i
FINAL ANALYSIS OF REINFORCED CONCRETE SPECIMENS
AFTER TEN YEARS OF MARINE EXPOSURE
Riza M. R. Gatdula
and
Ian N. Robertson
Research Report UHM/CEE/12-08
December 2012
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Acknowledgements
This report was prepared by Riza Marie Gatdula under the supervision of Dr. Ian
Robertson of the Department of Civil and Environmental Engineering at the University of
Hawaii at Manoa.
The authors acknowledge Drs. Lin Shen and H. Ronald Riggs review of this
report and their provision of valuable suggestions. Special thanks are also extended to
the Holmes Hall structures laboratory staff and undergraduate laboratory assistants,
Donna Gonzales and Doug Noyes, for their assistance.
The authors are grateful for the considerable contributions made by the State of
Hawaii Department of Transportation (HDOT) for providing the funding for this research
project, and to Ameron Hawaii and Hawaiian Cement for donating aggregate and
concrete mixture constituents.
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ABSTRACT
Twenty-five reinforced concrete field panels, constructed using Hawaiian
aggregates with corrosion inhibiting admixtures and pozzolans intended to reduce
chloride penetration rates through the concrete, were placed at pier 38 in Honolulu
Harbor on the island of O’ahu in 2002 and 2003. The panels were tested for half-cell
potential at various intervals during 10 years of tidal year exposure. Results were
compared with actual corrosion on the reinforcing bars observed after specimen
demolition to provide conclusions and recommendations on the performance of the
concrete constituents and admixtures added into the concrete field panels.
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.
In general, the concrete panels with concrete mixtures having lower water-cement
ratios performed better than those made with higher ratios as concluded from the control
panels. The calcium nitrite type admixtures, DCI and Rheocrete CNI, provided better
corrosion resistance with a higher dosage of 4 gal/yd3 compared to the mixtures with 2
gal/yd3. The replacement of 15% cement with the fly ash performed the best and gave
the most consistent results. The panels with the remaining admixtures exhibited
inconsistent results. Comparisons between half-cell potentials and visual inspection on
the field damage are summarized in Table A - 1.
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Table A - 1: Results of half-cell and visual inspection of field corrosion specimens (Robertson, 2012)
10 L/m3 2 gal/yd3
50% >90% Panel Reinforcing
Months Months Damage Months Inspection
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
1 0.4 Kapaa None Control 40 40 Crack 84 N/A
7 0.35 Kapaa None Control 24 62 Rust 115 Mod ‐ Severe
2 0.4 Halawa None Control 40 40 Cracks and Rust 84 Mod ‐ Severe
3 0.4 Kapaa DCI 10l/m3‐ ‐ None ‐ N/A
4 0.4 Halawa DCI 10l/m340 40 Crack and rust 84 Mod ‐ Severe
3A 0.4 Kapaa DCI 20l/m3111 111 Rust 105 Minor ‐ Mod
5 0.4 Kapaa CNI 10l/m324 24 None ‐ Mod ‐ Severe
6 0.4 Kapaa CNI 10l/m324 46 Rust 80 Minor ‐ Mod
5A 0.4 Kapaa CNI 20l/m358 ‐ None ‐ Minor
15 0.4 Kapaa Rheocrete 5l/m362 62 Crack and rust 84 Minor ‐ Mod
16 0.4 Kapaa Rheocrete 5l/m324 24 None ‐ N/A
17 0.4 Halawa Rheocrete 5l/m324 40 Rust 84 Mod ‐ Severe
17A 0.4 Halawa Rheocrete 5l/m358 ‐ Rust 104 Minor
20 0.4 Kapaa FerroGard 15l/m337 60 Crack and rust 80 Mod ‐ Severe
18 0.4 Halawa FerroGard 15l/m340 62 Crack and rust 84 Mod ‐ Severe
19 0.4 Halawa FerroGard 15l/m349 62 Rust 84 Mod ‐ Severe
21 0.4 Kapaa Xypex 2% 20 37 Crack and rust 84 Mod ‐ Severe
14 0.4 Kapaa Latex Mod. 5% 30 38 Crack and rust 74 Mod ‐ Severe
22 0.4 Kapaa Kryton Kim 2% 24 ‐ Crack 104 Minor
8 0.36 Kapaa Silica Fume 5% 20 ‐ Rust 110 Minor
9 0.36 Kapaa Silica Fume 5% 13 52 Crack and rust 74 Minor ‐ Mod
10 0.36 Kapaa Silica Fume 5% 64 116 None ‐ Minor ‐ Mod
11 0.36 Kapaa Fly Ash 15% 20 80 None ‐ None
12 0.36 Halawa Fly Ash 15% 84 ‐ None ‐ Minor
13 0.36 Halawa Fly Ash 15% 121 ‐ None ‐ 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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TABLE OF CONTENTS
1. INTRODUCTION ................................................................................................................................ 1
1.1 Introduction ................................................................................................................................ 1
1.2 Objective....................................................................................................................................... 3
1.3 Scope .............................................................................................................................................. 3
2. BACKGROUND AND LITERATURE REVIEW ......................................................................... 5
2.1 Introduction ................................................................................................................................ 5
2.2 Mechanisms of Concrete Corrosion.................................................................................. 5
2.3 Concrete Properties Affecting Corrosion ....................................................................... 7
2.3.1 Concrete Permeability ................................................................................................... 7
2.3.2 Alkalinity ............................................................................................................................. 8
2.3.3 Chloride Concentrations .............................................................................................. 9
The Role of Chloride Ions on Corrosion ............................................................................. 9
Mechanism of Chloride Ion Transport ............................................................................ 10
