate the effects of fly ash and slag on the diffusion coefficients in Life-365.

Currently, Life-365 Version 2.1 includes only two chemical corrosion inhibitors: calcium nitrite inhibitor (CNI) and Rheocrete 222+ (referred to as “A&E” for “amines and esters” in the program). Similarly, previous software versions including Version 1.1 are also limited to CNI and Rheocrete 222+ (with the user option to view as generic trade names or commercial trade names). The program limits the user to ten different dosage levels of 30 percent solution calcium nitrite. Life-365 also assumes that the inclusion of CNI will only effect the chloride threshold, Ct, with no effect on the diffusion coefficient, D28, or the diffusion decay index, m.

Table 2-5 lists the varying effects of CNI on the chloride threshold.

Figure 2-4: Effects of Fly Ash and Slag on Dt (Life-365, 2012)

Table 2-4: Effects of Slag and Fly Ash on Diffusion Coefficients in Life-365 (Life-365, 2012)

m D28 D10y D25y

(≤ 0.60) (x 10-13 m2/s) (x 10-13 m2/s) (x 10-13 m2/s)

Portland Cement 0.20 79 30 25

30 % Slag 0.37 79 13 9.3

40 % Fly Ash 0.52 79 6.3 3.9

Effect of Fly Ash and Slag

1E-13

1E-12

1E-11

1E-10

0.01 0.1 1 10 100

Age (years)

Diff

usio

n C

oeffi

cien

t, D

t (m

2/s

)

28 days

PC

30% SG

40% FA

 

21 

Table 2-5: Effects of CNI on Threshold Values in Life-365 (Life-365, 2012)

CNI Dose Threshold, Ct litres/m3 gal/cy (% wt. conc.)

0 0 0.05 10 2 0.15 15 3 0.24 20 4 0.32 25 5 0.37 30 6 0.40

Life-365 limits the dosage of Rheocrete 222+ to a single dose of 1 gal/yd3 (5 litres/m3) of concrete. In order to capture the effects of the Rheocrete 222+ admixture, Life-365 assumes the corrosion threshold is modified to Ct = 0.12 percent (by mass of concrete), the initial diffusion coefficient is assumed to be reduced by 90 percent from the base predicted value, and that the surface chloride build-up rate, Cs, is decreased by half (i.e. it takes twice as long to reach the chloride build-up rate when compared to the base case value).

Other corrosion inhibiting methods such as membranes, sealers, stainless steel and epoxy coated rebar are addressed in the Life-365 program. However, these methods were not included in this research project and will not be discussed. Further information about the methods, assumptions and limitations of the Life-365 program can be found in the Version 2.1 user’s manual of Life-365.

2.8 Summary

This chapter presented a literature review of information on the mechanisms of corrosion, the influences of chlorides on corrosion, chloride penetrations in concrete, and the objectives for corrosion protection of reinforcing in concrete from the different concrete admixtures. The admixtures included calcium nitrite-based corrosion inhibitors (DCI and Rheocrete CNI), Rheocrete 222+, FerroGard 901, Xypex Admix C-2000, latex modifiers, fly ash, silica fume, and Kryton KIM. A background of assumptions, limitations and mathematical methodologies of the computer software Life-365 were also presented.

 

22 

 

23 

3 EXPERIMENTAL PROCEDURES

3.1 Introduction

This chapter references and describes the materials used for all of the concrete mixtures as well as the concrete mixture proportions used to previously create the laboratory specimens of Phase II and the field specimens of Phase III. A description of the experimental procedures for measuring the concrete properties concerning chloride concentration is included. Other experimental procedures for measuring properties including slump, compressive strength, air content, elastic modulus, Poisson’s ratio and pH were described in the previous phases of this study are not described in this chapter, however some of these properties are reported in the tables within this chapter for reference.

3.2 Mixtures Created by Previous Phases of Research

Similar mixtures were previously designed for both Phase II and Phase III. A set of control mixtures was created in Phase II (Okunaga et al. 2005) and used as a base for Phase III mixtures created by Uno et al. (2004) for comparison. In addition to the control mixtures, different admixtures intended to inhibit corrosion, previously described in Chapter 2, were added into the various mixtures. For each admixture added in the Phase II and Phase III mixtures, specific parameters such as water-cement ratios, paste contents, admixture dosages or pozzolan contents and aggregate sources were varied.

The aggregate sources for the mixtures were from the Kapaa Quarry operated by Ameron and the Halawa Quarry operated by Hawaiian Cement. These aggregate sources hereinafter will be referred to as “Kapaa” and “Halawa” in the mixtures reported in the following sections. The cement that was used for all mixtures was Type I-II cement produced by Hawaiian Cement on the island of Oahu. Further details on the aggregates used in this research were reported in Phase II of this study by Pham and Newtson (2001).

Three additional admixtures, Daracem 19, Darex II AEA, and Daratard HC, were added to many of the various concrete mixture specimens to provide workability, air-entrainment and set time retarding, respectively. However, it should be noted that not all mixtures included these other admixtures as potential chemical reactions could result from combinations of the tested admixtures and have adverse effects on the properties of the concrete. The usage of these other admixtures is reflected in the tables in the following sections.

3.2.1 Control Mixtures

From the previous Phase II study, six control mixture designs were constructed from each of the aggregate sources. The mixture proportions were modified from a design mixture created by Ameron (operators of the Kapaa aggregate source) that was implemented as a means of improvement on Pier 39 in Honolulu. According to Pham and Newtson (2001) of the Phase II study, this Ameron mixture was selected for the Pier 39 improvements as it was considered an effective mixture for protecting the reinforcing steel. The control mixtures that utilized the Halawa aggregates were modeled after the Kappa aggregate

 

24 

control mixtures with adjustments made for differences between the aggregate types. The six Kapaa control mixtures are labeled C1 to C6 and the six Halawa control mixtures are labeled HC1 to HC6. A summary of the Kapaa and Halawa control mixtures from Okunaga et al. (2005) are presented in Table 3-1 and Table 3-2, respectively.

There were two control mixtures using the Kapaa aggregate source and one control mixture using the Halawa aggregate source for the construction of the Phase III panels. Panels labeled Panel 1 and Panel 7 were based on the Phase II Kapaa control mixtures C2 and C1, respectively. Panel 2 was based on the Halawa mixture HC2 from the Phase II study. The Phase III control mixtures are shown in Table 3-3.

Table 3-1: Phase II Kapaa Control Mixtures

Mixture Label C1 C2 C3 C4 C5 C6 w/c 0.35 0.40 0.45 0.35 0.40 0.45

Paste Volume (%) 31.2 31.2 31.2 32.5 32.5 32.5 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)

Maui Dune Sand (lb/yd3) 431.0 431.0 431.0 411.5 411.5 411.5

(kg/m3) (255.7) (255.7) (255.7) (244.1) (244.1) (244.1)

Kapaa Basalt Sand (lb/yd3)

825.6 825.6 825.6 788.2 788.2 788.2

(kg/m3) (489.8) (489.8) (489.8) (467.6) (467.6) (467.6)

Cement (lb/yd3) 786.1 733.2 683.7 819.6 762.5 712.8

(kg/m3) (466.4) (435.0) (405.6) (486.3) (452.4) (422.9)

Water (lb/yd3) 275.1 292.1 307.7 286.9 305.0 320.8

(kg/m3) (163.2) (173.3) (182.6) (170.2) (181.0) (190.3)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

25 

Table 3-2: Phase II Halawa Control Mixtures

Mixture Label HC1 HC2 HC3 HC4 HC5 HC6 w/c 0.35 0.40 0.45 0.35 0.40 0.45

Paste Volume (%) 28.3 28.3 28.3 29.7 29.7 29.7 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,642 1,642 1,642 1,642 1,642 1,642

(kg/m3) (974.1) (974.1) (974.1) (974.1) (974.1) (974.1)

Maui Dune Sand (lb/yd3) 572.7 572.7 572.7 547.0 547.0 547.0

(kg/m3) (339.8) (339.8) (339.8) (324.5) (324.5) (324.5)

Halawa Basalt Sand (lb/yd3)

759.2 759.2 759.2 725.2 725.2 725.2

(kg/m3) (450.4) (450.4) (450.4) (430.2) (430.2) (430.2)

Cement (lb/yd3) 786.1 733.2 683.7 819.6 762.5 712.8

(kg/m3) (466.4) (435.0) (405.6) (486.3) (452.4) (422.9)

Water (lb/yd3) 275.1 292.1 307.7 286.9 305.0 320.8

(kg/m3) (163.2) (173.3) (182.6) (170.2) (181.0) (190.3)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

26 

Table 3-3: Phase III Control Mixtures

Mixture Label Panel 1 Panel 2 Panel 7 (Based on Phase II Label) (C2) (HC2) (C1)

Aggregate Source Kapaa Halawa Kapaa w/c 0.40 0.40 0.35

Cement to Concrete Ratio (%) 18.96 18.32 20.08 Paste Volume (%) 31.2 31.2 31.2 Design Slump (in) 4 4 4

(mm) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,642 1,576

(kg/m3) (935.0) (974.1) (935.0)

Dune Sand (lb/yd3) 431.0 573.0 431.0

(kg/m3) (255.7) (340.0) (255.7)

Concrete Sand (lb/yd3) 826.5 759.2 825.7

(kg/m3) (490.4) (450.4) (489.9)

Cement (lb/yd3) 733.3 733.3 786.2

(kg/m3) (435.1) (435.1) (466.5)

Water (lb/yd3) 292.1 292.1 275.1

(kg/m3) (173.3) (173.3) (163.2)

Daratard (oz./sk) 3 3 3 (ml/sk) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 (ml/sk) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4

3.2.2 DCI Mixtures

Six DCI mixtures using the Kapaa aggregates were previously constructed in the Phase II study and denoted as D1 to D6. These mixtures were based on the Phase II control mixtures C2 (used to create mixtures D1, D2, and D3) and C4 (used to create mixtures D4, D5, and D6), however, water was replaced with the DCI admixture in increments of 2, 4, and 6 gallons per cubic yard of concrete. No mixtures using the Halawa aggregates were created in the Phase II study for the DCI admixture. The Phase II DCI mixtures are indicated in Table 3-4.

For the Phase III study, panels denoted as Panel 3 and 3A were fabricated from the Phase II Kapaa aggregate mixtures D4 and D5 respectively. Panel 3 replaced 2 gallons of water with the DCI admixture, and Panel 3A replaced 4 gallons of water with the DCI admixture. Panel 4 of the Phase III study was constructed from a similar Halawa

 

27 

aggregate mixture found in the Phase II study. The Phase III DCI mixtures are presented in Table 3-5.

Table 3-4: Phase II DCI Mixtures

Mixture Label D1 D2 D3 D4 D5 D6 w/c 0.35 0.35 0.35 0.40 0.40 0.40

Paste Volume (%) 32.5 32.5 32.5 31.2 31.2 31.2 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)

Maui Dune Sand (lb/yd3) 411.5 411.5 411.5 431.4 431.4 431.4

(kg/m3) (244.1) (244.1) (244.1) (256.0) (256.0) (256.0)

Kapaa Basalt Sand (lb/yd3)

788.2 788.2 788.2 825.6 825.6 825.6

(kg/m3) (467.6) (467.6) (467.6) (489.8) (489.8) (489.8)

Cement (lb/yd3) 819.6 819.6 819.6 733.2 733.2 733.2

(kg/m3) (486.3) (486.3) (486.3) (435.0) (435.0) (435.0)

Water (lb/yd3) 270.2 253.5 236.8 275.4 258.7 242.0

(kg/m3) (160.3) (150.4) (140.5) (163.4) (153.5) (143.6)

Liquid DCI (gal/yd3) 2 4 6 2 4 6

(l/m3) (9.9) (19.8) (29.7) (9.9) (19.8) (29.7)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

28 

Table 3-5: Phase III DCI Mixtures

Mixture Label Panel 3 Panel 3A Panel 4 (Based on Phase II Label) (D4) (D5) (none)

Aggregate Source Kapaa Kapaa Halawa w/c 0.40 0.40 0.40

Cement to Concrete Ratio (%) 18.98 18.98 18.30 Paste Volume (%) 31.2 31.2 31.2 Design Slump (in) 4 4 4

(mm) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,642 1,576

(kg/m3) (935.0) (974.1) (935.0)

Dune Sand (lb/yd3) 431.5 431.5 431.5

(kg/m3) (256.0) (256.0) (256.0)

Concrete Sand (lb/yd3) 826.5 826.5 826.5

(kg/m3) (490.4) (490.4) (490.4)

Cement (lb/yd3) 733.3 733.3 733.3

(kg/m3) (435.1) (435.1) (435.1)

Water (lb/yd3) 275.4 258.7 275.4

(kg/m3) (163.4) (153.5) (163.4)

Liquid DCI (gal/yd3) 2 4 2

(l/m3) (9.9) (19.8) (9.9)

Daratard (oz./sk) 3 3 3 (ml/sk) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 (ml/sk) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4

3.2.3 Rheocrete CNI Mixtures

The Rheocrete CNI mixtures were made by replacing the same amounts of DCI from the previous mixture designs with Rheocrete CNI as both admixtures are similar calcium nitrite-based corrosion inhibitors each containing 30% calcium nitrite.

Six Rheocrete CNI mixtures were designed from both the Kapaa and Halawa aggregate sources in the Phase II study. The Kapaa CNI mixtures are labeled CNI1 to CNI6 and the Halawa CNI mixtures are labeled HCNI1 to HCNI6. The Phase II Kapaa and Halawa mixture proportions for the Rheocrete CNI admixture are reported in Table 3-6 and Table 3-7, respectively.

 

29 

The Phase III study only used the Kapaa aggregate source for the construction of panels 5, 5A, and 6. The Kapaa CNI mixture CNI4 was used to create panels 5 and 6, and mixture CNI5 was used to create panel 5A. Panels 5 and 6 replaced 2 gallons of water with the Rheocrete CNI admixture and panel 5A replaced 4 gallons of water with the Rheocrete CNI admixture (Uno et al. 2004). No Halawa aggregate mixtures were used for the Phase III Rheocrete CNI mixtures. The Phase III Rheocrete CNI mixtures are presented in Table 3-8.

