Corrosion Resistant Alloys for Reinforced Concrete
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Initial cost considerations have historically precluded widespread utilization of high performance
(corrosion resistant) reinforcements such as stainless steels in bridge construction. However,
with the advent of life-cycle cost analysis as a project planning tool and of a requirement that
major bridge structures have a 75- to 100-year design life, the competitiveness of such steels has
increased such that enhanced attention has focused in recent years upon these materials.
This investigation was initiated to evaluate the corrosion resistance of various types of corrosion
resistant reinforcement, including new products that are becoming available, in bridge structures
that are exposed to chlorides. Both long-term (4-year) test yard exposures and accelerated
laboratory experiments in simulated concrete pore waters are being performed. The ultimate
objective is to, first, evaluate the corrosion properties and rank the different candidate materials
and, second, develop tools whereby long-term performance in actual structures can be projected
from short-term tests. This interim report presents results from the initial 3 years of an overall
5-year program.
Gary L. Henderson Director, Office of Infrastructure Research and Development
This document is disseminated under the sponsorship of the U. S. Department of Transportation
in the interest of information exchange. The U. S. Government and the State of Florida assume
no liability for its content or use thereof. This Report does not constitute a standard,
specification, or regulation.
The U. S. Government and the State of Florida do not endorse products or manufacturers. Trade
and manufacturers’ names appear in this report only because they are considered essential to the
objective of this document.
Quality Assurance Statement
The Federal Highway Administration (FHWA) provides high-quality information to serve
Government, industry, and the public in a manner that promotes public understanding. Standards
and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its
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ensure continuous quality improvement.
Technical Report Documentation Page
1. Report No. FHWA-HRT-07-039 |
2. Government Accession No. | 3. Recipient’s Catalog No. |
4. Title and Subtitle Corrosion Resistant Alloys for Reinforced Concrete | 5. Report Date July 2007 |
6. Performing Organization Code FAU-OE-CMM-0601 |
7.Author(s)
William H. Hartt,* Rodney G. Powers,** Diane K. Lysogorski,* Virginie Liroux,* Y. Paul Virmani*** (See Boxes 9 and 12) |
8. Performing Organization Report No. |
9. Performing Organization Name and Address *Florida Atlantic University–Sea Tech Campus, 101 North. Beach Road, Dania Beach, FL 33004 **Florida Department of Transportation–State Materials Office, 5007 NE 39th Street, Gainesville, FL 32609 | 10. Work Unit No. (TRAIS)
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11. Contract or Grant No. |
12. Sponsoring Agency Name and Address ***Office of Infrastructure Research and Development Federal Highway Administration 6300 Georgetown Pike McLean, VA 22012 | 13. Type of Report and Period Covered Interim Report |
14. Sponsoring Agency Code
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15. Supplementary Notes Contracting Officer’s Technical Representative (COTR): Y.P. Virmani, HRDI-10 |
16. Abstract Infrastructure deterioration, which includes corrosion of reinforcing steel in concrete bridges, has been identified as a major
economic and societal cost to the United States. For the past 30 years, epoxy-coated reinforcing steel (ECR) has been specified for reinforced concrete bridges exposed to deicing salts and coastal environments. Premature corrosion induced cracking of marine bridge substructures in Florida indicated, however, that ECR is of little benefit for this type of exposure; and while performance of ECR in northern bridge decks has been generally good to-date (30-plus years), still the degree of