Marine Exposures ..................................................................................................................... 11
2.3.4 Corrosion‐inhibiting Admixtures .......................................................................... 13
2.4 Testing ........................................................................................................................................ 14
2.4.1 Chloride Concentration Tests ................................................................................. 14
2.4.2 Half‐Cell Potential Tests ............................................................................................ 15
2.4.3 Visual Observations ..................................................................................................... 17
2.5 Summary ................................................................................................................................... 18
3. EXPERIMENTAL PROCEDURES .............................................................................................. 19
3.1 Introduction ............................................................................................................................. 19
3.2 Aggregates ................................................................................................................................ 19
3.3 Corrosion‐Inhibiting Admixtures ................................................................................... 19
3.4 Concrete Mix Designs .......................................................................................................... 20
3.5 Concrete Field Panel Fabrication ................................................................................... 22
3.6 Testing Procedures for Non‐Destructive Tests ........................................................ 27
3.6.1 Chloride Concentration Tests ................................................................................. 27
3.6.2 Half‐Cell Potential Tests ............................................................................................ 28
3.6.3 Visual Observation and Reinforcing Steel Actual Corrosion ..................... 30
3.7 Summary ................................................................................................................................... 31
4. RESULTS OF FIELD PANELS AND LIFE‐365 PREDICTIONS ....................................... 33
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4.1 Introduction ............................................................................................................................. 33
4.2 Half‐cell Potentials ................................................................................................................ 33
4.2.1 Half‐cell Results for Control Panels ...................................................................... 34
4.2.2 Half‐cell Results for DCI/CNI Panels .................................................................... 37
4.2.3 Half‐cell Results for Silica Fume Panels .............................................................. 39
4.2.4 Half‐cell Results for Fly Ash Panels ...................................................................... 42
4.3 Visual Observation of External Surfaces and Reinforcing Bars ........................ 43
4.3.1 Visual Observation of Control Panels .................................................................. 45
4.3.2 Visual Observation for DCI/CNI Panels .............................................................. 56
4.3.3 Visual Observation for Silica Fume Panels ........................................................ 65
4.3.4 Visual Observation of Fly Ash Panels .................................................................. 70
4.4 Non‐destructive Tests Compared with Observed Corrosion ............................. 73
4.4.1 Comparisons for Control Panels ............................................................................ 73
4.4.2 Comparisons for DCI/CNI Panels .......................................................................... 74
4.4.3 Comparisons for Silica Fume Panels .................................................................... 75
4.4.4 Comparisons for Fly Ash Panels ............................................................................ 76
4.4.5 Comparisons for Rheocrete 222+ Panels ........................................................... 77
4.4.6 Comparisons for Ferrogard Panels ....................................................................... 78
4.4.7 Comparisons for Other Panels ................................................................................ 79
4.5 Summary ................................................................................................................................... 80
5. CONCLUSIONS ................................................................................................................................ 83
APPENDIX A – References .................................................................................................................. 85
APPENDIX B – Field Panel half‐cell readings and visual observations ........................... 85
APPENDIX C – Final Panel Photos ................................................................................................ 115
APPENDIX D – Reinforcing Bar Photos ………………………….……………..…………………. 143
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LIST OF TABLES