Table 3-6: Phase II Kapaa Rheocrete CNI Mixtures

Mixture Label CNI1 CNI2 CNI3 CNI4 CNI5 CNI6 w/c 0.35 0.35 0.35 0.40 0.40 0.40

Paste Volume (%) 32.5 32.5 32.5 31.2 31.2 31.2 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)

Maui Dune Sand (lb/yd3) 411.5 411.5 411.5 431.4 431.4 431.4

(kg/m3) (244.1) (244.1) (244.1) (256.0) (256.0) (256.0)

Kapaa Basalt Sand (lb/yd3)

788.2 788.2 788.2 825.6 825.6 825.6

(kg/m3) (467.6) (467.6) (467.6) (489.8) (489.8) (489.8)

Cement (lb/yd3) 819.6 819.6 819.6 733.2 733.2 733.2

(kg/m3) (486.3) (486.3) (486.3) (435.0) (435.0) (435.0)

Water (lb/yd3) 270.2 253.5 236.8 275.4 258.7 242.0

(kg/m3) (160.3) (150.4) (140.5) (163.4) (153.5) (143.6)

Liquid CNI (gal/yd3) 2 4 6 2 4 6

(l/m3) (9.9) (19.8) (29.7) (9.9) (19.8) (29.7)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

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Table 3-7: Phase II Halawa Rheocrete CNI Mixtures

Mixture Label HCNI1 HCNI2 HCNI3 HCNI4 HCNI5 HCNI6w/c 0.35 0.35 0.35 0.40 0.40 0.40

Paste Volume (%) 28.3 28.3 28.3 29.7 29.7 29.7 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,642 1,642 1,642 1,642 1,642 1,642

(kg/m3) (974.1) (974.1) (974.1) (974.1) (974.1) (974.1)

Maui Dune Sand (lb/yd3) 572.7 572.7 572.7 547.0 547.0 547.0

(kg/m3) (339.8) (339.8) (339.8) (324.5) (324.5) (324.5)

Halawa Basalt Sand (lb/yd3)

759.2 759.2 759.2 725.2 725.2 725.2

(kg/m3) (450.4) (450.4) (450.4) (430.2) (430.2) (430.2)

Cement (lb/yd3) 819.6 819.6 819.6 733.2 733.2 733.2

(kg/m3) (486.3) (486.3) (486.3) (435.0) (435.0) (435.0)

Water (lb/yd3) 270.2 253.5 236.8 275.4 258.7 242.0

(kg/m3) (160.3) (150.4) (140.5) (163.4) (153.5) (143.6)

Liquid CNI (gal/yd3) 2 4 6 2 4 6

(l/m3) (9.9) (19.8) (29.7) (9.9) (19.8) (29.7)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

31 

Table 3-8: Phase III Rheocrete CNI Mixtures

Mixture Label Panel 5 Panel 5A Panel 6 (Based on Phase II Label) (CNI4) (CNI5) (CNI4)

Aggregate Source Kapaa Kapaa Kapaa w/c 0.40 0.40 0.40

Cement to Concrete Ratio (%) 18.98 18.97 18.97 Paste Volume (%) 31.2 31.2 31.2 Design Slump (in) 4 4 4

(mm) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,576 1,642

(kg/m3) (935.0) (935.0) (974.1)

Dune Sand (lb/yd3) 431.5 431.5 572.7

(kg/m3) (256.0) (256.0) (339.8)

Concrete Sand (lb/yd3) 826.5 826.5 759.2

(kg/m3) (490.4) (490.4) (450.4)

Cement (lb/yd3) 733.3 733.3 733.3

(kg/m3) (435.1) (435.1) (435.1)

Water (lb/yd3) 275.4 258.7 275.4

(kg/m3) (163.4) (153.5) (163.4)

Liquid CNI (gal/yd3) 2 4 2

(l/m3) (9.9) (19.8) (9.9)

Daratard (oz./sk) 3 3 3 (ml/sk) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 (ml/sk) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4

3.2.4 Rheocrete 222+ Mixtures

Rheocrete 222+ mixtures were designed by adding 1 gallon of Rheocrete 222+ admixture per cubic yard of concrete to both the Kapaa and Halawa control mixtures.

The Phase II study Rheocrete 222+ mixtures that included the Kapaa aggregates are labeled RHE1 to RHE6 and are shown in Table 3-9. The Halawa Rheocrete 222+ mixtures are labeled HRHE1 to HRHE6 from the Phase II study and are indicated in Table 3-10.

The panels from the Phase III study used both the Kapaa and Halawa Phase II Rheocrete 222+ mixtures for a base design. Panels 15 and 16 were based on Kapaa mixture and

 

32 

panels 17 and 17A were constructed from a Halawa mixture. The Phase III Rheocrete 222+ mixture designs are shown in Table 3-11.

Table 3-9: Phase II Kapaa Rheocrete 222+ Mixtures

Mixture Label RHE1 RHE2 RHE3 RHE4 RHE5 RHE6 w/c 0.35 0.40 0.45 0.35 0.40 0.45

Paste Volume (%) 31.2 31.2 31.2 32.5 32.5 32.5 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)

Maui Dune Sand (lb/yd3) 431.0 431.0 431.0 411.5 411.5 411.5

(kg/m3) (255.7) (255.7) (255.7) (244.1) (244.1) (244.1)

Kapaa Basalt Sand (lb/yd3)

825.6 825.6 825.6 788.2 788.2 788.2

(kg/m3) (489.8) (489.8) (489.8) (467.6) (467.6) (467.6)

Cement (lb/yd3) 786.1 733.2 683.7 819.6 762.5 712.8

(kg/m3) (466.4) (435.0) (405.6) (486.3) (452.4) (422.9)

Water (lb/yd3) 275.1 292.1 307.7 286.9 305.0 320.8

(kg/m3) (163.2) (173.3) (182.6) (170.2) (181.0) (190.3)

Rheocrete 222+ (gal/yd3) 1 1 1 1 1 1

(l/m3) (4.95) (4.95) (4.95) (4.95) (4.95) (4.95)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

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Table 3-10: Phase II Halawa Rheocrete 222+ Mixtures

Mixture Label HRHE

1 HRHE

2 HRHE

3 HRHE

4 HRHE

5 HRHE

6 w/c 0.35 0.40 0.45 0.35 0.40 0.45

Paste Volume (%) 28.3 28.3 28.3 29.7 29.7 29.7 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,642 1,642 1,642 1,642 1,642 1,642

(kg/m3) (974.1) (974.1) (974.1) (974.1) (974.1) (974.1)

Maui Dune Sand (lb/yd3) 572.7 572.7 572.7 547.0 547.0 547.0

(kg/m3) (339.8) (339.8) (339.8) (324.5) (324.5) (324.5)

Halawa Basalt Sand (lb/yd3)

759.2 759.2 759.2 725.2 725.2 725.2

(kg/m3) (450.4) (450.4) (450.4) (430.2) (430.2) (430.2)

Cement (lb/yd3) 786.1 733.2 683.7 819.6 762.5 712.8

(kg/m3) (466.4) (435.0) (405.6) (486.3) (452.4) (422.9)

Water (lb/yd3) 275.1 292.1 307.7 286.9 305.0 320.8

(kg/m3) (163.2) (173.3) (182.6) (170.2) (181.0) (190.3)

Rheocrete 222+ (gal/yd3) 1 1 1 1 1 1

(l/m3) (4.95) (4.95) (4.95) (4.95) (4.95) (4.95)

Daratard (oz./sk) 3 3 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4 4 4

 

34 

Table 3-11: Phase III Rheocrete 222+ Mixtures

Mixture Label Panel 15 Panel 16 Panel 17 Panel 17A(Based on Phase II Label) (RHE2) (RHE2) (HRHE2) (HRHE2)

Aggregate Source Kapaa Kapaa Halawa Halawa w/c 0.40 0.40 0.40 0.40

Cement to Concrete Ratio (%) 18.93 18.94 18.28 18.29 Paste Volume (%) 31.2 31.2 31.2 31.2 Design Slump (in) 4 4 4 4

(mm) (100) (100) (100) (100)

Coarse Aggregate (lb/yd3) 1,576 1,576 1,642 1,642

(kg/m3) (935.0) (935.0) (974.1) (974.1)

Dune Sand (lb/yd3) 431.5 431.5 572.7 572.7

(kg/m3) (256.0) (256.0) (339.8) (339.8)

Concrete Sand (lb/yd3) 826.5 826.5 759.2 759.2

(kg/m3) (490.4) (490.4) (450.4) (450.4)

Cement (lb/yd3) 733.3 733.3 733.3 733.3

(kg/m3) (435.1) (435.1) (435.1) (435.1)

Water (lb/yd3) 292.1 292.1 292.1 292.1

(kg/m3) (173.3) (173.3) (173.3) (173.3)

Rheocrete 222+ (gal/yd3) 1 1 1 1

(l/m3) (4.95) (4.95) (4.95) (4.95)

Daratard (oz./sk) 3 3 3 3 (ml/sk) (88.7) (88.7) (88.7) (88.7)

Darex (oz./sk) 2 2 2 2 (ml/sk) (59.1) (59.1) (59.1) (59.1)

Design Air Content (%) 4 4 4 4

3.2.5 FerroGard 901 Mixtures

FerroGard 901 mixtures for both Phase II and Phase III were created by replacing 3 gallons of water per cubic yard of concrete with the FerroGard 901 admixture. From the Phase II study, six FerroGard 901 mixtures labeled FER1 to FER6 were constructed based on the Kapaa control mixtures. No FerroGard 901 mixtures were designed for Phase II using the Halawa aggregates. The Phase III study used the Phase II Kapaa aggregate mixture FER2 to construct panel 20 and panels 18 and 19 were fabricated from

 

35 

a Phase II Halawa mixture. The FerroGard901 mixtures of the Phase II and Phase III studies are presented in Table 3-12 and Table 3-13, respectively.

Table 3-12: Phase II Kapaa FerroGard 901 Mixtures

Mixture Label FER1 FER2 FER3 FER4 FER5 FER6 w/c 0.35 0.40 0.45 0.35 0.40 0.45

Paste Volume (%) 31.2 31.2 31.2 32.5 32.5 32.5 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100) Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)Maui Dune Sand (lb/yd3) 431.0 431.0 431.0 411.5 411.5 411.5

(kg/m3) (255.7) (255.7) (255.7) (244.1) (244.1) (244.1)Kapaa Basalt Sand (lb/yd3) 825.6 825.6 825.6 788.2 788.2 788.2

(kg/m3) (489.8) (489.8) (489.8) (467.6) (467.6) (467.6)Cement (lb/yd3) 786.1 733.2 683.7 819.6 762.5 712.8

(kg/m3) (466.4) (435.0) (405.6) (486.3) (452.4) (422.9)Water (lb/yd3) 250.1 267.1 282.7 262.0 280.0 295.8

(kg/m3) (148.4) (158.5) (167.7) (155.4) (166.1) (175.5)FerroGard 901 (gal/yd3) 3 3 3 3 3 3

(l/m3) (14.85) (14.85) (14.85) (14.85) (14.85) (14.85)Daratard (oz./sk) 2 2 2 2 2 2

(ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1) Darex (oz./sk) 2 2 2 2 2 2

(ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1) Design Air Content (%) 4 4 4 4 4 4

 

36 

Table 3-13: Phase III FerroGard 901 Mixtures

Mixture Label Panel 18 Panel 19 Panel 20 (Based on Phase II Label) (none) (none) (FER2)

Aggregate Source Halawa Halawa Kapaa w/c 0.40 0.40 0.40

Cement to Concrete Ratio (%) 18.29 18.29 18.95 Paste Volume (%) 31.2 31.2 31.2 Design Slump (in) 4 4 4

(mm) (100) (100) (100) Coarse Aggregate (lb/yd3) 1,642 1,642 1,576

(kg/m3) (974.2) (974.2) (935.0) Dune Sand (lb/yd3) 759.2 759.2 431.0

(kg/m3) (450.4) (450.4) (255.7) Concrete Sand (lb/yd3) 572.7 572.7 826.5

(kg/m3) (339.8) (339.8) (490.4) Cement (lb/yd3) 733.3 733.3 733.3

(kg/m3) (435.1) (435.1) (435.1) Water (lb/yd3) 292.1 292.1 292.1

(kg/m3) (173.3) (173.3) (173.3) FerroGard 901 (gal/yd3) 3 3 3

(l/m3) (14.85) (14.85) (14.85) Daratard (oz./sk) 3 3 3

(ml/sk) (88.7) (88.7) (88.7) Darex (oz./sk) 2 2 2

(ml/sk) (59.1) (59.1) (59.1) Design Air Content (%) 4 4 4

3.2.6 Xypex Admix C-2000 Mixture

Xypex Admix C-2000 mixtures for both the Phase II and Phase III studies were created by replacing 2% of cement by mass with the Xypex Admix C-2000 admixture. From the Phase II study, six Xypex Admix C-2000 mixtures labeled XYP1 to XYP6 were constructed based on the Kapaa control mixtures. The Phase III study used the Phase II Kapaa aggregate mixture XYP2 to construct panel 21. No Xypex Admix C-2000 mixtures were designed for Phase II or Phase III using the Halawa aggregates. The Xypex Admix C-2000 mixtures of the Phase II and Phase III studies are presented in Table 3-14 and Table 3-15, respectively.