corrosion resistance to be afforded in the long term to major structures with design lives of 75 to 100 years is uncertain. This concern, combined with increased utilization of life-cycle cost analysis in project planning and materials selection, has caused renewed interest in corrosion resistant reinforcements, stainless steels in particular. The present research study is being performed jointly by Florida Atlantic University and the Florida Department of Transportation to evaluate alloys that
have been identified as candidate corrosion resistant reinforcements. These include MMFX-II™ (ASTM A 1035), solid stainless steels 3Cr12 (UNS-S41003), 2201LDX (ASTM A955-98), 2205 (UNS 31803), and two 316L (UNS S31603) alloys; and two 316 stainless steel clad black bar products. Black bar (ASTM A615) reinforcement was included for comparison purposes. Testing methods included three types of short-term exposures: (1) a previously developed method that involves cyclic exposure to synthetic pore solution (SPS) with incrementally increasing chlorides and then to moist air, (2) anodic potentiostatic exposure in SPS with incrementally increasing chlorides, and (3) potentiodynamic polarization scans in
saturated Ca(OH)2 at different chloride concentrations. Long-term exposures involve four specimen types: (1) simulated deck slabs, (2) 3-bar columns, (3) macro-cell slab specimens, and (4) field columns. Specimen types (1) and (3) are being cyclically wet-dry ponded with a sodium chloride (NaCl) solution and are intended to simulate northern bridge decks exposed to deicing salts, whereas types (2) and (4) are partially submerged continuously, the former in a NaCl solution and the latter at a coastal marine site in Florida. This report details findings for the initial 3 years of this 5 year project. |
17. Key Word
Reinforced concrete, bridges, corrosion resistance, corrosion testing, high performance reinforcement, stainless steel, MMFX-II™ | 18. Distribution Statement
No restrictions. This document is available to the public through the NTIS, Springfield, VA 22161. |
19. Security Classif. (of this report) Unclassified | 20. Security Classif. (of this page) Unclassified | 21. No. of Pages 132 | 22. Price |
Form DOT F 1700.7 (8-72) | Reproduction of completed page authorized. |
Metric Conversion Chart
TABLE OF CONTENTS
1. INTRODUCTION
2. PROJECT OBJECTIVES
3. EXPERIMENTAL PROCEDURE
ACCELERATED SCREENING TESTS
General
Materials
AST-1: Wet-Dry Exposures
Specimens
Test Procedure AST-2A: Chloride Threshold Determinations AST-2B: Pitting Potential Determinations Specimens
Test Procedure
LONG-TERM TESTS
Specimen Design
General
Simulated Deck Slabs
Three Bar Columns
Macro-Cell Slab Specimens
Field Columns
4. EXPERIMENTAL RESULTS AND DISCUSSION
SIMULATED PORE WATER PH DATA FOR AST-1 AND AST-2
AST-1
AST-2A
AST-2B
Open Circuit Potential
Scan Rate
Surface Condition:
Critical Pitting Potential
CORRELATIONS BETWEEN DIFFERENT SHORT-TERM TEST RESULTS
RELATING [Clth‾]
(AST-2A) TO CHLORIDE THRESHOLD CONCENTRATIONS IN CONCRETE
CONCRETE SPECIMENS
General
Simulated Deck Slab (SDS) Specimens
General
Black Bar Slabs
Slabs Reinforced With MMFX-II™ Bars
Slabs Reinforced With 3Cr12 Bars
Slabs Reinforced With 2201 Bars
Slabs Reinforced With 316 Solid and Clad (Stelax) Stainless Bars
Chloride Concentration
Three Bar Columns
Square Three Bar Column Specimens
Three Bar Tombstone Columns
Macro-Cell Slab (MS) Specimens
Field Columns
Correlation of Concrete Specimen Data With Results From Accelerated Testing
5. CONCLUSIONS
APPENDIX A
EXAMPLE PH CALCULATION
APPENDIX B
EXAMPLE CALCULATION OF CORROSION RATE FROM POLARIZATION RESISTANCE
APPENDIX C
EXAMPLE CALCULATION OF CORROSION RATE FROM WEIGHT LOSS DATA
BIBLIOGRAPHY
LIST OF FIGURES
Figure 1.1. Photo. Cracked and spalled marine bridge piling
Figure 1.2. Schematic illustration. Various steps in deterioration of reinforced concrete due to chloride induced corrosion
Figure 3.1. Photo. Straight, as-received, MMFX-II™ bar with epoxy-mounted ends and electrical lead
Figure 3.2. Photo. Three bent, as-received Type 2201 stainless steel bars with electrical leads
Figure 3.3. Photo. Abraded MMFX-II™ specimen
Figure 3.4. Photo. Damaged MMFX-II™ specimen
Figure 3.5. Photo. AST-1 wet-dry exposure setup.