Table 2‐1: Primary Chloride Transport Mechanism for Various Exposures (Cement Concrete & Aggregates Australia 2009) ........................................................................................ 13 Table 2‐2: Maximum Chloride Ion Content in Concrete (Taken from ACI 318‐08, ACI 222R‐01, ACI 201.2R‐01) ..................................................................................................................... 14 Table 2‐3: Corrosion condition related with half-cell potential (HCP) measurements .... 16 Table 3‐1: Admixtures used in this Project and their Mechanics ....................................... 20 Table 3‐2: Concrete mixtures............................................................................................................. 21 Table 4‐1: Corrosion Ranges for Half‐cell Potential Test Results (V vs. CSE) ............... 34 Table 4‐2: Results of half‐cell and visual inspection of field corrosion specimens (Robertson 2012) .................................................................................................................................... 81
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LIST OF FIGURES
Figure 2‐1: Electrochemical process of corrosion (Portland Cement Association 2012). .............................................................................................................................................................. 6 Figure 2‐2: Basic configuration of Half‐Cell Test Electrical Circuit (ASTM Standard C876‐91 1999) ......................................................................................................................................... 16 Figure 3‐1: Test panel dimensions .................................................................................................. 23 Figure 3‐2: Panel reinforcement layout ........................................................................................ 24 Figure 3‐3: Reinforcing Steel Hanging from Formwork ......................................................... 25 Figure 3‐4: Location of Field Panels at Pier 38 Honolulu Harbor ...................................... 26 Figure 3‐5: Placement of Field Panels at Pier 38 (Uno et al. 2004) ................................... 26 Figure 3‐6: Chloride Sample Depths by Core Method ............................................................. 28 Figure 3‐7: Electrical Connection to Reinforcing Steel for Half‐cell Tests ..................... 29 Figure 3‐8: Half‐cell Test Locations ................................................................................................ 30 Figure 4‐1: Half‐cell Potential for Control Panel 2 ................................................................... 35 Figure 4‐2: 3D Representation of Half‐Cell Potential for Control Panel 2 at 9.7 years ......................................................................................................................................................................... 35 Figure 4‐3: Half‐cell Potential for Control Panel 7 ................................................................... 36 Figure 4‐4: 3D Representation of Half‐Cell Potential for Control Panel 7 at 9.6 years ......................................................................................................................................................................... 36 Figure 4‐5: Half‐Cell Potential for DCI Panel 4 ........................................................................... 38 Figure 4‐6: 3D Representation of Half‐Cell Potential for DCI Panel 4 at 9.7 years ..... 38 Figure 4‐7: Half‐cell Potential for Rheocrete CNI Panel 5A .................................................. 40 Figure 4‐8: 3D Representation of Half‐Cell Potential for CNI Panel 5A at 8.7 years .. 40 Figure 4‐9: Half‐cell Potential for 5% Silica Fume Panel 10................................................. 41 Figure 4‐10: 3D Representation of Half‐Cell Potential for SF Panel 10 at 9.2 years .. 41 Figure 4‐11: Half‐cell Potential for 15% Fly Ash Panel 11 .................................................... 42 Figure 4‐12: 3D Representation of Half‐Cell Potential for FA Panel 11 at 9.3 years . 43 Figure 4‐13: Exterior Panel Photo Sample ................................................................................... 44 Figure 4‐14: Sample Panel Reinforcing Bar Corrosion Location and Length Diagram Sample .......................................................................................................................................................... 44 Figure 4‐15: Panel 2 Halawa Control with 0.40 w/c ‐ All Surfaces at 9.7 years .......... 45 Figure 4‐16: Panel 2 ‐ Right Surface at 9.7 years ‐ Rust Magnified ................................... 46 Figure 4‐17: Panel 2 ‐ Front Surface at 9.7 years ‐ Rust and Cracks Magnified ........... 47 Figure 4‐18: Panel 2 – Front Surface at 7.0 years – Rust Magnified ................................. 47 Figure 4‐19: Panel 2 Reinforcing Steel Top and Bottom Layers ......................................... 48 Figure 4‐20: Panel 2 Corrosion Location and Lengths ........................................................... 49 Figure 4‐21: Panel 2 Top Layer Top Surface – Corrosion on Reinforcing Steel ........... 49 Figure 4‐22: Panel 2 Top Layer Bottom Surface ‐ Corrosion on Reinforcing Steel .... 50 Figure 4‐23: Panel 2 Bottom Layer Bottom Surface ‐ Corrosion on Reinforcing Steel ......................................................................................................................................................................... 50 Figure 4‐24: Panel 2 Bottom Layer Top Surface ‐ Corrosion on Reinforcing Steel .... 51 Figure 4‐25: Panel 7 Kapaa Control 0.35 w/c ‐ All Surfaces at 9.6 years........................ 52 Figure 4‐26: Panel 7 ‐ Front Surface at 9.6 years ‐ Rusts Magnified ................................. 52 Figure 4‐27: Panel 7 – Front Surface at 7.0 years – No Rust or Cracks Observed ...... 53