 

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Table 3-14: Phase II Kapaa Xypex Admix C-2000 Mixtures

Mixture Label XYP1 XYP2 XYP3 XYP4 XYP5 XYP6 w/c 0.35 0.40 0.45 0.35 0.40 0.45

Paste Volume (%) 31.2 31.2 31.2 32.5 32.5 32.5 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100) Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)Maui Dune Sand (lb/yd3) 431.0 431.0 431.0 411.5 411.5 411.5

(kg/m3) (255.7) (255.7) (255.7) (244.1) (244.1) (244.1)Kapaa Basalt Sand

(lb/yd3) 825.6 825.6 825.6 788.2 788.2 788.2

(kg/m3) (489.8) (489.8) (489.8) (467.6) (467.6) (467.6)Cement (lb/yd3) 770.4 718.5 670.0 803.2 747.3 698.6

(kg/m3) (457.1) (426.3) (397.5) (476.5) (443.3) (414.4)Water (lb/yd3) 275.1 292.1 307.7 286.9 305.0 320.8

(kg/m3) (163.2) (173.3) (182.5) (170.2) (180.9) (190.3)Xypex (lb/yd3) 15.72 14.70 13.70 16.40 15.80 14.30

(kg/m3) (9.33) (8.72) (8.13) (9.73) (9.37) (8.48) Darex (oz./sk) 2 2 2 2 2 2

(ml/sk) (59.1) (59.1) (59.1) (59.1) (59.1) (59.1) Design Air Content (%) 4 4 4 4 4 4

 

38 

Table 3-15: Phase III Xypex Admix C-2000 Mixture

Mixture Label Panel 21

(Based on Phase II Label) (XYP2) Aggregate Source Kapaa

w/c 0.40 Cement to Concrete Ratio (%) 18.75

Paste Volume (%) 31.2 Design Slump (in) 4

(mm) (100) Coarse Aggregate (lb/yd3) 1,576

(kg/m3) (935.0) Dune Sand (lb/yd3) 431.0

(kg/m3) (255.7) Concrete Sand (lb/yd3) 825.6

(kg/m3) (489.8) Cement (lb/yd3) 718.5

(kg/m3) (426.3) Water (lb/yd3) 292.1

(kg/m3) (173.3) Xypex (lb/yd3) 14.70

(kg/m3) (8.72) Daratard (oz./sk) 3

(ml/sk) (88.7) Darex (oz./sk) 2

(ml/sk) (59.1) Design Air Content (%) 4

3.2.7 Latex Modified Mixtures

Latex-modified mixtures for the Phase II study were created by adding latex in amounts of 2.5, 5.0, and 7.5 percent of the mass of cement.

From the Phase II study, six latex-modified mixtures labeled L1 to L6 were constructed based on the Kapaa control mixtures. Mixtures L1, L2, and L3 used the Kapaa control mixture C1 and mixtures L4, L5, and L6 used the Kapaa control mixture C2.

The Phase III study based the design of panel 14 from the Phase II Kapaa latex-modified mixture L5 and control mixture C2 by adding 5% latex content. No latex-modified mixtures were designed for Phase II or Phase III using the Halawa aggregates. The latex-modified mixtures of the Phase II and Phase III studies are presented in Table 3-16 and Table 3-17, respectively.

 

39 

Table 3-16: Phase II Kapaa Latex-Modified Mixtures

Mixture Label L1 L2 L3 L4 L5 L6 w/c 0.35 0.35 0.35 0.40 0.40 0.40

Paste Volume (%) 31.2 31.2 31.2 31.2 31.2 31.2 Design Slump (in) 4 4 4 4 4 4

(mm) (100) (100) (100) (100) (100) (100) Coarse Aggregate (lb/yd3) 1,576 1,576 1,576 1,576 1,576 1,576

(kg/m3) (935.0) (935.0) (935.0) (935.0) (935.0) (935.0)Maui Dune Sand (lb/yd3) 414.2 397.3 380.5 412.2 399.5 383.8

(kg/m3) (245.7) (235.7) (225.7) (244.5) (237.0) (227.7)Kapaa Basalt Sand

(lb/yd3) 793.4 761.1 728.9 795.3 765.2 735.1

(kg/m3) (470.7) (451.5) (432.4) (471.8) (454.0) (436.1)Cement (lb/yd3) 786.1 786.1 786.1 733.2 733.2 733.2

(kg/m3) (466.4) (466.4) (466.4) (435.0 (435.0 (435.0 Water (lb/yd3) 216.2 157.2 98.3 237.1 182.1 127.1

(kg/m3) (128.3) (93.3) (58.3) (140.7) (108.0) (75.4) Latex Liquid (lb/yd3) 78.6 157.2 235.8 73.3 146.6 220.0

(kg/m3) (46.6) (93.3) (140.0) (43.5) (87.0) (130.5)Design Air Content (%) 4 4 4 4 4 4

 

40 

Table 3-17: Phase III Latex-Modified Mixture

Mixture Label Panel 14 (Based on Phase II Label) (L5)

Aggregate Source Kapaa w/c 0.40

Cement to Concrete Ratio (%) 19.28 Paste Volume (%) 31.2 Design Slump (in) 4

(mm) (100) Coarse Aggregate (lb/yd3) 1,576

(kg/m3) (935.0) Dune Sand (lb/yd3) 399.5

(kg/m3) (237.0) Concrete Sand (lb/yd3) 765.2

(kg/m3) (435.0) Cement (lb/yd3) 733.2

(kg/m3) (435.0) Water (lb/yd3) 182.1

(kg/m3) (108.0) Latex Liquid (lb/yd3) 146.6

(kg/m3) (87.0) Design Air Content (%) 4

3.2.8 Fly Ash Mixtures

The fly ash material used for both Phase II and Phase III was obtained locally from a coal power plant on Oahu. It was noted that the locally supplied fly ash material does not meet the requirements for ASTM C 618 class C or class F type fly ash. Table 3-18, reproduced by Pham and Newtson (2001), presents the chemical composition of the locally supplied fly ash compared to the ASTM class C and class F fly ash requirements.

Table 3-18: Fly Ash Chemical Composition (Pham and Newtson 2001)

Chemical Composition (%) ASTM C 618 Specifications

Hawaiian Fly

Ash Class C Class F

Total Silica, Aluminum, Iron 56.09 70.0 Min 50.0 Min Sulfur Trioxide 9.85 5.0 Max 5.0 Max Calcium Oxide 25.99

Moisture Content 0.1 3.0 Max 3.0 Max Loss of Ignition 2.81 6.0 Max 6.0 Max

Available Alkalis (as Na2O) 1.26 1.5 Max 1.5 Max

 

41 

Ten Phase II Kapaa mixtures containing fly ash were created and labeled FA2 to FA11. These mixtures replace 5, 10, and 15 percent of mass of cement with fly ash. The Phase II Kapaa mixture labeled SF1 was used as a control mixture for both fly ash and silica fume as no fly ash or silica fume was added due to no Kapaa aggregates in the base control mixtures having a water-to-cement ratio of 0.36. The Phase II Kapaa fly ash mixtures are presented in Table 3-19.

Six Phase II Halawa mixtures containing fly ash were created and labeled HFA2 to HFA4 and HFA7 to HFA9 and follow the same mixture variations as the Kapaa mixtures FA2 to FA4 and FA7 to FA9. The Halawa mixture labeled HFA1 is a control mixture created with Halawa aggregates, but like the SF1 control mixture, does not contain fly ash or silica fume. The Phase II Halawa fly ash mixtures are presented in Table 3-20.

The Phase III fly ash mixtures followed the same proportions as Phase II. Panel 11 used the Phase II Kapaa design mixture FA4 and panels 12 and 13 used the Halawa fly ash mixture HFA4 from Phase II as a design base. The Phase III fly ash mixtures are presented in Table 3-21.

 

42 

Table 3-19: Phase II Kapaa Fly Ash Mixtures

FA

11

0.45

34.6

8-10

(200

-25

0)

1,66

8

(989

)

500.

4

(296

.9)

663.

3

(393

.5)

635.

4

(377

.0)

336.

4

(199

.6)

112.

13

(66.

53)

1

FA

10

0.45

34.6

8-10

(200

-25

0)

1,66

8

(989

)

500.

4

(296

.9)

663.

3

(393

.5)

676.

4

(401

.3)

338.

2

(200

.6)

75.1

5

(44.

59)

1

FA

9

0.45

35.0

8-10

(200

-25

0)

1,66

8

(989

)

493.

5

(292

.8)

654.

1

(388

.1)

642.

2

(381

.0)

340.

0

(201

.7)

113.

33

(67.

24)

1

FA

8

0.45

34.8

8-10

(200

-25

0)

1,66

8

(989

)

496.

9

(294

.8)

658.

7

(390

.8)

680

(403

.4)

340.

0

(201

.7)

75.5

6

(44.

83)

1

FA

7

0.45

34.6

8-10

(200

-25

0)

1,66

8

(989

)

500.

4

(296

.9)

663.

3

(393

.5)

717.

8

(425

.8)

340.

0

(201

.7)

37.7

8

(22.

42)

1

FA

6

0.36

32.8

8-10

(200

-25

0)

1,66

8

(989

)

533.

9

(316

.8)

707.

7

(419

.9)

681.

1

(404

.1)

288.

5

(171

.1)

120.

19

(71.

31)

1

FA

5

0.36

32.8

8-10

(200

-25

0)

1,66

8

(989

)

533.

9

(316

.8)

707.

7

(419

.9)

725.

5

(430

.4)

290.

2

(172

.2)

80.6

1

(47.

82)

1

FA

4

0.36

33.2

8-10

(200

-25

0)

1,66

8

(989

)

526.

4

(312

.3)

697.

8

(414

.0)

689.

4

(409

.0)

292.

0

(173

.2)

121.

65

(72.

17)

1

FA

3

0.36

33.0

8-10

(200

-25

0)

1,66

8

(989

)

530.

2

(314

.6)

702.

8

(416

.9)

729.

9

(433

.0)

292.

0

(173

.2)

81.1

0

(48.

12)

1

FA

2

0.36

32.8

8-10

(200

-25

0)

1,66

8

(989

)

533.

9

(316

.8)

707.

74

(419

.9)

771

(457

.4)

292.

0

(173

.2)

40.0

0

(23.

73)

1

Mix

ture

Lab

el

w/(

c+fa

)

Pas

te V

olum

e (%

)

Des

ign

Slu

mp

(in)

(mm

)

Coa

rse

Agg

rega

te

(lb/

yd3 )

(kg/

m3 )

Mau

i Dun

e S

and

(lb/

yd3 )

(kg/

m3 )

Kap

aa B

asal

t San

d (l

b/yd

3 )

(kg/

m3 )

Cem

ent (

lb/y

d3 )

(kg/

m3 )

Wat

er (

lb/y

d3 )

(kg/

m3 )

Fly

Ash

(lb

/yd3 )

(kg/

m3 )

Des

ign

Air

Con

tent

(%

)

 

43 

Table 3-20: Phase II Halawa Fly Ash Mixtures

HF

A9

0.45

32.8

8-10

(200

-250

)

1,73

7

(1,0

31)

516.

3

(306

.3)

684.

3

(406

.0)

642.

2

(381

.0)

340.

0

(201

.7)

113.

3

(67.

24)

1

HF

A8

0.45

32.6

8-10

(200

-250

)

1,73

7

(1,0

31)

519.

9

(308

.4)

689.

1

(408

.8)

680.

0

(403

.4)

340.

0

(201

.7)

75.6

(44.

83)

1

HF

A7

0.45

32.5

8-10

(200

-250

)

1,73

7

(1,0

31)

523.

5

(310

.6)

693.

3

(411

.3)

717.

8

(425

.8)

340.

0

(201

.7)

37.8

(22.

41)

1

HF

A4

0.36

30.4

8-10

(200

-250

)

1,73

7

(1,0

31)

550.

8

(326

.8)

730.

1

(433

.2)

689.

4

(409

.0)

292.

0

(173

.2)

121.

7

(72.

17)

1

HF

A3

0.36

30.1

8-10

(200

-250

)

1,73

7

(1,0

31)

554.

6

(329

.0)

735.

2

(436

.2)

729.

9

(433

.0)

292.

0

(173

.2)

81.1

(48.

11)

1

HF

A2

0.36

29.9

8-10

(200

-250

)

1,73

7

(1,0

31)

558.

6

(331

.4)

740.

4

(439

.3)

771.

0

(457

.4)

292.

0

(173

.2)

40.0

(23.

73)

1

HS

F1

0.36

29.7

8-10

(200

-250

)

1,73

7

(1,0

31)

562.

4

(333

.7)

745.

5

(442

.3)

811.

0

(481

.1)

292.

0

(173

.2)

0.0

(0.0

0)

1

Mix

ture

Lab

el

w/(

c+fa

)

Pas

te V

olum

e (%

)

Des

ign

Slu

mp

(in)

(mm

)

Coa

rse

Agg

rega

te (

lb/y

d3 )

(kg/

m3 )

Mau

i Dun

e S

and

(lb/

yd3 )

(kg/

m3 )

Hal

awa

Bas

alt S

and

(lb/

yd3 )

(kg/

m3 )

Cem

ent (

lb/y

d3 )

(kg/

m3 )

Wat

er (

lb/y

d3 )

(kg/

m3 )

Fly

Ash

(lb

/yd3 )

(kg/

m3 )

Des

ign

Air

Con

tent

(%

)

 

44 

Table 3-21: Phase III Fly Ash Mixtures

Mixture Label Panel 11 Panel 12 Panel 13 (Based on Phase II Label) (FA4) (HFA4) (HFA4)

Aggregate Source Kapaa Halawa Halawa w/(c+fa) 0.36 0.36 0.36

Cement to Concrete Ratio (%) 17.24 16.73 16.73 Paste Volume (%) 33.0 33.0 33.0 Design Slump (in) 8-10 8-10 8-10

(mm) (200-250) (200-250) (200-250)

Coarse Aggregate (lb/yd3) 1,668 1,737 1,737

(kg/m3) (989.6) (1030.6) (1030.6)

Dune Sand (lb/yd3) 526.5 548.9 548.9

(kg/m3) (312.4) (325.7) (325.7)

Concrete Sand (lb/yd3) 698.0 727.4 727.4

(kg/m3) (414.1) (431.6) (431.6)

Cement (lb/yd3) 689.3 689.3 689.3

(kg/m3) (409.0) (409.0) (409.0)

Water (lb/yd3) 291.9 291.9 291.9

(kg/m3) (173.2) (173.2) (173.2)

Fly Ash (lb/yd3) 121.77 121.77 121.77

(kg/m3) (72.2) (72.2) (72.2)

Design Air Content (%) 1 1 1

3.2.9 Silica Fume Mixtures

The silica fume mixtures for the Phase II study were designed based on the mixtures used for the Ford Island Bridge Project on Oahu as well as the Portland Cement Association recommendations and included the Force 10,000D silica fume admixture. Water cement ratios of 0.36 and 0.45 were used for these mixtures. Equivalent weights of cement were replaced with silica fume and proportioned in increments ranging from 5 to 15 percent.