Figure 3.6. Photo. AST-1 specimens under test in the upper hold tank (figure 3.5)
Figure 3.7. Schematic illustration. AST-2A experimentation
Figure 3.8. Photo. AST-2A test system
Figure 3.9. Photo. Test chamber with specimens
Figure 3.10. Illustration and photo. Schematic illustration (a) and photograph (b) of the as-received, circumferential AST-2B test specimen
Figure 3.11. Photo. Polished circumferential specimen
Figure 3.12. Schematic illustration. Polished cross section surface specimen
Figure 3.13. Photo. Two polished cross section specimens
Figure 3.14. Photo. Test cell for potentiodynamic polarization measurements
Figure 3.15. Schematic illustration. Standard simulated deck slab specimens
Figure 3.16. Schematic illustration. CREV type simulated deck slab specimens
Figure 3.17. Graphic. Standard specimen nomenclature
Figure 3.18. Graphic. Nonstandard specimen nomenclature
Figure 3.19. Photo. Ponded deck slab specimen under test
Figure 3.20. Photo. Perspective view of exposure site and specimens
Figure 3.21. Schematic illustration. Square three bar column specimen for each of the three bar configurations
Figure 3.22. Schematic illustration. Tombstone type three bar column specimen for each of the three bar configurations
Figure 3.23. Photo. Three bar column specimens under exposure
Figure 3.24. Schematic illustration. Geometry of the macro-cell slab type specimen with both bent and straight bars
Figure 3.25. Photo. Macro-cell slab specimens under exposure
Figure 3.26. Schematic illustration. Geometry of the field column type specimen
Figure 3.27. Photo. Field column specimens under exposure at the Intracoastal Waterway site in Crescent Beach, FL
Figure 4.1. Graph. Change in pH and [Cl-] as a function of time for AST-1 and AST-2 experiments
Figure 4.2. Graph. Plot of polarization resistance versus exposure time for representative alloys during different AST-1 runs (numbers in parentheses)
Figure 4.3. Graph. Plot of polarization resistance versus exposure time for intermediate performing alloys and black bars during different AST-1 (number in parentheses after each alloy designation indicates different AST-1 runs
Figure 4.4. Graph. Plot of polarization resistance versus exposure time for 2201 stainless steel AST-1 specimens with different surface preparation conditions
Figure 4.5. Graph. Plot of polarization resistance versus exposure time for clad stainless steel AST-1 specimens
Figure 4.6. Graph. Plot of polarization resistance versus exposure time for clad stainless steel AST-1 specimens in the intact, abraded (A), and damaged (D) conditions
Figure 4.7. Graph. Plot of polarization resistance for straight versus bent solid bars
Figure 4.8. Graph. Plot of polarization resistance for straight versus bent clad bars
FFigure 4.9. Graph. Comparison of corrosion rate measured by weight loss and calculated from polarization resistance for different solid bars
Figure 4.10. Photo. Type 316 SS specimens subsequent to AST-1 testing
Figure 4.11. Photo. Type 2205 SS specimens subsequent to AST-1 testing
Figure 4.12. Photo. Type 2201 SS specimens subsequent to AST-1 testing
Figure 4.13. Photo. MMFX-II™ specimens subsequent to AST-1 testing
Figure 4.14. Photo. MMFX-II™ abraded specimens subsequent to AST-1 testing
Figure 4.15. Photo. MMFX-II™ damaged specimens subsequent to AST-1 testing
Figure 4.16. Photo. Black bar specimens subsequent to AST-1 testing
Figure 4.17. Graph. Plot of current density versus [Cl‾] such that [Clth‾ ] for alloys with intermediate corrosion resistance is revealed (specimens with B in the designation were bent)
Figure 4.18. Graph. Plot of current density versus [Cl‾] such that [Clth‾ ] for alloys with relatively high corrosion resistance is revealed
Figure 4.19. Graph. Expanded scale plot of current density versus [Cl‾] for alloys with relatively high corrosion resistance is revealed
Figure 4.20. Graph. Plot of current density versus exposure time for 10 specimens each of black bar and 3Cr12. Incremental Cl‾ additions are also shown
Figure 4.21. Graph. Expanded scale view of the current density versus exposure time data from figure 4.20
Figure 4.22. Graph. Plot of current density versus time for a series of 10 MMFX and 2201 specimens polarized to +100 mVSCE. Incremental Cl‾ additions are also shown
Figure 4.23. Graph. Plot of current density versus time for replicate MMFX-II™ specimens
Figure 4.24. Graph. Distribution of [Clth‾ ] for four alloys based upon the 10 µA/cm² current density criterion
Figure 4.25. Graph. Anodic CPP scans for as-received MMFX-II™ specimens in saturated Ca(OH)2 without Cl‾ at scan rates of 0.33, 1.00, and 5.00 mV/s. Arrows indicate direction of forward and reverse scans
Figure 4.26. Graph. Anodic CPP scans on as-received MMFX-II™ specimens with three surface conditions in saturated Ca(OH)2 without Cl‾ at 1.00 mV/s. Arrows indicate direction of forward and reverse scans
Figure 4.27. Graph. Critical pitting potential as a function of [Cl‾] for four bar types
Figure 4.28. Graph. Plot of polarization resistance (AST-1) versus PREN for the test reinforcements
Figure 4.29. Graph. Plot of polarization resistance (AST-1) versus [Clth‾ ] (AST-2A)