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Figure 4‐28: Panel 7 Top and Bottom Layer Reinforcing Steel ........................................... 53 Figure 4‐29: Panel 7 Corrosion Location and Lengths ........................................................... 54 Figure 4‐30: Panel 7 Top Layer Top Surface – Corrosion on Reinforcing Steel ........... 55 Figure 4‐31: Panel 7 Top Layer Bottom Surface – Corrosion on Reinforcing Steel ... 55 Figure 4‐32: Panel 7 Bottom Layer Top and Bottom Surfaces – Corrosion on Reinforcing Steel ..................................................................................................................................... 56 Figure 4‐33: Panel 4 Halawa 0.40 w/c with 2 gal/cy DCI ‐ All Surfaces at 9.7 year... 57 Figure 4‐34: Panel 4 ‐ Front Surface at 9.7 years ‐ Rust and Cracks Magnified ........... 57 Figure 4‐35: Panel 4 – Front Surface at 7.0 years – Rust Magnified ................................. 58 Figure 4‐36:Panel 4 – Left Surface at 9.7 years – Rust and Cracks Magnified .............. 58 Figure 4‐37: Panel 4 – Rear Surface at 9.7 years – Rust and Cracks Magnified ........... 59 Figure 4‐38: Panel 4 Reinforcing Steel Top and Bottom Layers ......................................... 59 Figure 4‐39: Panel 4 Corrosion Location and Lengths ........................................................... 60 Figure 4‐40: Panel 2 Top Layer Top Surface – Corrosion on Reinforcing Steel ........... 61 Figure 4‐41: Panel 4 Top Layer Bottom Surface – Corrosion on Reinforcing Steel ... 61 Figure 4‐42: Panel 4 Bottom Layer Bottom Surface – Corrosion on Reinforcing Steel ......................................................................................................................................................................... 62 Figure 4‐43: Panel 4 Bottom Layer Top Surface – Corrosion on Reinforcing Steel ... 62 Figure 4‐44: Panel 5A Kapaa 0.40 w/c with 4 gal/cy CNI ‐ All Surfaces at 9.7 years 63 Figure 4‐45: Panel 5A Reinforcing Steel Top and Bottom Layers ...................................... 64 Figure 4‐46: Panel 5A Corrosion Location and Lengths ........................................................ 64 Figure 4‐47: Panel 5A Top Layer Top and Bottom Surface ‐ Corrosion on Reinforcing Steel ............................................................................................................................................................... 65 Figure 4‐48: Panel 10 – Front Surface at 6.7 years – No Rust or Cracks Observed .... 66 Figure 4‐49: Panel 10 Reinforcing Steel Top and Bottom Layers ...................................... 67 Figure 4‐50: Panel 10 Corrosion Location and Lengths ......................................................... 67 Figure 4‐51: Panel 10 Top Layer Top Surface ‐ Corrosion on Reinforcing Steel ......... 68 Figure 4‐52: Panel 10 Top Layer Bottom Surface ‐ Corrosion on Reinforcing Steel . 68 Figure 4‐53: Panel 10 Bottom Layer Bottom Surface ‐ Corrosion on Reinforcing Steel ......................................................................................................................................................................... 69 Figure 4‐54: Panel 10 Bottom Layer Top Surface ‐ Corrosion on Reinforcing Steel.. 69 Figure 4‐55: Panel 11 Kapaa 0.36 w/c with 15% Fly Ash – All Surfaces at 9.3 years 70 Figure 4‐56: Panel 11 – Front Surface at 6.7 years – No Rust or Cracks Observed .... 71 Figure 4‐57: Panel 11 Reinforcing Steel Top and Bottom Layers ...................................... 71 Figure 4‐58: Panel 11 Corrosion Location and Lengths ......................................................... 72 Figure 4‐59: Panel 11 Top Layer Top and Bottom Surfaces – Corrosion on Reinforcing Steel ..................................................................................................................................... 72
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1. INTRODUCTION
1.1 Introduction
Reinforced concrete is a widely used building construction material because of its
economic value, suitability for architectural and structural functions, fire resistance,
rigidity, low maintenance, and material availability (Wight & MacGregor, 2009).
However, due to concrete’s low tensile strength, it is susceptible to cracking when
subjected to tensile stresses. These cracks allow moisture and harmful contaminants to
seep through the concrete to the reinforcing steel, causing it to deteriorate. This
deterioration of metal, also known as corrosion, increases the volume of the reinforcing
steel by several times. The increase in volume then causes more cracking, delamination,
and spalling of concrete adjacent to the bars.
The rate of corrosion of the steel reinforcement in concrete can be
controlled or inhibited using a number of different methods. These include the use of
good construction design procedures like increasing the concrete strength, decreasing
concrete permeability by lowering the water-to-cementitious material ratio, requiring a
minimum cover to reinforcing bars, and restricting the chlorides in the mix. In addition,
the use of protective coatings such as epoxy coatings, corrosion resistant alloys (such as
stainless steel), corrosion-inhibiting admixtures, engineered plastics and polymers, and
cathodic and anodic protection are also used. The use of corrosion-inhibiting admixtures
is considered one of the more cost effective solutions to the corrosion process (NACE
International, 2002) being the focus of this research.
This research project consists of three Phases. Phase I, a study conducted by Bola
and Newtson (2000), evaluated the effectiveness of corrosion-inhibiting admixtures
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added at the time of pier construction at eight sites on Oahu. On-site pH, permeability,
half-cell potential, linear polarization, resistance and resistivity tests were performed.
Core samples were taken to measure the mechanical properties and chloride contents at
various depths from the surfaces of each test specimen.