Ten Phase II Kapaa silica fume mixtures were created with the Force 10,000D silica fume and labeled SF2 to SF11. Mixture SF1 served as a control mixture that did not contain any silica fume or fly ash. Mixtures SF2 to SF6 were based on the design mixtures of the Ford Island Bridge Project as these mixtures were similar to the Pier 39 improvements in that they were considered effective for protecting the reinforcing steel (Pham and Newtson 2001). Mixtures SF7 to SF11 used the Portland Cement

 

45 

Association’s mixture design recommendations. The Phase II Kapaa silica fume mixtures are presented in Table 3-22.

The Phase II study also used Halawa aggregates with two different silica fume admixtures, Force 10,000D and Rheomac SF100. Six mixtures using the Force 10,000D silica fume and are labeled HSF1 to HSF4 and HSF7 to HSF8. Six silica fume mixtures were also made with Rheomac SF100 and are labeled HSF-R2 to HSF-R4 and HSF-R7 to HSF-R9. The Phase II Halawa silica fume mixtures including Force 10,000D and Rheomac SF100 admixtures are presented in Table 3-23 and Table 3-24, respectively.

The Phase III silica fume mixtures were designed based on the Phase II Kapaa mixture SF2. Similar to the Phase II mixture SF2, panels 8 and 9 were fabricated using the Force 10,000D silica fume admixture. However, panel 10 used the Rheomac SF100 silica fume admixture. The Phase III silica fume mixtures are presented in Table 3-25.

 

46 

Table 3-22: Phase II Kapaa Silica Fume Mixtures

SF

11

0.45

34.7

8-10

(200

-25

0)

1,66

8

(989

)

497.

9

(295

.4)

660.

1

(391

.6)

631.

1

(374

.4)

334.

1

(198

.2)

111.

36

(66.

07)

1

SF

10

0.45

34.7

8-10

(200

-25

0)

1,66

8

(989

)

497.

9

(295

.4)

660.

1

(391

.6)

674.

0

(399

.9)

337.

0

(200

.0)

74.8

9

(44.

43)

1

SF

9

0.45

35.3

8-10

(200

-25

0)

1,66

8

(989

)

486.

5

(288

.6)

644.

8

(382

.6)

642.

2

(381

.0)

340.

0

(201

.7)

113.

33

(67.

24)

1

SF

8

0.45

35.0

8-10

(200

-25

0)

1,66

8

(989

)

492.

2

(292

.0)

652.

5

(387

.1)

680.

0

(403

.4)

340.

0

(201

.7)

75.5

6

(44.

83)

1

SF

7

0.45

34.7

8-10

(200

-25

0)

1,66

8

(989

)

497.

9

(295

.4)

660.

1

(391

.6)

717.

8

(425

.8)

340.

0

(201

.7)

37.7

8

(22.

42)

1

SF

6

0.36

32.9

8-10

(200

-25

0)

1,66

8

(989

)

531.

3

(315

.2)

704.

3

(417

.9)

675.

77

(400

.9)

286.

21

(169

.8)

119.

25

(70.

75)

1

SF

5

0.36

32.9

8-10

(200

-25

0)

1,66

8

(989

)

531.

3

(315

.2)

704.

3

(417

.9)

722.

62

(428

.7)

289.

05

(171

.5)

80.2

9

(47.

64)

1

SF

4

0.36

33.6

8-10

(200

-25

0)

1,66

8

(989

)

519.

2

(308

.0)

688.

2

(408

.3)

689.

35

(409

.0)

290.

2

(172

.2)

121.

65

(72.

17)

1

SF

3

0.36

33.3

8-10

(200

-25

0)

1,66

8

(989

)

525.

4

(311

.7)

696.

4

(413

.2)

729.

9

(433

.0)

292.

0

(173

.2)

81.1

0

(48.

12)

1

SF

2

0.36

32.9

8-10

(200

-25

0)

1,66

8

(989

)

531.

3

(315

.2)

704.

3

(417

.9)

771.

0

(457

.4)

292.

0

(173

.2)

40.0

0

(23.

73)

1

SF

1

0.36

32.6

8-10

(200

-25

0)

1,66

8

(989

)

537.

6

(319

.0)

712.

6

(422

.8)

811.

0

(481

.1)

292.

0

(173

.2)

0

(0.0

0)

1

Mix

ture

Lab

el

w/(

c+sf

)

Pas

te V

olum

e (%

)

Des

ign

Slu

mp

(in)

(mm

)

Coa

rse

Agg

rega

te

(lb/

yd3 )

(kg/

m3 )

Mau

i Dun

e S

and

(lb/

yd3 )

(kg/

m3 )

Kap

aa B

asal

t San

d (l

b/yd

3 )

(kg/

m3 )

Cem

ent (

lb/y

d3 )

(kg/

m3 )

Wat

er (

lb/y

d3 )

(kg/

m3 )

Sil

ica

Fum

e (l

b/yd

3 )

(kg/

m3 )

Des

ign

Air

Con

tent

(%

)

 

47 

Table 3-23: Phase II Halawa Force 10,000D Silica Fume Mixtures

Mixture Label HSF1 HSF2 HSF3 HSF4 HSF7 HSF8 w/(c+sf) 0.36 0.36 0.36 0.36 0.45 0.45

Paste Volume (%) 29.7 30.1 30.4 30.8 32.6 32.9 Design Slump (in) 8-10 8-10 8-10 8-10 8-10 8-10

(mm) (200-250)

(200-250)

(200-250)

(200-250)

(200-250)

(200-250)

Coarse Aggregate (lb/yd3) 1,737 1,737 1,737 1,737 1,737 1,737

(kg/m3) (1,031) (1,031) (1,031) (1,031) (1,031) (1,031)

Maui Dune Sand (lb/yd3) 562.4 556.0 549.5 543.1 521.1 515.1

(kg/m3) (333.7) (329.9) (326.0) (322.2) (309.2) (305.6)

Halawa Basalt Sand (lb/yd3)

745.5 737.1 728.4 719.9 690.8 682.8

(kg/m3) (442.3) (437.3) (432.1) (427.1) (409.8) (405.1)

Cement (lb/yd3) 811.0 771.0 729.9 689.4 717.8 680.0

(kg/m3) (481.1) (457.4) (433.0) (409.0) (425.8) (403.4)

Water (lb/yd3) 292.0 292.0 292.0 292.0 340.0 340.0

(kg/m3) (173.2) (173.2) (173.2) (173.2) (201.7) (201.7)

Force 10,000D (lb/yd3) 0.0 40.00 81.10 121.65 37.78 75.56

(kg/m3) (0.00) (23.73) (48.11) (72.17) (22.41) (44.83)

Design Air Content (%) 1 1 1 1 1 1

 

48 

Table 3-24: Phase II Halawa Rheomac SF100 Mixtures

Mixture Label HSF-R2 HSF-R3 HSF-R4 HSF-R7 HSF-R8 HSF-R9 w/(c+sf) 0.36 0.36 0.36 0.45 0.45 0.45

Paste Volume (%) 30.1 30.4 30.8 31.9 32.2 32.6 Design Slump (in) 8-10 8-10 8-10 8-10 8-10 8-10

(mm) (200-250)

(200-250)

(200-250)

(200-250)

(200-250)

(200-250)

Coarse Aggregate (lb/yd3) 1,737 1,737 1,737 1,737 1,737 1,737

(kg/m3) (1,031) (1,031) (1,031) (1,031) (1,031) (1,031)

Maui Dune Sand (lb/yd3) 556.0 549.5 543.1 521.1 515.1 509.1

(kg/m3) (329.9) (326.0) (322.2) (309.2) (305.6) (302.0)

Halawa Basalt Sand (lb/yd3)

737.1 728.4 719.9 690.8 682.8 674.8

(kg/m3) (437.3) (432.1) (427.1) (409.8) (405.1) (400.3)

Cement (lb/yd3) 771.0 729.9 689.4 717.8 680.0 642.2

(kg/m3) (457.4) (433.0) (409.0) (425.8) (403.4) (381.0)

Water (lb/yd3) 292.0 292.0 292.0 340.0 340.0 340.0

(kg/m3) (173.2) (173.2) (173.2) (201.7) (201.7) (201.7)

Rheomac SF100 (lb/yd3) 40.00 81.10 121.65 37.78 75.56 113.33

(kg/m3) (23.73) (48.11) (72.17) (22.41) (44.83) (67.24)

Design Air Content (%) 1 1 1 1 1 1

 

49 

Table 3-25: Phase III Silica Fume Mixtures

Mixture Label Panels 8 Panel 9 Panel 10 (Based on Phase II Label) (SF2) (SF2) (SF2)

(Silica Fume Type) Force

10,000D Force

10,000D Rheomac

SF100 Aggregate Source Kapaa Kapaa Kapaa

w/(c+sf) 0.36 0.36 0.36 Cement to Concrete Ratio (%) 19.40 19.42 19.42

Paste Volume (%) 32.9 32.9 32.9 Design Slump (in) 8-10 8-10 8-10

(mm) (200-250) (200-250) (200-250)

Coarse Aggregate (lb/yd3) 1,668 1,668 1,668

(kg/m3) (989.6) (989.6) (989.6)

Dune Sand (lb/yd3) 521.1 521.1 521.1

(kg/m3) (309.2) (309.2) (309.2)

Concrete Sand (lb/yd3) 679.3 679.3 679.3

(kg/m3) (403.0) (403.0) (403.0)

Cement (lb/yd3) 771.1 771.1 771.1

(kg/m3) (457.5) (457.5) (457.5)

Water (lb/yd3) 291.9 291.9 291.9

(kg/m3) (173.2) (173.2) (173.2)

Silica Fume (lb/yd3) 40 40 40

(kg/m3) (23.7) (23.7) (23.7)

Design Air Content (%) 4 4 4

3.2.10 Kryton KIM Mixtures

Kryton KIM admixture was not used in any of the Phase II mixtures. The Phase III study created panel 22, which included adding Kryton KIM at a proportion of 2 percent by weight of the cementitious materials up to a maximum of 13.5 pounds per cubic yard. The water content of this mixture was reduced by 5 percent to meet design slump requirements. The Phase III Kryton KIM mixture is presented in Table 3-26.

 

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Table 3-26: Phase III Kryton KIM Mixture

Mixture Label Panel 22 (Based on Phase II Label) (none)

Aggregate Source Kapaa w/c 0.40

Cement to Concrete Ratio (%) 19.00 Paste Volume (%) 31.2 Design Slump (in) 4

(mm) (100)

Coarse Aggregate (lb/yd3) 1,576

(kg/m3) (935.0)

Dune Sand (lb/yd3) 431.5

(kg/m3) (256.0)

Concrete Sand (lb/yd3) 826.5

(kg/m3) (490.3)

Cement (lb/yd3) 733.3

(kg/m3) (435.1)

Water (lb/yd3) 278.6

(kg/m3) (165.3)

Kryton KIM (lb/yd3) 13.50

(kg/m3) (6.1)

Design Air Content (%) 4

3.3 Phase III Field Specimen Fabrications

A total of twenty-five field panel specimens were fabricated in the Phase III study by Uno et al. (2004). Each panel was constructed to measure 21 inches in width, 59.5 inches in length, and 6 inches in thickness. The panels were fabricated with two layers of No. 4 reinforcing steel bars consisting of four longitudinal bars and seven transverse bars each layer. The reinforcing bar layers were separated by PVC conduit spacers to ensure physical and electrical separation between the layers. A concrete clear cover of exactly 1.5 inches was used for the test surface of the panels, with the remaining sides and tops of the panels having concrete coverage of at least 2.0 inches. Diagrams of the concrete panel dimensions and reinforcing steel layout are shown in Figure 3-1 and Figure 3-2, respectively (Uno et al. 2004).

 

51 

Figure 3-1: Typical Phase III Field Specimen Geometry (Uno et al. 2004)

 

52 

 Figure 3-2: Typical Phase III Panel Reinforcing Steel Layout (Uno et al. 2004)

3.3.1 Phase III Field Specimen Test Preparations

Similar to the Phase II study preparations, the reinforcing steel used in the fabrication of each of the Phase III field test specimens were soaked in a 10 percent sulfuric acid solution for 30 minutes to one hour and then wired brushed to ensure no initial corrosion existed prior to casting the specimens. Additional soaking ranging from 10 to 20 minutes and more scrubbing occurred depending on the condition of the reinforcing bars to be cast into the concrete panels.

 

53 

Upon casting the concrete, each reinforced concrete panel was allowed to wet cure for 7 days. After the 7 day cure time, the field panel specimens were placed at Pier 38 in the Honolulu Harbor on the island of Oahu as shown in Figure 3-3. Stainless steel cables were used to anchor each panel to the pier and the panels were lowered into the ocean such that the mean sea level was just below the mid-height of each panel. The placement of the field panels are shown in Figure 3-4 (Uno et al. 2004).

Figure 3-3: Location of Field Panels at Pier 38 Honolulu Harbor

 

54 

Figure 3-4: Placement of the Phase III Field Panels at Pier 38 (Uno et al. 2004)

3.4 Phase III & Phase IV Testing Procedures for Chemical Tests

The field panels were first placed in the ocean at Pier 38 in Honolulu Harbor between July 2002 and July 2003 by Uno et al. (2004). The concrete cores from the field test specimens were collected in 2004 and 2006 and tested under the Phase III studies of Uno et al. (2004) and Cheng and Robertson (2006). Additional samples were collected in 2008 and tested under this Phase IV study to give an average of 5 years of exposure to a marine environment. The following sections describe the testing procedures used to collect and sample the chloride concentration levels in the field test specimens after each test period.