Figure 4.30. Graph. Plot of [Clth‾ ] (AST-2A) versus PREN
Figure 4.31. Graph. Plot of [Clth‾ ] (AST-2A) versus the corresponding threshold projected from literature data for pastes, mortars, and concrete
Figure 4.32. Graph. Plot of potential versus exposure time for STD1 and STD2 concrete specimens with black bar reinforcement
Figure 4.33. Graph. Plot of macro-cell current density versus exposure time for STD1 and STD2 concrete specimens with black bar reinforcement
Figure 4.34. Graph. Plot of potential versus exposure time for black bar STD1 concrete specimens with and without a simulated crack
Figure 4.35. Graph. Plot of macro-cell current density versus exposure time for black bar STD1 concrete specimens with and without a simulated crack
Figure 4.36. Graph. Plot of potential versus macro-cell current density for black bar reinforced concrete specimens
Figure 4.37. Photo. Exposed surface of specimen number 3-CCON-BB-2 after 377 days
Figure 4.38. Photo. Traces of the upper three rebars and heavy corrosion products (specimen number 3-CCON-BB-1)
Figure 4.39. Photo. Trace of the upper rebars and heavy corrosion products on specimen number 1-STD1-BB-3
Figure 4.40. Graph. Plot of potential versus exposure time for STD1 concrete specimens with MMFX-II™ reinforcement in comparison to black bar results
Figure 4.41. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with MMFX-II™ reinforcement in comparison to black bar results
Figure 4.42. Graph. Plot of potential versus exposure time for STD1 and STD2 concrete specimens with MMFX-II™ reinforcement
Figure 4.43. Graph. Plot of macro-cell current density versus exposure time for STD1 and STD2 concrete specimens with MMFX-II™ reinforcement
Figure 4.44. Graph. Plot of potential versus exposure time for STD1 concrete specimens with black bar bottom mat and top mat MMFX-II™ reinforcement compared to ones with all MMFX-II™ bars
Figure 4.45. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with black bar bottom mat and top mat MMFX-II™ reinforcement compared to ones with all MMFX-II™ bars
Figure 4.46. Graph. Plot of potential versus exposure time for STD1 concrete specimens with as-received and wire brushed (WB) MMFX-II™ reinforcement
Figure 4.47. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with as-received and wire brushed (WB) MMFX-II™ reinforcement
Figure 4.48. Graph. Plot of potential versus exposure time for STD1 concrete specimens with top mat crevice bars (splice) and MMFX-II™ reinforcement compared to ones with normal bar placement
Figure 4.49. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with top mat crevice bars (splice) and MMFX-II™ reinforcement
Figure 4.50. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated concrete crack and MMFX-II™ reinforcement compared to normal (uncracked) specimens
Figure 4.51. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated concrete crack and MMFX-II™ reinforcement compared to normal (uncracked) specimens
Figure 4.52. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated concrete crack and MMFX-II™ reinforcement compared to ones with a simulated crack and top bar crevice (splice)
Figure 4.53. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated concrete crack and MMFX-II™ reinforcement compared to ones with a simulated crack and top bar crevice (splice)
Figure 4.54. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated concrete crack and MMFX-II™ reinforcement compared to ones with a simulated crack and black bottom bars
Figure 4.55. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated concrete crack and MMFX-II™ reinforcement compared to ones with a simulated crack and black bar bottom mat
Figure 4.56. Graph. Plot of potential versus macro-cell current density for MMFX-II™ reinforced specimens
Figure 4.57. Photo. Top surface of specimen 2-BCAT-MMFX-3 after 461 days of exposure
Figure 4.58. Photo. Trace of the upper rebars and corrosion products on specimen number 1-STD1-MMFX-2
Figure 4.59. Photo. Trace of the upper rebars and corrosion products on specimen number 1-STD2-MMFX-2
Figure 4.60. Photo. Trace of the upper rebars and corrosion products on specimen number 2-WB-MMFX-1
Figure 4.61. Photo. Trace of the upper rebars and corrosion products on specimen number 3-CREV-MMFX-1
Figure 4.62. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CCON-MMFX-1
Figure 4.63. Photo. Trace of the upper rebars and corrosion products on specimen number 2-BCAT-MMFX-1
Figure 4.64. Photo. Trace of the upper rebars and corrosion products on specimen number 2-CCNB-MMFX-1
Figure 4.65. Photo. Trace of the upper rebars and corrosion products on specimen number 3-CCRV-MMFX-1
Figure 4.66. Graph. Plot of potential versus exposure time for STD1 concrete specimens with 3Cr12 reinforcement compared to that for black bar
Figure 4.67. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with 3Cr12 reinforcement compared to that for black bar
Figure 4.68. Graph. Plot of potential versus exposure time for STD1 and STD2 concrete specimens with 3Cr12 reinforcement
Figure 4.69. Graph. Plot of macro-cell current density versus exposure time for STD1 and STD2 concrete specimens with 3Cr12 reinforcement.