Phase II was performed by Pham and Newtson (2001), Okunaga, Robertson and
Newtson (2005), and Kakuda, Robertson and Newtson (2005). These studies evaluated
the concrete properties of mixtures that included corrosion-inhibiting admixtures and
pozzolanic materials. Okunaga et al. (2005) studied concrete specimens made in the
University of Hawaii at Manoa Holmes Hall structures laboratory. These specimens with
added corrosion-inhibiting admixtures were introduced to an accelerated cyclic wetting
and drying pattern. Representing the marine environment by a salt-water solution, half-
cell potential, linear polarization, and resistivity were measured after each cycle. The
effects of corrosion-inhibiting admixtures were determined through chloride
concentration, pH, and air permeability tests performed upon corrosion failure.
Phase III, by Uno, Robertson and Newtson (2004) and Cheng and Robertson
(2006) monitored twenty-five reinforced concrete field panels constructed and placed in
the tidal zone at Honolulu Harbor’s Pier 38. Each of the field panels included one of the
corrosion-inhibiting admixtures used in Phase II of this study. In the field, half-cell
potential and air permeability tests were performed and core samples were taken and used
to measure chloride content and pH at various depths from the surface. Ropert and
Robertson (2012) compared some of the specimen results with Life-365 corrosion
prediction software and suggested recommendations to improve the prediction software
correlations.
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The scope of the research reported here includes the final inspection of the field
panels after ten-year monitoring at Pier 38.
1.2 Objective
The objective of this research is to determine the effectiveness of corrosion-
inhibiting admixtures and pozzolanic materials used in reinforced concrete panels with
exposure to marine environment. The concrete admixtures used for the various phases of
this research project include DAREX Corrosion Inhibitor (DCI), Rheocrete CNI,
Rheocrete 222+, FerroGard 901, Xypex Admix C-2000, latex modifiers, silica fume, fly
ash, and Kryton KIM. Final investigation of the reinforced concrete panels includes
chloride concentration tests at various depths, half-cell potential readings, and visual
inspection of the exterior of each panel and visual inspection of the reinforcing steel after
the concrete had been removed.
1.3 Scope
This report will outline the updated results of half-cell readings taken in 2012 and
breaking of the concrete panels to detect corrosion of the reinforcing steel. These
observations will be compared to half-cell reading results obtained during the ten years of
field exposure. The 2008 chloride concentration data has been prepared and tested but
will not be included in this report. The 2009, 2010, and 2012 cores and samples had been
prepared but were not tested for chloride concentration, and therefore, will not be
included in this report.
Chapter 2 gives a brief overview of the corrosion mechanism, chloride concentration,
and half-cell reading tests that were used in evaluating the corrosion in the reinforced
concrete panels. Chapter 0 references the different aggregates, corrosion-inhibiting
4
admixtures, concrete mix designs, field panel fabrication, and testing procedures for this
study. Chapter 4 presents the results for half-cell potentials and comparisons between
non-destructive tests and actual corrosion on the reinforcing steel. Chapter 5 presents
conclusions and recommendations from this study.
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2. BACKGROUND AND LITERATURE REVIEW
2.1 Introduction
Corrosion is a massive deterioration problem that happens everywhere. It has
been an increasing problem over the past 150 years because of the danger it poses to our
systems and the hazard it presents to public safety. It affects not only our infrastructures,
but also our pipelines, water and sewer systems, and oil and gas exploration and
production (Schmitt, 2009). The cost of corrosion in the United States alone is about $2.2
trillion per year while repair and maintenance of corroded buildings, bridges, piers, and
roads cost the government billions of dollars each year (NACE International, 2002).
The focus of this chapter will be on the basic theory and mechanisms of
corrosion, chloride concentration test, and half-cell readings used to determine and
estimate the corrosion of the reinforced concrete panels placed in the tidal zone in a
marine water environment. In addition, a brief overview of the effects of corrosion-
inhibiting admixtures that were used with concrete mixes designed to lessen or delay the
corrosion process will be presented.
2.2 Mechanisms of Concrete Corrosion
Corrosion is a natural phenomenon that involves deterioration of material and its
properties due to environmental electrochemical reaction. For corrosion to occur, four
components for an electrochemical reaction must be present: anode that undergoes
oxidation-reduction reaction, cathode that consumes electrons, electrical conductive path
as a useful electric current, and an electrolyte to transfer ions. In the case for reinforced
concrete, the concrete, an aqueous environment around the reinforcing steel, serves as the
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electrolyte to complete the electrochemical cell circuit (World Corrosion Organization,
2012).
Figure 2-1 illustrates the complete electrochemical process for corrosion of iron in
reinforcing steel.
Figure 2-1: Electrochemical process of corrosion(Portland Cement Association, 2012).