3.4.1 Phase III Test for Chloride Concentrations for 2004 Samples

Concrete samples taken from the field panels were first collected around March 2004 by Uno et al. (2004). Chloride concentrations for these field test specimens in the Phase III study were measured using an acid-soluble chloride test. For the testing method used by the study done by Uno et al. (2004), a drill with a 0.75 inch diameter drill bit was used to drill holes at three different locations on the top face of each panel down from the surface to depths of 0.5 inch, 1.0 inch, and 1.5 inches as shown in Figure 3-5. The three locations sampled included the upper half, lower half and at the tidal zone areas along the panels. Dust samples were collected at 0.25 inches above and below each of the drilled depths to form an average result for each depth. Approximately 0.11 ounces (3 grams) of each dust

 

55 

sample was dissolved in 0.67 fluid ounces (20 mL) of extraction liquid provided by James Instruments, Inc. The dust samples were then shaken and allowed to react with the extraction liquid for one minute before taking measurements. The CL-2000 Chloride Field Test System by James Instruments, Inc. was calibrated and the instrument’s instructions for test procedures were followed to measure the chloride concentration of the collected dust samples (Uno et al. 2004). Chloride concentration readings were taken for each sample as a percentage by mass of concrete.

Figure 3-5: Phase III Chloride Sample Depths by Drill Method.

3.4.2 Phase III Test for Chloride Concentrations for 2006 Samples

Concrete samples from the field panels were collected again around January 2006 under the research of Cheng and Robertson (2006). Unlike the first method of using a drill bit to collect the set of samples, a core method was used to collect the samples at the desired depths by using a 1.5 inch diameter by 3 inch length core driller. Cores were taken from the upper half, lower half and tidal zone areas of each panel. Each core was sliced at the 0.5 inch, 1.0 inch, 1.5 inch and 2.0 inch depths to a thickness of approximately 1mm by a wet concrete saw. The slices were crushed into dust and tested in the same manner as the previous test method for the 2004 samples with the CL-2000 Chloride Field Test System by James Instruments, Inc. This method is shown in Figure 3-6.

 

56 

Figure 3-6: Phase III & Phase IV Chloride Sample Depths by Core Method.

3.4.3 Phase IV Test for Chloride Concentrations for 2008 Samples

Additional field panel samples were taken between February 2007 and March 2008 after an average of 5 years of exposure to the ocean and are reported in this Phase IV study. The same core method used to collect the samples in the 2006 test period was used for all samples collected at the 2008 test period. Again, cores were taken from the upper half, lower half and tidal zone areas of each panel. The 2008 samples included additional chloride concentrations taken from the test face surface of the cores. Unlike the 2006 slice method, each core was sliced at the surface, 0.5 inch, 1.0 inch, 1.5 inch and 2.0 inch depths to a thickness of approximately 1mm by a dry concrete saw to reduce the amount of chloride concentrations from being washed away by the water used for wet concrete saw methods. This similar method is again shown in Figure 3-6.

3.5 Half-cell Potential Tests

The half-cell potential tests used for all phases of this research were performed using a saturated calomel electrode (SCE) and a voltmeter. During the field panel fabrications previous created in Phase III by Uno et al. (2004), a test access hole was made at the top of each panel allowing a single longitudinal steel reinforcing bar to be exposed. A steel screw along with attached electrical wires was drilled into the exposed rebar for a positive electrical connection point. This test hole was sealed each time after readings were taken and prior to replacement into the ocean for continued testing. This test set up is shown in Figure 3-7.

The half-cell potential tests performed by Uno et al. (2004) provided ten different locations along the test face of each field panel. The later tests to date, starting with Cheng and Robertson (2006), included eight additional test locations for a total of eighteen to provide a more accurate average of test results. Figure 3-8 indicates the test locations taken along the face of each field panel.

 

57 

Figure 3-7: Electrical Connection to Rebar for Half-cell Tests

Figure 3-8: Half-cell Test Locations

 

58 

3.6 Life-365 Corrosion Prediction Software Set Up

This Phase IV research included the corrosion prediction software, Life-365 Version 1.1, which was used to analyze each field panel and predict the chloride concentrations through the depths of each concrete specimen. Default and user modified input parameters found within the program were used for comparison with the field panel chloride concentration samples previously described in this chapter.

3.6.1 Program Inputs

The Life-365 program separates the input parameters into a few file menus that include the Structure, Scenarios and Analysis. The input parameters for associated costs are also found in these menus, but were not included in the analysis of this research report and were ignored.

Under the Structure menu, the user can define the parameters for the type of structure to be analyzed. The overall units selected were US units, the chloride concentration units were set to percent by weight of concrete and commercial trade names were selected for ease of comparisons. A one-dimensional chloride loading (slabs and walls) analysis was selected for the structure type to represent the field panels. The thickness was set to 6.0 inches with the rebar clear cover depth below the surface set to 1.5 inches. This is also the area of the Life-365 program that allows the user to define the mixture properties to be analyzed. This menu allows the user to input the desired water-to-cement ratio (w/cm) as well as the slag, class F fly ash and silica fume percentages to make up the total cementitious material contents. The rebar options selected were black steel with a total percentage of 1.8%.

The long-term exposure location was set to San Juan, Puerto Rico as the closest location comparable to Hawaii for temperatures (as there are no options for Hawaii), however, the average Honolulu harbor temperatures, as shown in Table 3-27, were used instead of the default temperatures and manually input under the detailed temperature section of the Structure menu for more accuracy. The marine tidal zone was selected for exposure type.

Under the exposure conditions (under the Structures menu) section, the maximum surface concentration was set to 0.8 percent by weight of concrete with 0.0 years to build up to this level (as the field panels were almost immediately submerged in the ocean) as previously described to be the recommended values by Life-365 for marine tidal zone exposures. The age of first exposure was set to 7 days as the field panels were set in the ocean after 7 days of casting. The month of first exposure varied per panel. Finally, the remaining economic parameter selections found in the Structure menu were not adjusted as they are not the focus of this research and do not influence the chloride infusion rate.

 

59 

Table 3-27: Average Monthly Honolulu Harbor Temperatures used for Life-365 Predictions.

Month Average Temperature (°F) January 73.3 February 74.3 March 74.7 April 76.7 May 78.0 June 80.3 July 81.7

August 82.7 September 81.5

October 80.5 November 78.0 December 75.5

 The Scenarios menu is another area of the Life-365 program that allows the user to define the mixture properties to be analyzed. In addition to inputting the desired water-to-cement ratios (w/cm), slag, class F fly ash and silica fume percentages as the previous menu, Life-365 allows the user to input generic or commercially named corrosion-inhibiting admixtures, which include Rheocrete CNI (referred to generically as “Calcium Nitrite Inhibitor”) and Rheocrete 222+ (referred to as “Amines & Esters”, which is the composition of the admixture). The DCI admixture is also combined as an option with the Rheocrete CNI admixture as it contains the same essential calcium nitrite parameters of that of CNI (see information previously discussed in Chapter 2). No analyses for FerroGard 901, Xpex Admix C-2000, latex and Kryton KIM admixtures were included in this research as they are not included in the Life-365 program. The remaining inputs in the Scenarios menu included selecting black steel for the rebar protection option (i.e. none) and selecting no barrier type.

3.6.2 Program Outputs

Life-365 calculates the chloride concentrations at any time, T, that the user desires (the calculate option is found within the Analysis menu) based on the inputs previously described. By default, the program automatically displays the outputs for the mixture being analyzed including the default diffusion coefficient at 28 days, D28, the diffusion decay index, m, the chloride threshold, Ct, and the time to corrosion propagation. The user is allowed to modify custom values for D28, m, Ct, and time to corrosion propagation. The concentration versus the depth of the specimen from the surface is graphed for either the corrosion initiation time or at any time the user desires (based on the options under the Analysis menu). Adjusted values in Life-365 were also graphed base on the user changes to D28, m and Ct. The data points from these graphs were then copied and plotted against the field panel chloride concentrations for comparison.

 

60 

3.7 Summary

This chapter referenced the concrete mixtures and proportions used to create both laboratory and field test specimens from the previous Phases II and III. The previous fabrication of the Phase III field panel specimens by Uno et al. (2004) used for analysis in this Phase IV study as well as the experimental procedures performed on each specimen for the chloride concentration chemical tests were described. An explanation of the Life-365 software set-up, inputs and outputs was also included.

 

61 

4 RESULTS OF FIELD PANELS AND LIFE-365 PREDICTIONS

4.1 Introduction

This chapter presents the results of the 2004, 2006 and 2008 field panel chloride concentrations with comparisons to the predicted values from the computer program Life-365. The comparisons in this chapter include the control, DCI, Rheocrete CNI, Rheocrete 222+, fly ash and silica fume. Currently there is no database in Life-365 for the remaining admixtures mentioned earlier in this report and they were therefore not analyzed. Proposed modifications to the default parameters in Life-365 were used to produce closer comparisons to the actual field panel readings and are presented in the following sections. Some of the comparisons for the 2008 samples have not been included in this report as sampling is still ongoing to date. The half cell readings and some photographs of the final field panel conditions are also included in this chapter for additional comparisons between the amount of chlorides in the concrete at the level of the steel to that of indications that corrosion either has or has not begun in the field panel specimen.

4.2 Life-365 Comparisons

The following figures in this section show the various chloride concentrations through the depth of each field panel specimen taken from the top, middle and bottom locations of each panel that again represent the dry, wet and fully submerged regions along the panel face, respectively. The Life-365 default plots along with the adjusted plots based on the recommended changes to the D28 and m parameters are also included within each figure. The chloride threshold values, Ct, were not modified as this parameter does not affect the diffusion rates, but were included for reference as they are used to indicate corrosion initiation time frames.

The Life-365 adjusted plots were modified using visual examination of the actual chloride concentrations found in the field panels. The best estimated fit for each plot was controlled by matching the Life-365 predicted chloride concentrations to that of the actual sampled results at the level of the steel (i.e. between 1.5 and 2.0 inches in from the surface). In the report by Uno et al. (2004), priority of fitting the plots was given to the test hole with the highest overall chloride concentrations. However, with the increased amount of data found in this report, an overall average trend between the top, middle and bottom test locations was held when determining the best fit for the adjustments needed in the predicted values.

Once a fit between the predicted and actual values was found to be satisfactory, the same adjusted values were used for all collection years of 2004, 2006 and 2008 for each appropriate comparable panel. The control panels 1 and 2 used the same adjusted parameters as they both contained mixtures with a 0.40 water-cement ratio. These same adjustment parameters from control panels 1 and 2 were also used for panels containing the admixtures DCI, Rheocrete CNI and Rheocrete 222+ since they were derived from these control panels with a 0.40 water-cement ratio, and are also not intended to modify the diffusion rates through the concrete. Control panel 7 used a different set of adjusted parameters as the water-cement ratio was set to 0.35. The panels containing fly ash and

 

62 

silica fume also had different adjusted parameters as they contained different cementitious constituents. Only a representative amount of plots are shown in this chapter. For all plots done in this report, refer to the appendix.

4.2.1 Concentrations and Predictions for Control Mixtures

The plots of all the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for control panel 1 are shown in Figure 4-1, Figure 4-2 and Figure 4-3. The plots of all the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for control panel 2 are shown in Figure 4-4, Figure 4-5 and Figure 4-6. The Life-365 default predictions overestimated the actual results for each panel. Adjustments were made by decreasing the diffusion coefficient and increasing the m variable. The default and adjusted values for all control panel 1 and control panel 2 plots are reported in Table 4-1.

Table 4-1: Default and Adjusted Input Values for Control Panels 1 and 2

Default values  Adjusted values 

Diffusion coefficient  7.94E‐12 5.50E‐12 

m  0.20 0.38 

Corrosion threshold  0.05 0.05 

Figure 4-1: Life-365 predictions for 2004 Control Panel 1.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 1 - Kapaa - Control (0.4 w/c)

Top (1.5 yrs)

Middle (1.5 yrs)

Bottom (1.6 yrs)

Life-365 (1.5 yrs)

Life-365 (1.5 yrs Adjusted)

 

63 

Figure 4-2: Life-365 predictions for 2006 Control Panel 1.

Figure 4-3: Life-365 predictions for 2008 Control Panel 1.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 1 - Kapaa - Control (0.4 w/c)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 1 - Kapaa - Control (0.4 w/c)Top (5.6 yrs)

Middle (5.6 yrs)

Bottom (5.6 yrs)

Life-365 (5.6 yrs)

Life-365 (5.6 yrs Adjusted)

 

64 

Figure 4-4: Life-365 predictions for 2004 Control Panel 2.

Figure 4-5: Life-365 predictions for 2006 Control Panel 2.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 2 - Halawa - Control (0.40 w/c)

Top (1.4 yrs)

Middle (1.4 yrs)

Bottom (1.7 yrs)

Life-365 (1.4 yrs)

Life-365 (1.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 2 - Halawa - Control (0.40 w/c)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

65 

Figure 4-6: Life-365 predictions for 2008 Control Panel 2.

The plots of all the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for control panel 7 are shown in Figure 4-7, Figure 4-8 and Figure 4-9. The Life-365 default predictions overestimated the actual results for each panel. Adjustments were made by increasing both the diffusion coefficient and the m variable. The default and adjusted values for all control panel 7 plots are reported in Table 4-2.

Table 4-2: Default and Adjusted Input Values for Control Panel 7

Default values  Adjusted values 

Diffusion coefficient  6.03E‐12 6.50E‐12 

m  0.20 0.53 

Corrosion threshold  0.05 0.05 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 2 - Halawa - Control (0.40 w/c)

Top (5.7 yrs)

Middle (5.7 yrs)

Bottom (5.7 yrs)

Life-365 (5.7yrs)

Life-365 (5.7 yrs Adjusted)

 

66 

Figure 4-7: Life-365 predictions for 2004 Control Panel 7.

Figure 4-8: Life-365 predictions for 2006 Control Panel 7.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 7 - Kapaa - Control (0.35 w/c)

Top (1.5 yrs)

Middle (1.5 yrs)

Bottom (1.7 yrs)

Life-365 (1.7 yrs)

Life-365 (1.7 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 7 - Kapaa - Control (0.35 w/c)Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

67 

Figure 4-9: Life-365 predictions for 2008 Control Panel 7.