Figure 4.70. Graph. Plot of potential versus exposure time for STD1 concrete specimens with wire brushed compared to as-received 3Cr12 bars
Figure 4.71. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with wire brushed compared to as-received 3Cr12 bars
Figure 4.72. Graph. Plot of potential versus exposure time for STD1 concrete specimens with top mat bar crevice (splice) and 3Cr12 reinforcement compared to ones with normal bar placement
Figure 4.73. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with top mat bar crevice (splice) and 3Cr12 reinforcement compared to ones with normal bar placement
Figure 4.74. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated concrete crack and 3Cr12 reinforcement compared to uncracked ones
Figure 4.75. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated concrete crack and 3Cr12 reinforcement compared to uncracked ones
Figure 4.76. Graph. Plot of potential versus exposure time for STD1 concrete specimens with black bar bottom mat and top mat 3Cr12 reinforcement compared to ones with all 3Cr12 bars
Figure 4.77. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with black bar bottom mat and top mat 3Cr12 reinforcement compared to ones with all 3Cr12 bars
Figure 4.78. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated concrete crack and 3Cr12 reinforcement compared to cracked ones with a simulated crack and top bar crevice (splice)
Figure 4.79. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated concrete crack and 3Cr12 reinforcement compared to cracked ones with a simulated crack and top bar crevice (splice)
Figure 4.80. Graph. Plot of potential versus macro-cell current density for 3Cr12 reinforced specimens
Figure 4.81. Photo. Trace of the upper rebars and corrosion products on specimen number 1-STD1-3Cr12-1
Figure 4.82. Photo. Trace of the upper rebars and corrosion products on specimen number 1-STD2-3Cr12-1
Figure 4.83. Photo. Trace of the upper rebars and corrosion products on specimen number 1-WB-3Cr12-1
Figure 4.84. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CREV-3Cr12-1
Figure 4.85. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CCON-3Cr12-1
Figure 4.86. Photo. Trace of the upper rebars and corrosion products on specimen number 1-BCAT-3Cr12-1
Figure 4.87. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CCRV-3Cr12-1.
Figure 4.88. Graph. Plot of potential versus exposure time for STD1 concrete specimens with 2201 reinforcement compared to data for black bar
Figure 4.89. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with 2201 reinforcement compared to data for black bar
Figure 4.90. Graph. Plot of potential versus exposure time for STD1 and STD2 concrete specimens with 2201 reinforcement
Figure 4.91. Graph. Plot of macro-cell current density versus exposure time for STD1 and STD2 concrete specimens with 2201 reinforcement
Figure 4.92. Graph. Plot of potential versus exposure time for STD1 concrete specimens with wire brushed (WB) 2201 bars compared to ones with as-received 2201 bars
Figure 4.93. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with wire brushed (WB) 2201 bars compared to ones with as-received 2201 bars
Figure 4.94. Graph. Plot of potential versus exposure time for STD1 concrete specimens with top mat crevice bars (splice) and 2201 reinforcement compared to ones with normal bar placement
Figure 4.95. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with top mat crevice bars (splice) and 2201 reinforcement compared to ones with normal bar placement
Figure 4.96. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated crack and 2201 reinforcement compared to uncracked ones
Figure 4.97. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated crack and 2201 reinforcement compared to uncracked ones
Figure 4.98. Graph. Plot of potential versus exposure time for STD1 concrete specimens with top mat 2201 bars and bottom mat black bar compared to ones with all 2201 bars
Figure 4.99. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with top mat 2201 bars and bottom mat black bar compared to ones with all 2201 bars
Figure 4.100. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated concrete crack and 2201 reinforcement compared to ones with a simulated crack and black bottom bars
Figure 4.101. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated concrete crack and 2201 reinforcement compared to ones with a simulated crack and black bottom bars