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: (Eqn. 2.1)
The electrons that are released at the anode flow through the reinforcing steel to
the areas where the iron is exposed to oxygen and water (Brady & 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.
eFeFe 22
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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, the
resulting combination gives Fe(OH)3 (known as hydrated oxide), which is the red-brown
material commonly called rust (McMurry & Fay, 2001; Roberge, 2006; Slater, 1983).
Briefly then, for corrosion to occur there must be a formation of ions and release
of electrons at an anodic surface where oxidation or deterioration of the metal occurs.
There must be a simultaneous reaction at the cathodic surface to consume the electrons
generated at the anode. These electrons can serve to neutralize positive ions such as the
hydrogen ions (H+), or create negative ions. The anodic and cathodic reactions must go
on at the same time and at equivalent rates. However, what is usually recognized as the
corrosion process occurs only at the areas that serve as anodes (Roberge, 2006).
2.3 Concrete Properties Affecting Corrosion
2.3.1 Concrete Permeability
Although concrete is a hard, dense material, it does contain pores that are
interconnected throughout the material. These pores provide some permeability in the
concrete (Slater, 1983). Permeability of concrete is very important to the corrosion
8
process. For chloride to act as a catalyst for corrosion, both chloride ions and oxygen
must be present at the steel. The permeability of concrete determines the rate at which
aggressive species penetrate the concrete to reach the steel. For a given concrete cover,
chloride ions will penetrate the concrete relatively quickly at areas of high permeability
(Lewis & Copenhagen, 1959).
High water-cement ratios generally lead to either a greater number of pores, or
larger pores, both of which lead to a relatively permeable concrete (Stratfull, 1957). Some
other factors that influence the permeability of concrete are the type, size and gradation
of the aggregates, consolidation methods, curing conditions and temperature (Kitowski &
Wheat, 1997).
2.3.2 Alkalinity
Concrete provides a naturally high-alkaline environment (pH typically between
12 and 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 rate 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 passive layer around the
reinforcing steel is depassivated (or diminished) increasing the susceptibility to corrosion.
The breakdown of the passive layer around the reinforcing steel must take place
prior to activating the corrosion initiation process (ACI Committee 222, 2001).
According to Roberge (2006), the initiation of corrosion occurs at chloride thresholds
9
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 report that the
general minimum corrosion chloride threshold is 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 (Smith & Virmani, 2001).
2.3.3 Chloride Concentrations
The Role of Chloride Ions on Corrosion
Chloride ions are considered to be the primary cause of premature corrosion in
reinforcing steel (Portland Cement Association, 2012). 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 comes from the environments to which the concrete is exposed
including areas that use deicing salts or marine environments (Sagues, 2001) if oxygen
and moisture are present to sustain the reaction (Portland Cement Association,
2012)http://www.cement.org/tech/cct_dur_corrosion.asp.
The nature of the interaction between chloride ions and the corrosion of steel in
concrete was not fully understood (Pakshir & Esmaili, 1998) but the most popular theory
is that chloride ions penetrate concrete faster than other ions do (Portland Cement
Association, 2012) The resulting effects include deterioation of steel bar cross section,
induced tensile 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
10
occupy may increase three to six times due to the corrosion process (Smith & Virmani,
2001).
Mechanism of Chloride Ion Transport
The first step in the corrosion process is the penetration of chlorides through the
concrete surface (ACI Committee 222, 2001). Chloride ions can penetrate the concrete by
means of absorption, hydrostatic pressure, and diffusion (Stanish, Hooton, & Thomas,
2001).
Diffusion involves the movement of chloride ions under a concentration gradient.
The concrete must have a continuous liquid phase and there must be a chloride ion
concentration gradient for this to occur (Stanish, Hooton, & Thomas, 2001). Chloride
diffusion rates are affected by numerous factors of which water-to-cement ratios,
concrete composition, humidity, temperature, and pH are some. Another diffusion rate
factor in concrete structures is when structures are subjected to water saturated
environments such as marine environments (Smith & Virmani, 2001).
A second mechanism for chloride ingress is permeation, driven by pressure
gradients. Permeation may occur if there is an applied hydraulic head on one face of the
concrete and chlorides are present. A situation where a hydraulic head is maintained on a
highway structure is rare, however (Stanish, Hooton, & Thomas, 2001).
A more common transport method is absorption. As a concrete surface is exposed
to the environment, it will undergo wetting and drying cycles. When water (possibly
containing chlorides) encounters a dry surface, it will be drawn into the pore structure
though capillary suction. Absorption is driven by moisture gradients. Typically, the
depth of drying is small, however, and this transport mechanism will not, by itself, bring
11
chlorides to the level of the reinforcing steel unless the concrete is of extremely poor
quality and the reinforcing steel is shallow. It does serve to quickly bring chlorides to
some depth in the concrete and reduce the distance that they must diffuse to reach the
reinforcing steel (Stanish, Hooton, & Thomas, 2001). The alternating wetting and drying
pattern that occurs on concrete structures (such as at the tidal zones of piers) is reported
to accelerate the corrosion process (Smith & Virmani, 2001).