4.2.2 Concentrations and Predictions for DCI Mixtures

The plots of the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for DCI panel 3 and DCI panel 4 at the 2006 collection date are shown in Figure 4-10 and Figure 4-11, respectively. As with the control panels, the Life-365 default predictions overestimated the actual results for each panel. The same adjustments as the control panels 1 and 2 were made by decreasing the diffusion coefficient and increasing the m variable. The default and adjusted values for all of the DCI panel plots are reported in Table 4-3.

Table 4-3: Default and Adjusted Input Values for all DCI Panels

Default values  Adjusted values 

Diffusion coefficient  7.94E‐12  5.50E‐12 

m  0.20  0.38 

Corrosion threshold  0.15 (2 gal/yd3); 0.32 (4 gal/yd3)  0.15 (2 gal/yd3); 0.32 (4 gal/yd3) 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 7 - Kapaa - Control (0.35 w/c)

Top (5.6 yrs)

Middle (5.6 yrs)

Bottom (5.6 yrs)

Life-365 (5.6 yrs)

Life-365 (5.6 yrs Adjusted)

 

68 

Figure 4-10: Life-365 predictions for 2006 DCI Panel 3.

Figure 4-11: Life-365 predictions for 2006 DCI Panel 4.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 3 - Kapaa - DCI (2 gal/yd3)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 4 - Halawa - DCI (2 gal/yd3)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

69 

4.2.3 Concentrations and Predictions for Rheocrete CNI Mixtures

The plots of the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for Rheocrete CNI panel 5A and Rheocrete CNI panel 6 at the 2008 collection date are shown in Figure 4-10 and Figure 4-11, respectively. As with the control panels, the Life-365 default predictions overestimated the actual results for each panel. The same adjustments as the control panels 1 and 2 were made by decreasing the diffusion coefficient and increasing the m variable. Default and adjusted values for all of the Rheocrete CNI panel plots are shown in Table 4-4.

Table 4-4: Default and Adjusted Input Values for all Rheocrete CNI Panels

Default values  Adjusted values 

Diffusion coefficient  7.94E‐12  5.50E‐12 

m  0.20  0.38 

Corrosion threshold  0.15 (2 gal/yd3); 0.32 (4 gal/yd3)  0.15 (2 gal/yd3); 0.32 (4 gal/yd3) 

Figure 4-12: Life-365 predictions for 2008 Rheocrete CNI Panel 5A.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5A - Kapaa - CNI (4 gal/yd3)

Top (4.7 yrs)

Middle (4.7 yrs)

Bottom (4.7 yrs)

Life-365 (4.7 yrs)

Life-365 (4.7 yrs Adjusted)

 

70 

Figure 4-13: Life-365 predictions for 2008 Rheocrete CNI Panel 6.

4.2.4 Concentrations and Predictions for Rheocrete 222+ Mixtures

The plots of the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for Rheocrete 222+ panel 16 and Rheocrete 222+ panel 17 at the 2006 collection date are shown in Figure 4-14 and Figure 4-15, respectively. As with the control panels, the Life-365 default predictions overestimated the actual results for each panel. The same adjustments as the control panels 1 and 2 were made by decreasing the diffusion coefficient and increasing the m variable. The default and adjusted values for all of the Rheocrete 222+ plots are reported in Table 4-5.

Table 4-5: Default and Adjusted Input Values for all Rheocrete 222+ Panels

Default values  Adjusted values 

Diffusion coefficient  7.94E‐12 5.50E‐12 

m  0.20 0.38 

Corrosion threshold  0.12 0.12 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 6 - Kapaa - CNI (2 gal/yd3)Top (5.3 yrs)

Middle (5.3 yrs)

Bottom (5.3 yrs)

Life-365 (5.3 yrs)

Life-365 (5.3 yrs Adjusted)

 

71 

Figure 4-14: Life-365 predictions for 2006 Rheocrete 222+ Panel 16.

Figure 4-15: Life-365 predictions for 2006 Rheocrete 222+ Panel 17.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 16 - Kapaa - Rheocrete 222+ (1 gal/yd3)

Top (3.3 yrs)

Middle (3.3 yrs)

Bottom (3.3 yrs)

Life-365 (3.3 yrs)

Life-365 (3.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 17 - Halawa - Rheocrete 222+ (1 gal/yd3)Top (3.3 yrs)

Middle (3.3 yrs)

Bottom (3.3 yrs)

Life-365 (3.3 yrs)

Life-365 (3.3 yrs Adjusted)

 

72 

4.2.5 Concentrations and Predictions for Fly Ash Mixtures

The plots of the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for fly ash panel 11 at the 2008 collection date and fly ash panel 12 at the 2006 collection date are shown in Figure 4-16 and Figure 4-17, respectively. The Life-365 default predictions overestimated the actual results for each panel. Adjustments for all fly ash panels were made by decreasing the diffusion coefficient and increasing the m variable. The default and adjusted values for all of the fly ash panel plots are reported in Table 4-6.

Table 4-6: Default and Adjusted Input Values for all Fly Ash Panels

Default values  Adjusted values 

Diffusion coefficient  6.37E‐12 3.00E‐12 

m  0.32 0.35 

Corrosion threshold  0.05 0.05 

Figure 4-16: Life-365 predictions for 2008 Fly Ash Panel 11.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 11 - Kapaa - Fly Ash (15%)Top (5.3 yrs)

Middle (5.3 yrs)

Bottom (5.3 yrs)

Life-365 (5.3 yrs)

Life-365 (5.3 yrs Adjusted)

 

73 

Figure 4-17: Life-365 predictions for 2006 Fly Ash Panel 12.

4.2.6 Concentrations and Predictions for Silica Fume Mixtures

The plots of the actual sampled results of the chloride concentrations with the default and adjusted Life-365 results for silica fume panel 8 at the 2008 collection date and silica fume panel 10 at the 2006 collection date are shown in Figure 4-18 and Figure 4-19, respectively. Unlike all other plots of the various mixtures, the Life-365 default predictions for silica fume only slightly overestimated the actual results for each panel. Adjustments for all silica fume panels were made by decreasing the diffusion coefficient and increasing the m variable. The default and adjusted values for all of the silica fume panel plots are reported in Table 4-7.

Table 4-7: Default and Adjusted Input Values for all Silica Fume Panels

Default values  Adjusted values 

Diffusion coefficient  2.71E‐12 2.50E‐12 

m  0.20 0.30 

Corrosion threshold  0.05 0.05 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 12 - Halawa - Fly Ash (15%)Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

74 

Figure 4-18: Life-365 predictions for 2008 Silica Fume Panel 8.

Figure 4-19: Life-365 predictions for 2006 Silica Fume Panel 10.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 8 - Kapaa - Silica Fume (5%)Top (5.2 yrs)

Middle (5.2 yrs)

Bottom (5.2 yrs)

Life-365 (5.2 yrs)

Life-365 (5.2 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 10 - Kapaa - Silica Fume (5%)

Top (2.9 yrs)

Middle (2.9 yrs)

Bottom (2.9 yrs)

Life-365 (2.9 yrs)

Life-365 (2.9 yrs Adjusted)

 

75 

4.3 Half-cell Potentials

A half-cell potential test was performed on each field panel at the various collection ages as this test gives a probabilistic determination of corrosion occurrence of the reinforcing steel found within the concrete specimen. Statistical probabilities for corrosion occurrence in the reinforced concrete are based on using a copper sulfate electrode (CSE) and are presented in Table 4-8. The half-cell potential tests performed in the field were done with a saturated calomel electrode (SCE) and the results were later converted to a copper sulfate electrode (CSE) by subtracting 77 mV.

Table 4-8: Corrosion Ranges for Half-cell Potential Test Results (V vs. CSE)

Measured Potential (mV)  Statistical risk of corrosion occurring 

<  ‐350  >90% 

Between ‐350 and ‐200  50% 

> ‐200  <10% 

4.3.1 Half-cell Results and Visual Observations for Control Panels

The final half-cell results for control panel 1 indicated a probability of over 90% corrosion occurring at the level of the reinforcing steel. A crack was also observed in further suggesting that corrosion has occurred. The half-cell readings along with the visual observations for control panel 1 are presented in Figure 4-20 and Figure 4-21, respectively.

The final half-cell results for control panel 2 indicated a probability of over 90% corrosion occurring at the level of the reinforcing steel. A few cracks with rust were also observed further confirming that corrosion has occurred. The half-cell readings along with the visual observations for control panel 2 are presented in Figure 4-22 and Figure 4-23, respectively.

The final half-cell results for control panel 7 indicated a probability of over 90% corrosion occurring at the level of the reinforcing steel. However, visual observations of appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for control panel 7 are presented in Figure 4-24 and Figure 4-25, respectively.

 

76 

Figure 4-20: Half-cell Potential Tests for Control Panel 1.

Figure 4-21: Final Visual Observations for Control Panel 1.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #1: Kapaa Control with 0.4 w/c ratio

2 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

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Crack Observed

 

77 

Figure 4-22: Half-cell Potential Tests for Control Panel 2.

Figure 4-23: Final Visual Observations for Control Panel 2.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #2: Halawa Control with 0.40 w/c ratio

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

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Rust Observed

 

78 

Figure 4-24: Half-cell Potential Tests for Control Panel 7.

Figure 4-25: Final Visual Observations for Control Panel 7.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #7: Kapaa Control with 0.35 w/c ratio

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

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79 

4.3.2 Half-cell Results and Visual Observations for DCI Panels

The final half-cell results for DCI panel 3 indicated a probability of less than 10% corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for DCI panel 3 are presented in Figure 4-26 and Figure 4-27, respectively.

The final half-cell results for DCI panel 4 indicated a probability of over 90% corrosion occurring at the level of the reinforcing steel. A crack with rust was also observed further confirming that corrosion has occurred. The half-cell readings along with the visual observations for DCI panel 4 are presented in Figure 4-28 and Figure 4-29, respectively.

 

80 

Figure 4-26: Half-cell Potential Tests for DCI Panel 3.

Figure 4-27: Final Visual Observations for DCI Panel 3.

0

50

100

150

200

250

300

350

400

450

Ave

rag

e H

alf

Ce

ll

(-0

.00

1m

V).

Distance from top of panel (cm)

Panel #3: Kapaa 0.40 w/c with DCI at 10l/m3 (2 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

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81 

Figure 4-28: Half-cell Potential Tests for DCI Panel 4.

Figure 4-29: Final Visual Observations for DCI Panel 4.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #7: Kapaa Control with 0.35 w/c ratio

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

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82 

4.3.3 Half-cell Results and Visual Observations for Rheocrete CNI Panels

The final half-cell results for Rheocrete CNI panel 5A indicated a probability in the range of 50% corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for Rheocrete CNI panel 5A are presented in Figure 4-30 and Figure 4-31, respectively.

The final half-cell results for Rheocrete CNI panel 6 gave mixed results between 50% and of over 90% probability of corrosion occurring at the level of the reinforcing steel. However, an area with rust was observed confirming that corrosion has occurred. The half-cell readings along with the visual observations for Rheocrete CNI panel 6 are presented in Figure 4-32 and Figure 4-33, respectively.

 

83 

Figure 4-30: Half-cell Potential Tests for Rheocrete CNI Panel 5A.

Figure 4-31: Final Visual Observations for Rheocrete CNI Panel 5A.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #5A: Kapaa 0.40 w/c with CNI at 20l/m3 (4 gal/cuyd)

1.1 years2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

Pro

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84 

Figure 4-32: Half-cell Potential Tests for Rheocrete CNI Panel 6.

Figure 4-33: Final Visual Observations for Rheocrete CNI Panel 6.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #6: Kapaa 0.40 w/c with CNI at 10 l/m3 (2 gal/cuyd)

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

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Rust Observed

 

85 

4.3.4 Half-cell Results and Visual Observations for Rheocrete 222+ Panels

The final half-cell results for Rheocrete 222+ panel 16 indicated a probability in the range of 50% to just at or below 90% corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for Rheocrete 222+ panel 16 are presented in Figure 4-34 and Figure 4-35, respectively.

The final half-cell results for Rheocrete 222+ panel 17 gave mixed results between 50% and of over 90% probability of corrosion occurring at the level of the reinforcing steel. However, an area with rust was observed confirming that corrosion has occurred. The half-cell readings along with the visual observations for Rheocrete 222+ panel 17 are presented in Figure 4-36 and Figure 4-37, respectively.

 

86 

Figure 4-34: Half-cell Potential Tests for Rheocrete 222+ Panel 16.

Figure 4-35: Final Visual Observations for Rheocrete 222+ Panel 16.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #16: Kapaa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

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87 

Figure 4-36: Half-cell Potential Tests for Rheocrete 222+ Panel 17.

Figure 4-37: Final Visual Observations for Rheocrete 222+ Panel 17.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #17: Halawa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

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Rust Observed

 

88 

4.3.5 Half-cell Results and Visual Observations for Fly Ash Panels

The final half-cell results for fly ash panel 11 indicated a probability in the range of 50% to just at or below 90% corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for fly ash panel 11 are presented in Figure 4-38 and Figure 4-39, respectively.

The final half-cell results for fly ash panel 12 indicated readings of just above 10% probability of corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for fly ash panel 12 are presented in Figure 4-40 and Figure 4-41, respectively.

 

89 

Figure 4-38: Half-cell Potential Tests for Fly Ash Panel 11.

Figure 4-39: Final Visual Observations for Fly Ash Panel 11.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #11: Kapaa 0.36 w/c with 15% Fly Ash

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

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90 

Figure 4-40: Half-cell Potential Tests for Fly Ash Panel 12.

Figure 4-41: Final Visual Observations for Fly Ash Panel 12.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #12: Halawa 0.36 w/c with 15% Fly Ash

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

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4.3.6 Half-cell Results and Visual Observations for Silica Fume Panels

The final half-cell results for silica fume panel 8 indicated a probability in the range of 50% to just below 90% corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for silica fume panel 8 are presented in Figure 4-42 and Figure 4-43, respectively.

Unlike the final half-cell results for silica fume panel 8, it was important to note that silica fume panel 9 indicated a probability of over 90% corrosion occurring at the level of the reinforcing steel. A crack with rust was also observed further confirming that corrosion has occurred. The half-cell readings along with the visual observations for fume panel 9 are presented in Figure 4-44 and Figure 4-45, respectively.