Figure 4.102. Graph. Plot of potential versus exposure time for STD1 concrete specimens with a simulated crack and crevice at top bars (splice) and 2201 reinforcement compared results for ones with cracked concrete and normal top bar placement
Figure 4.103. Graph. Plot of macro-cell current density versus exposure time for STD1 concrete specimens with a simulated crack and crevice at top bars (splice) and 2201 reinforcement compared results for ones with cracked concrete and normal top bar placement
Figure 4.104. Graph. Plot of potential versus macro-cell current density for 2201 reinforced specimens
Figure 4.105. Photo. Trace of the upper rebars and corrosion products on specimen number 1-STD1-2201-3
Figure 4.106. Photo. Trace of the upper rebars and corrosion products on specimen number 1-STD1-2202-2
Figure 4.107. Photo. Trace of the upper rebars and corrosion products on specimen number 1-WB-2201-1
Figure 4.108. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CREV-2201-1
Figure 4.109. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CCON-2201-1
Figure 4.110. Photo. Trace of the upper rebars and corrosion products on specimen number 1-BCAT-2201-1
Figure 4.111. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CCNB-2201-1
Figure 4.112. Photo. Trace of the upper rebars and corrosion products on specimen number 1-CCRV-2201-1
Figure 4.113. Graph. Plot of average potential versus average macro-cell current density at each measurement time for three specimens of the four indicated
Figure 4.114. Graph. Plot of potential versus exposure time for STD1 and STD2 concrete specimens with 316.18, 316.17, and Stelax reinforcement compared to that for black bar in STD1 concrete
Figure 4.115. Graph. Plot of macro-cell current density versus exposure time for STD1 and STD2 concrete specimens with 316.18 reinforcement compared to ones with black bar in STD1 concrete
Figure 4.116. Graph. Plot of chloride concentration at 2.54 cm below the exposed surface of STD1 concrete slabs versus exposure time
Figure 4.117. Graph. Time-to-corrosion results for square 3-bar column specimens
Figure 4.118. Graph. Example potential and current data for macro-cell slab specimens
Figure 4.119. Graph. Time-to-corrosion results for the macro-cell slab specimens without a simulated crack
Figure 4.120. Graph. Time-to-corrosion results for the macro-cell slab specimens with a simulated crack
Figure 4.121. Graph. Plot of time-to-corrosion of reinforced concrete specimens as a function of [Clth‾] as determined from accelerated testing
Figure 4.122. Photo. Example of corner cracking on a 2201 reinforced simulated deck slab specimen
Figure 4.123. Graph. Chloride profile from each of two cores taken from STD1 concrete slabs after 136 days of exposure
LIST OF TABLES
Table 3.1. Listing of reinforcing steel types
Table 3.2. Chemical composition of the rebar types
Table 3.3. Listing of AST-1 runs and the rebar and specimen type for each (“x” indicates that the indicated alloy was tested during that run, and “2” indicates two sets of triplicate specimens)
Table 3.4. Listing of each AST-2A run according to rebar type and number of specimens
Table 3.5. Listing of the number of AST-2B tests for each specimen type and surface condition
Table 3.6. Concrete mix designs
Table 3.7. Listing of the various specimen types, variables, and nomenclature for each
Table 3.8. Listing of specimens reinforced with 316.18 and 3Cr12
Table 3.9. Listing of specimens with 2201 rebar (specimens in shaded cells not yet fabricated)
Table 3.10. Listing of specimens reinforced with MMFX-II™
Table 3.11. Listing of specimens reinforced with Stelax (specimens in shaded cells not yet fabricated)
Table 3.12. Listing of specimens reinforced with SMI (specimens in shaded cells not yet fabricated)
Table 3.13. Listing of specimens reinforced with black bar
Table 4.1. Average polarization resistance for each alloy during each 28-day period of six individual AST-1 runs
Table 4.2. Polarization resistance for each alloy averaged over the six individual AST-1 runs
Table 4.3. Corrosion rate calculated from weight loss of individual specimens of each alloy at the end of the indicated NaCl exposure for the indicated run
Table 4.4. Average corrosion rate calculated from weight loss for each alloy during four individual AST-1 runs
Table 4.5. Listing of projected CT values for the corresponding [Clth‾ ] from AST-2A
Table 4.6. Calculated times-to-corrosion for concrete specimens
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