Marine Exposures
Marine structures are exposed to chlorides from seawater in four exposure
conditions: submerged zone, tidal zone, splash and spray, and coastal zone (Cement
Concrete & Aggregates Australia, 2009).
Submerged structures are subject to sustained direct contact with seawater.
Chlorides penetrate into concrete mainly by ion diffusion, and to some extent permeation
of the salt solutions. The concrete surface zones may form protective coatings with a low
permeability due to ion exchange reactions with other compounds of seawater, resulting
in films of Mg(OH)2 and CaCO3. Therefore, the penetration rate of chlorides into these
structures is often considerably lower than estimated from laboratory experiments, where
no protective films can be formed due to the test method chosen (Cement Concrete &
Aggregates Australia, 2009).
Structures in tidal or splash and spray zone are subject to cyclic exposure to
seawater. Ingress of chlorides into the concrete is supported by capillary absorption of the
seawater upon direct contact. Capillary absorption gains importance as the degree of
drying between the individual wetting periods increases. The splash and spray zone is
12
sometime referred to as the atmospheric zone (Cement Concrete & Aggregates Australia,
2009).
Coastal structures may be subject to considerable chloride concentration in the
atmosphere, which may be deposited or washed out with rain on the surface of structures.
Ingress of chlorides into the concrete is supported by capillary absorption of the water
upon direct contact, and chloride removal during wash out is possible through reverse
diffusion. With long drying periods, carbonation of the concrete surface may lead to the
release of the bound chlorides in the carbonated zone (Cement Concrete & Aggregates
Australia, 2009).
There are exposure conditions where concrete is in contact with seawater under
significant hydrostatic pressure. In cases where the opposite face of a concrete element is
subject to drying condition such as immersed transport tunnel or basements, Wick action
needs to be considered (Cement Concrete & Aggregates Australia, 2009).
Table 2-1 summarizes the primary chloride transport mechanisms applicable to
structures in various exposure conditions.
13
Table 2-1: Primary Chloride Transport Mechanism for Various Exposures (Cement Concrete & Aggregates Australia, 2009)
2.3.4 Corrosion-inhibiting Admixtures
Corrosion- inhibiting admixtures may be classified as either organic, inorganic or
both. An ideal corrosion inhibitor is a chemical compound that when added in sufficient
amounts to concrete, can prevent corrosion of reinforcing steel without decreasing
concrete strength (Hope & Ip, 1989).
According to Berke and Hicks (1994), there are several inhibitors that have been
tested by many researchers, but only one (calcium nitrite) has been used commercially on
a wide scale in the United States, Japan, and Europe. In general, calcium nitrite improves
the properties of hardened concrete. Many other inhibitors have resulted in a decrease in
compressive strength of concrete (Loto, 1992). Even though corrosion inhibitors have
been widely used over the years, there is considerable debate about their long-term
benefits and abilities to prolong the service lives of structures.
14
2.4 Testing
2.4.1 Chloride Concentration Tests
There are three different commonly used analytical methods 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 liquid (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 2-2 lists the various maximum water-
soluble and acid-soluble chloride ion content values in concrete reported by the ACI
Committee 318 (2008), ACI Committee 222 (2001), and ACI Committee 201 (2001).
Table 2-2: Maximum Chloride Ion Content in Concrete (ACI)
Acid-solubleACI 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
0.1 0.15 0.1 0.08
Reinforced concrete in dry conditions
0.2 0.3 0.15 0.15
Category
Chloride limit for new construction (% by mass of cement)Test method
Water-soluble
15
Currently, ACI Committee 222 (2001) and ACI Committee 201 (2001)
recommend a common maximum chloride threshold value of 0.15% water-soluble or
0.20% acid-soluble chloride ion content, measured by mass of cement. 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 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 2-2 are noted to differ from those values
reported by the ACI Committee 318. 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.
2.4.2 Half-Cell Potential Tests
The tendency of any metal to react with an environment is indicated by the
potential it develops in contact with the environment. In reinforced concrete structures,
concrete acts, as an electrolyte and the reinforcement will develop a potential depending
on the concrete environment (Song & Saraswathy, 2007). The schematic diagram for
open circuit potential measurements is as shown in Figure 2-2.
16
Figure 2-2: Basic configuration of Half-Cell Test Electrical Circuit (ASTM Standard C876-91, 1999)
The principle involved in this technique is essentially measurement of corrosion
potential of rebar with respect to a standard reference electrode, such as saturated calomel
electrode (SCE), copper/copper sulfate electrode (CSE), silver/ silver chloride electrode
etc. As per ASTM Standard C876-91 (1999), the probability of reinforcement corrosion
is as follows in Table 2-3.