The final half-cell results for silica fume panel 10 indicated readings of 50% probability of corrosion occurring at the level of the reinforcing steel. Visual observations appeared to give no indication of corrosion occurring to date. The half-cell readings along with the visual observations for silica fume panel 10 are presented in Figure 4-46 and Figure 4-47, respectively.

 

92 

Figure 4-42: Half-cell Potential Tests for Silica Fume Panel 8.

Figure 4-43: Final Visual Observations for Silica Fume Panel 8.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #8: Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

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Figure 4-44: Half-cell Potential Tests for Silica Fume Panel 9.

Figure 4-45: Final Visual Observations for Silica Fume Panel 9.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #9: Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)

1.1 years2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

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Rust Observed

 

94 

Figure 4-46: Half-cell Potential Tests for Silica Fume Panel 10.

Figure 4-47: Final Visual Observations for Silica Fume Panel 10.

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #10: Kapaa 0.36 w/c with 5% Silica Fume (Grace)

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

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4.4 Summary

This chapter presented various chloride concentrations for actual field panel samples as well as default and adjusted prediction values from the computer program Life-365. All of the default predicted values for Life-365 for all mixtures overestimated the actual sampled concentrations through the depths of each specimen. Adjusted parameters to the Life-365 software included a general trend to decrease the diffusion coefficients and increase the m variable to get a comparable fit to the actual chloride concentration results with a focus on the 1.5 and 2.0 inch depths. Final half-cell results were presented along with a visual observation of each corresponding panel to validate the indications of corrosion occurring in each reinforced concrete field panel.

 

96 

 

97 

5 CONCLUSIONS

Based on the results of this study of 25 reinforced concrete panels exposed to the tidal zone in Honolulu Harbor for 10 years, the following conclusions were drawn:

The control panel comprised of the Kapaa aggregates with a water‐cement ratio of 0.35 exhibited a lower rate of chloride ion ingress than the control panels with a 0.40 water‐cement ratio. 

Panels with the 0.40 water‐cement ratio were noted to have cracks induced by corrosion of the reinforcing steel as well as rust residue on the surface after 7 years of exposure. 

The corrosion inhibiting admixtures DCI, Rheocrete CNI, and Rheocrete 222+ did not reduce the chloride penetration rate when compared to the control as these admixtures were intended to directly protect the steel from corrosion and not necessarily reduce permeability.  

The pozzolanic admixture materials, fly ash and silica fume, performed the best for reducing the chloride ion penetration rates through the concrete specimens. 

Life‐365 software default predictions overestimated the chloride concentrations when compared to the actual results of the control panels as well as those panels including DCI, Rheocete CNI, and Rheocrete 222+ and need to be modified to better predict the actual chloride concentrations with emphasis at the level of the reinforcing steel. 

Life‐365 software default parameters for fly ash were closer than the control panels and chemical corrosion inhibiting admixtures.  However, modifications were still needed as the software still overestimated the chloride concentrations. 

Life‐365 best predicted the chloride concentrations for the silica fume admixture as very little modification to the program’s default parameters was necessary.  Only a slight adjustment was required to the Life‐365 default parameters. 

The calcium nitrite type admixtures, DCI and Rheocrete CNI, appeared to be most effective with a dosage of 4 gal/yd3 as the lower dosage of 2 gal/yd3 produced inconsistent results for corrosion protection. The final half‐cell readings and visual observations demonstrated the effectiveness of the greater dosage. 

The final half‐cell readings and visual observations for Rheocrete 222+ demonstrated inconsistent results for corrosion initiation. 

The panels with 15% cement replacement with fly ash gave the most consistent results when considering chloride concentrations, final half‐cell readings and visual observations. These panels demonstrated good performance with no visual signs of corrosion. 

Panels with 5% cement replaced with silica fume showed good performance except for one panel where it appeared that poor dispersion of the silica fume during mixing led to pockets of silica fume powder in the final specimen. 

The panel using 2% Kryton Kim performed well during the field exposure, with low half‐cell readings and no visible signs of corrosion after 10 years exposure. 

Panels using the remaining admixtures, FerroGard 901, Xypex Admix C‐2000 and latex modifier exhibited inconsistent to poor results. 

 

98 

 

 

99 

6 RESEARCH PROJECT PUBLICATIONS

6.1 Research Reports (Copies available online)

Ropert, J., and Robertson, I.N. (2012). Prediction of Chloride Penetration Rates in Hawaiian Concrete in a Marine Environment. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CEE/12-02.

Available at: http://www.cee.hawaii.edu/reports/UHM-CEE-12-02.pdf Cheng, H., and Robertson, I. N. (2006). Performance of Admixtures Intended to Resist

Corrosion in Concrete Exposed to a Marine Environment. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CEE/06-08.

Available at: http://www.cee.hawaii.edu/reports/UHM-CEE-06-08.pdf Kakuda, D., Robertson, I. N., and Newtson, C. M. (2005). Evaluation of Non-Destructive

Techniques for Corrosion Detection in Concrete Exposed to a Marine Environment. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CEE/05-04.

Available at: http://www.eng.hawaii.edu/~ian/Kakuda.pdf Okunaga, G. J., Robertson, I. N., and Newtson, C. M. (2005). Laboratory Study of

Concrete Produced With Admixtures Intended to Inhibit Corrosion. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CEE/05-05.

Available at: http://www.cee.hawaii.edu/reports/UHM-CEE-05-05.pdf Uno, J., Robertson, I. N., and Newtson, C.M. (2004). Corrosion Susceptibility of

Concrete Exposed To A Marine Environment. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CEE/04-09.

Available at: http://www.cee.hawaii.edu/reports/UHM-CEE-04-09.pdf

6.2 Conference Publications (Copies provided in Appendix C)

Robertson, I.N., Improving Concrete Durability through the use of Corrosion Inhibitors, Proceedings of the 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, Cape Town, South Africa, September 3-5, 2012.

Robertson, I.N., Prediction of Chloride Ingress into Concrete in a Marine Environment, SCSS 2012, Proceedings of Strategies for Sustainable Concrete Structures, Aix-en-Provence, France, May 29 – June 1, 2012.

Robertson, I.N., and Newtson, C., Improving Concrete Durability through use of Corrosion Inhibitors, Proceedings of the IABSE-IASS 2011 Symposium, London, England, Sept. 20-23, 2011.

 

100 

Robertson, I.N., and Newtson, C., Performance of Corrosion Inhibitors in Concrete Exposed to Marine Environment, Proceedings of the International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR2008, Cape Town, South Africa, Nov. 24-26, 2008.

6.3 Conference and Seminar Presentations

8. Robertson, I.N., Concrete Durability – Hawaii Study, CCPI Annual Meeting, Wailea, Maui, Oct. 7, 2011

9. Robertson, I.N., Concrete Durability Enhancement through use of Corrosion Inhibitors, Hawaii DOT Harbors Division, Honolulu, Hawaii, Sept. 27, 2011

10. Robertson, I.N., Concrete Durability Research, CCPI-SEAOH Convention, Waikiki, Honolulu, Oct. 16, 2009.

11. Robertson, I.N., Improved Durability of Coastal Infrastructure Subjected to Corrosion, Research Seminar by Faculty, Saitama University, Saitama, Japan, July 30, 2009.

12. Robertson, I.N., Update on corrosion studies, Construction Specifications Institute seminar, Honolulu, Hawaii, August 21, 2007.

 

101 

 7 OTHER REFERENCES

ACI Committee 201. (2001). Guide to Durable Concrete, ACI 201.2R-01, American Concrete Institute.

ACI Committee 222. (2001). Protection of Metals in Concrete Against Corrosion, ACI

222R-01, American Concrete Institute. ACI Committee 318. (2008). Building Code Requirements for Structural Concrete (318-

08) and Commentary (318R-08), American Concrete Institute. BASF Construction Chemicals. (2007). “Rheocrete CNI Corrosion Inhibiting

Admixture”. Product Data Sheet. BASF Construction Chemicals, LLC. Retrieved from http://www.basf-admixtures.com

BASF Construction Chemicals. (2007). “Rheocrete 222+ Corrosion Inhibiting

Admixture”. Product Data Sheet. BASF Construction Chemicals, LLC. Retrieved from http://www.basf-admixtures.com

BASF Construction Chemicals. (2007). “Rheomac SF 100 Densified Silica Fume Mineral

Admixture”. Product Data Sheet. BASF Construction Chemicals, LLC. Retrieved from http://www.basf-admixtures.com

Bola, M., and Newtson, C. M. (2000). Field Evaluation of Corrosion in Reinforced

Concrete Structures in Marine Environment. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CE/00-01.

Brady, J. E., and Senese, F. (2004). Chemistry: Matter and Its Changes (4th ed.).

Hoboken, NJ: John Wiley & Sons, Inc. Concrete Technology. (2011). Durability: Corrosion of Embedded Metals. Portland

Cement Association. Retrieved from http://www.cement.org/tech/cct_dur_corrosion.asp

Diamond, S., and Sheng, Q. (1989). Laboratory Investigations on Latex-Modified

Concrete. Joint Highway Research Project, Indiana Department of Transportation and Purdue University. Publication FHWA/IN/JHRP-89/15-1.

Koch, G. H., Brongers, M. P. H., and Thompson, N. G. (2001). Corrosion Costs and

Preventative Strategies in the United States. U.S. Department of Transportation Federal Highway Administration. Publication No. FHWA-RD-01-156, Federal Highway Administration.

 

102 

Federal Highway Administration. (2011). Fly Ash. U.S. Department of Transportation Federal Highway Administration. Retrieved from http://www.fhwa.dot.gov/infrastructure/materialsgrp/flyash.htm

Kryton International. (2011). “Krystol Internal Membrane (KIM) Waterproofing

Admixture for Concrete”. Technical Data Sheet. Kryton International, Inc. Retrieved from http://www.kryton.com

Li, L., and Sagues, A. A. (2001). Metallurgical Effects on Chloride Ion Corrosion

Threshold of Steel in Concrete. Department of Civil and Environmental Engineering, University of South Florida. Research Report WPI 0510806.

Life-365. (2012). Life-365 Service Life Prediction Model and Computer Program for

Predicting the Service Life and Life-Cycle Cost of Reinforced Concrete Exposed to Chlorides. Version 2.1 User’s Manual by Ehlen, M. A., Life-365 Consortium II.

McMurry, J., and Fay, R. C. (2001). Chemistry (3rd ed.). Upper Saddle River, NJ:

Prentice-Hall, Inc. Paradise, L. A., Petechuck, D., and Mertz, L. (2003). “Is fly ash an inferior building and

structural material”. Science in Dispute. Volume 2. Retrieved from http://findarticles.com

Pham, P. A., and Newtson, C. M. (2001). Properties of Concrete Produced with

Admixtures Intended to Inhibit Corrosion. Department of Civil and Environmental Engineering, University of Hawaii at Manoa. Research Report UHM/CEE/01-01.

Sika (2008). “Sika FerroGard 901 Corrosion Inhibiting Admixture”. Product Data Sheet.

Sika Corporation. Retrieved from http://usa.sika.com Smith, J. L., and Virmani, Y. P. (2000). Materials and Methods for Corrosion Control of

Reinforced and Prestressed Concrete Structures in New Construction. Federal Highway Administration. Report FHWA-RD-00-081.

Vector Corrosion Technologies. (2009). Corrosion Basics. Retrieved from

http://www.vector-corrosion.com/education-2/corrosion/ W.R. Grace & Co.-Conn. (2007). “DCI Corrosion Inhibitor”. Product Data Sheet. W.R.

Grace & Co.-Conn. Retrieved from http://www.graceconstruction.com W.R. Grace & Co.-Conn. (2010). “Force 10,000 D High Performance Concrete

Admixture Dry Densified Powder”. Product Data Sheet. W.R. Grace & Co.-Conn. Retrieved from http://www.graceconstruction.com

Xypex Chemical Corporation. (2004). “Xypex Admix C-2000”. Product Data Sheet.

Xypex Chemical Corporation. Retrieved from http://www.xypex.com

 

103 

8 APPENDIX B

Chloride concentration plots for all field panels

 

104 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 1 - Kapaa - Control (0.4 w/c)

Top (1.5 yrs)

Middle (1.5 yrs)

Bottom (1.6 yrs)

Life-365 (1.5 yrs)

Life-365 (1.5 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 1 - Kapaa - Control (0.4 w/c)Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

105 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 1 - Kapaa - Control (0.4 w/c)Top (5.6 yrs)

Middle (5.6 yrs)

Bottom (5.6 yrs)

Life-365 (5.6 yrs)

Life-365 (5.6 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 2 - Halawa - Control (0.40 w/c)

Top (1.4 yrs)

Middle (1.4 yrs)

Bottom (1.7 yrs)

Life-365 (1.4 yrs)

Life-365 (1.4 yrs Adjusted)

 

106 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 2 - Halawa - Control (0.40 w/c)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 2 - Halawa - Control (0.40 w/c)Top (5.7 yrs)

Middle (5.7 yrs)

Bottom (5.7 yrs)

Life-365 (5.7yrs)

Life-365 (5.7 yrs Adjusted)

 

107 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 3 - Kapaa - DCI (2 gal/yd3)Top (1.7 yrs)

Middle (1.7 yrs)

Bottom (1.7 yrs)

Life-365 (1.7 yrs)

Life-365 (1.7 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 3 - Kapaa - DCI (2 gal/yd3)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

108 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 3A - Kapaa - DCI (4 gal/yd3)

Top (0.7 yrs)

Middle (0.2 yrs)

Bottom (0.6 yrs)

Life-365 (0.6 yrs)

Life-365 (0.6 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 3A - Kapaa - DCI (4 gal/yd3)

Top (2.5 yrs)

Middle (2.5 yrs)

Bottom (2.5 yrs)

Life-365 (2.5 yrs)

Life-365 (2.5 yrs Adjusted)

 

109 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 4 - Halawa - DCI (2 gal/yd3)Top (1.8 yrs)

Middle (1.8 yrs)

Bottom (1.8 yrs)

Life-365 (1.8 yrs)

Life-365 (1.8 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 4 - Halawa - DCI (2 gal/yd3)Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

 

110 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5 - Kapaa - CNI (2 gal/yd3)Top (1.6 yrs)

Middle (1.6 yrs)

Bottom (1.7 yrs)

Life-365 (1.6 yrs)

Life-365 (1.6 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5 - Kapaa - CNI (2 gal/yd3)

Top (3.3 yrs)

Middle (3.3 yrs)

Bottom (3.3 yrs)

Life-365 (3.3 yrs)

Life-365 (3.3 yrs Adjusted)

 

111 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5 - Kapaa - CNI (2 gal/yd3)Top (5.5 yrs)

Middle (5.5 yrs)

Bottom (5.5 yrs)

Life-365 (5.5 yrs)

Life-365 (5.5 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5A - Kapaa - CNI (4 gal/yd3)

Top (0.2 yrs)

Middle (0.2 yrs)

Bottom (0.6 yrs)

Life-365 (0.6 yrs)

Life-365 (0.6 yrs Adjusted)

 

112 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5A - Kapaa - CNI (4 gal/yd3)Top (2.5 yrs)

Middle (2.5 yrs)

Bottom (2.5 yrs)

Life-365 (2.5 yrs)

Life-365 (2.5 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 5A - Kapaa - CNI (4 gal/yd3)

Top (4.7 yrs)

Middle (4.7 yrs)

Bottom (4.7 yrs)

Life-365 (4.7 yrs)

Life-365 (4.7 yrs Adjusted)

 

113 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 6 - Kapaa - CNI (2 gal/yd3)Top (1.1 yrs)

Middle (1.1 yrs)

Bottom (1.3 yrs)

Life-365 (1.3 yrs)

Life-365 (1.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 6 - Kapaa - CNI (2 gal/yd3)

Top (3.1 yrs)

Middle (3.1 yrs)

Bottom (3.1 yrs)

Life-365 (3.1 yrs)

Life-365 (3.1 yrs Adjusted)

 

114 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 6 - Kapaa - CNI (2 gal/yd3)Top (5.3 yrs)

Middle (5.3 yrs)

Bottom (5.3 yrs)

Life-365 (5.3 yrs)

Life-365 (5.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 7 - Kapaa - Control (0.35 w/c)

Top (1.5 yrs)

Middle (1.5 yrs)

Bottom (1.7 yrs)

Life-365 (1.7 yrs)

Life-365 (1.7 yrs Adjusted)

 

115 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 7 - Kapaa - Control (0.35 w/c)Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 7 - Kapaa - Control (0.35 w/c)Top (5.6 yrs)

Middle (5.6 yrs)

Bottom (5.6 yrs)

Life-365 (5.6 yrs)

Life-365 (5.6 yrs Adjusted)

 

116 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 8 - Kapaa - Silica Fume (5%)

Top (0.7 yrs)

Middle (0.7 yrs)

Bottom (1.3 yrs)

Life-365 (1.3 yrs)

Life-365 (1.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 8 - Kapaa - Silica Fume (5%)Top (2.9 yrs)

Middle (2.9 yrs)

Bottom (2.9 yrs)

Life-365 (2.9 yrs)

Life-365 (2.9 yrs Adjusted)

 

117 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 8 - Kapaa - Silica Fume (5%)Top (5.2 yrs)

Middle (5.2 yrs)

Bottom (5.2 yrs)

Life-365 (5.2 yrs)

Life-365 (5.2 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 9 - Kapaa - Silica Fume (5%)Top (0.4 yrs)

Middle (0.4 yrs)

Bottom (0.7 yrs)

Life-365 (0.7 yrs)

Life-365 (0.7 yrs Adjusted)

 

118 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 9 - Kapaa - Silica Fume (5%)

Top (2.5 yrs)

Middle (2.5 yrs)

Bottom (2.5 yrs)

Life-365 (2.5 yrs)

Life-365 (2.5 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 9 - Kapaa - Silica Fume (5%)Top (4.7 yrs)

Middle (4.7 yrs)

Bottom (4.7 yrs)

Life-365 (4.7 yrs)

Life-365 (4.7 yrs Adjusted)

 

119 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 10 - Kapaa - Silica Fume (5%)

Top (0.9 yrs)

Middle (0.9 yrs)

Bottom (0.7 yrs)

Life-365 (0.9 yrs)

Life-365 (0.9 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 10 - Kapaa - Silica Fume (5%)Top (2.9 yrs)

Middle (2.9 yrs)

Bottom (2.9 yrs)

Life-365 (2.9 yrs)

Life-365 (2.9 yrs Adjusted)

 

120 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 11 - Kapaa - Fly Ash (15%)

Top (1.1 yrs)

Middle (1.1 yrs)

Bottom (1.3 yrs)

Life-365 (1.3 yrs)

Life-365 (1.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 11 - Kapaa - Fly Ash (15%)

Top (3.1 yrs)

Middle (3.1 yrs)

Bottom (3.1 yrs)

Life-365 (3.1 yrs)

Life-365 (3.1 yrs Adjusted)

 

121 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 11 - Kapaa - Fly Ash (15%)

Top (5.3 yrs)

Middle (5.3 yrs)

Bottom (5.3 yrs)

Life-365 (5.3 yrs)

Life-365 (5.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 12 - Halawa - Fly Ash (15%)Top (1.3 yrs)

Middle (1.3 yrs)

Bottom (1.7 yrs)

Life-365 (1.3 yrs)

Life-365 (1.3 yrs Adjusted)

 

122 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 12 - Halawa - Fly Ash (15%)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 13 - Halawa - Fly Ash (15%)Top (1.4 yrs)

Middle (1.5 yrs)

Bottom (1.6 yrs)

Life-365 (1.4 yrs)

Life-365 (1.4 yrs Adjusted)

 

123 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 13 - Halawa - Fly Ash (15%)Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

Life-365 (3.4 yrs)

Life-365 (3.4 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 14 - Kapaa - Latex (5%)

Top (0.3 yrs)

Middle (0.3 yrs)

Bottom (0.7 yrs)

 

124 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 14 - Kapaa - Latex (5%)

Top (2.5 yrs)

Middle (2.5 yrs)

Bottom (2.5 yrs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 15 - Kapaa - Rheocrete 222+ (1 gal/yd3)Top (1.1 yrs)

Middle (1.1 yrs)

Bottom (1.4 yrs)

Life-365 (1.1 yrs)

Life-365 (1.1 yrs Adjusted)

 

125 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 15 - Kapaa - Rheocrete 222+ (1 gal/yd3)Top (3.3 yrs)

Middle (3.3 yrs)

Bottom (3.3 yrs)

Life-365 (3.3 yrs)

Life-365 (3.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 16 - Kapaa - Rheocrete 222+ (1 gal/yd3)

Top (1.4 yrs)

Middle (1.4 yrs)

Bottom (1.7 yrs)

Life-365 (1.7 yrs)

Life-365 (1.7 yrs Adjusted)

 

126 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 16 - Kapaa - Rheocrete 222+ (1 gal/yd3)

Top (3.3 yrs)

Middle (3.3 yrs)

Bottom (3.3 yrs)

Life-365 (3.3 yrs)

Life-365 (3.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 17 - Halawa - Rheocrete 222+ (1 gal/yd3)

Top (1.1 yrs)

Middle (1.1 yrs)

Bottom (1.5 yrs)

Life-365 (1.1 yrs)

Life-365 (1.1 yrs Adjusted)

 

127 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 17 - Halawa - Rheocrete 222+ (1 gal/yd3)

Top (3.3 yrs)

Middle (3.3 yrs)

Bottom (3.3 yrs)

Life-365 (3.3 yrs)

Life-365 (3.3 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 17A - Halawa - Rheocrete 222+ (1 gal/yd3)Top (0.4 yrs)

Middle (0.4 yrs)

Bottom (0.7 yrs)

Life-365 (0.7 yrs)

Life-365 (0.7 yrs Adjusted)

 

128 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 17A - Halawa - Rheocrete 222+ (1 gal/yd3)Top (2.5 yrs)

Middle (2.5 yrs)

Bottom (2.5 yrs)

Life-365 (2.5 yrs)

Life-365 (2.5 yrs Adjusted)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 18 - Halawa - FerroGard 901 (3 gal/yd3)

Top (1.3 yrs)

Middle (1.4 yrs)

Bottom (1.7 yrs)

 

129 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 18 - Halawa - FerroGard 901 (3 gal/yd3)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 19 - Halawa - FerroGard 901 (3 gal/yd3)

Top (1.4 yrs)

Middle (1.4 yrs)

Bottom (1.2 yrs)

 

130 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 19 - Halawa - FerroGard 901 (3 gal/yd3)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 20 - Kapaa - FerroGard 901 (3 gal/yd3)

Top (1.2 yrs)

Middle (1.2 yrs)

Bottom (1.2 yrs)

 

131 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 20 - Halawa - FerroGard 901 (3 gal/yd3)

Top (3.4 yrs)

Middle (3.4 yrs)

Bottom (3.4 yrs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 21 - Kapaa - Xypex Admix C-2000 (2%)

Top (1.4 yrs)

Middle (1.4 yrs)

Bottom (1.3 yrs)

 

132 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 21 - Kapaa - Xypex Admix C-2000 (2%)

Top (3.1 yrs)

Middle (3.1 yrs)

Bottom (3.1 yrs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 22 - Kapaa - Kryton KIM (2%)

Top (0.7 yrs)

Middle (0.7 yrs)

Bottom (0.2 yrs)

 

133 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5

Aci

d-so

lubl

e ch

lorid

e (%

by

wt

of c

oncr

ete)

Depth (in.)

Panel 22 - Kapaa - Kryton KIM (2%)

Top (2.5 yrs)

Middle (2.5 yrs)

Bottom (2.5 yrs)

 

134 

 

135 

9 APPENDIX B

Field panel half-cell readings with visual observations

0

50

100

150

200

250

300

350

400

450

Ave

rag

e H

alf

Ce

ll

(-0

.00

1m

V).

Distance from top of panel (cm)

Panel #1: Kapaa Control with 0.4 w/c ratio

2 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Crack Observed

 

136 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #2: Halawa Control with 0.40 w/c ratio

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed

 

137 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #3: Kapaa 0.40 w/c with DCI at 10l/m3 (2 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

138 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #3A: Kapaa 0.40 w/c with DCI at 20l/m3 (4 gal/cuyd)

1.1 years2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

139 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #4: Halawa 0.40 w/c with DCI at 10l/m3 (2 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed

 

140 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #5: Kapaa 0.40 w/c with CNI at 10l/m3 (2 gal/cuyd)

2.0 years

3.4 years

4.1 years

4.5 years

5.2 years

5.6 years

7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

141 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #6: Kapaa 0.40 w/c with CNI at 10 l/m3 (2 gal/cuyd)

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed

 

142 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #7: Kapaa Control with 0.35 w/c ratio

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

143 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #8: Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

144 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #9: Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)

1.1 years2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed

 

145 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #10: Kapaa 0.36 w/c with 5% Silica Fume (Grace)

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

146 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #11: Kapaa 0.36 w/c with 15% Fly Ash

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years6.7 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

147 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #12: Halawa 0.36 w/c with 15% Fly Ash

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

148 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #13: Halawa 0.36 w/c with 15% Fly Ash

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

149 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #14: Kapaa 0.40 w/c with 5% Latex Modifier

2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed

 

150 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #15: Kapaa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bili

ty o

f co

rros

ion

.

19 110886542 133

Rust Observed

 

151 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #16: Kapaa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bili

ty o

f co

rros

ion

.

19 110886542 133

 

152 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #17: Halawa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bili

ty o

f co

rros

ion

.

19 110886542 133

Rust Observed

 

153 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #17A: Halawa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd)

1.1 years2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

154 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #18: Halawa 0.40 w/c with Ferrogard at 15 l/m3 (3 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bilit

y o

f co

rro

sio

n.

19 110886542 133

Rust Observed

 

155 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #19: Halawa 0.40 w/c with Ferrogard at 15 l/m3 (3 gal/cuyd)

2.0 years3.4 years4.1 years4.5 years5.2 years5.6 years7.0 years

< 10%

> 90%

50%

Pro

ba

bilit

y o

f co

rro

sio

n.

19 110886542 133

Rust Observed

 

156 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #20: Kapaa 0.40 w/c with Ferrogard at 15 l/m3 (3 gal/cuyd)

3.1 years

3.8 years

4.2 years

5.0 years

5.3 years

6.7 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed

 

157 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #21: Kapaa 0.40 w/c with 2% Xypex

1.7 years3.1 years3.8 years4.2 years5.0 years5.3 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

Rust Observed after 7 years

 

158 

0

50

100

150

200

250

300

350

400

450A

vera

ge

Ha

lf C

ell

(-

0.0

01

mV

).

Distance from top of panel (cm)

Panel #22: Kapaa 0.40 w/c with 2% Kryton KIM

1.1 years2.4 years3.2 years3.6 years4.3 years4.8 years6.2 years

< 10%

> 90%

50%

Pro

ba

bil

ity

of

co

rro

sio

n.

19 110886542 133

 

159 

10 APPENDIX C

This appendix contains copies of the following publications related to this project:   1) Robertson, I.N., Improving Concrete Durability through the use of Corrosion

Inhibitors, Proceedings of the 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, Cape Town, South Africa, September 3-5, 2012.

2) Robertson, I.N., Prediction of Chloride Ingress into Concrete in a Marine

Environment, SCSS 2012, Proceedings of Strategies for Sustainable Concrete Structures, Aix-en-Provence, France, May 29 – June 1, 2012.

3) Robertson, I.N., and Newtson, C., Improving Concrete Durability through use of

Corrosion Inhibitors, Proceedings of the IABSE-IASS 2011 Symposium, London, England, Sept. 20-23, 2011.

4) Robertson, I.N., and Newtson, C., Performance of Corrosion Inhibitors in Concrete

Exposed to Marine Environment, Proceedings of the International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR2008, Cape Town, South Africa, Nov. 24-26, 2008.