Table 2-3: Corrosion condition related with half-cell potential (HCP) measurements
17
Although there are several methods for the diagnosis, detection and measurement
of corrosion in reinforcing steel, there is no consensus regarding which method assesses
corrosion levels in reinforced concrete structures most accurately (Song & Saraswathy,
2007). Therefore, half-cell potential tests must not be relied as the only criterion to
determine corrosion probability (Song & Saraswathy, 2007). For more information on the
standard test for half-cell potentials, refer to ASTM Standard C876-91 (1999).
2.4.3 Visual Observations
Approximately 80 percent of all non-destructive inspection procedures are
accomplished by the direct visual methods. Visual inspection is the oldest and most
common form of non-destructive evaluation used to inspect for corrosion. It provides a
means of detecting and examining a wide variety of component and material surface
discontinuities, such as cracks, corrosion, contamination, surface finish, concrete quality,
spalled concrete cover, and exposed reinforcement, which are important because of their
relationship to structural failures (Song & Saraswathy, 2007; Visual Inspection, 1998;
NACE International, 2010).
Visual inspection is frequently used to provide verification when defects are
found initially using other non-destructive inspection techniques. Its reliability depends
upon the ability and experience of the inspector who must know how to search for critical
flaws and how to recognize areas where failure could occur. This inspection procedure
may be greatly enhanced by the use of appropriate combinations of magnifying
instruments, borescopes, light sources, video scanners, and other devices. In some cases,
sonic inspection is carried out along with hammers in order to assess the soundness of
18
concrete (Song & Saraswathy, 2007; Visual Inspection, 1998; NACE International,
2010).
The main disadvantage of visual inspection is that the surface to be inspected
must be relatively clean and accessible to either the naked eye or to an optical aid. Other
disadvantages include subjective representation of observed flaws, imprecise
measurements, and labor intensive (NACE International, 2010).
2.5 Summary
This chapter presented a literature review of information on the mechanisms of
corrosion, the properties of concrete affecting corrosion, the influences of chlorides on
corrosion, 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 on the non-
destructive tests used for the project was presented.
19
3. EXPERIMENTAL PROCEDURES
3.1 Introduction
This chapter will give a brief description of the materials used for all the concrete
mixtures, concrete mixes previously used for Phase II and Phase III of this project, and
experimental procedures for measuring the chloride concentration tests, half-cell
readings, and visual observations of the reinforcing steel used in the concrete panels for
Phase III of this project. 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 Aggregates
The aggregates used for the concrete mixtures for this project were obtained from
Kapaa Quarry, operated by Ameron Hawaii, and Halawa Quarry, operated by Hawaiian
Cement. Both of the quarries are located on the island of O’ahu. Pham and Newtson
(2001) provide a more detailed description of the aggregates used on this research.
3.3 Corrosion-Inhibiting Admixtures
The corrosion-inhibiting admixtures used for this research project include:
DAREX Corrosion Inhibitor (DCI), Rheocrete CNI, Rheocrete 222+, FerroGard 901,
Xypex Admix C-2000, latex modifier, silica fume, fly ash, and Kryton KIM.
For simplicity, the admixtures will be referred to here as Type 1 or Type 2 based
on their approach to reducing corrosion. Their functions are described in Table 3-1. More
20
detailed information about all admixtures used in this report is provided by Uno and
Robertson (2004).
Table 3-1: Admixtures used in this Project and their Mechanics
From Table 3-1, Type 1 admixtures include Xypex, fly ash, silica fume, latex
modifier and Kryton KIM. Type 2 admixtures include CNI, DCI, and FerroGard.
Rheocrete 222+ has both Type 1 and 2 functions.
Concretes using type 1 admixtures are expected to have reduced air permeability.
Concretes using Type 2 admixtures are expected to have a higher chloride concentration
threshold value (Cheng & Robertson, 2006).
3.4 Concrete Mix Designs
The concrete mix designs used in both Phase II and Phase III of this project are
presented in Table 3-2. A thorough explanation of the mix designs including the design
21
slump, aggregate proportions, water-cement ratio, and air content is presented in the
report by Ropert and Robertson (2012).
Table 3-2: Concrete mixtures
Mixture Label Panel 1 Panel 2 Panel 7 Panel 3 Panel 3A Panel 4 Panel 5 Panel 5A Panel 6 Panel 15 Panel 16 Panel 17 Panel 17A
(Based on Phase II Label) (C2) (HC2) (C1) (D4) (D5) (D4) (CNI4) (CNI5) (CNI4) (RHE2) (RHE2) (HRHE2) (HRHE2)
Aggregate Source Kapaa Halawa Kapaa Kapaa Kapaa Halawa Kapaa Kapaa Kapaa Kapaa Kapaa Halawa Halawa
w/c or w/(c+fa) or w/(c+sf) 0.4 0.4 0.35 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4
Cement to Concrete Ratio (%) 18.96 18.32 20.08 18.98 18.98 18.98 18.98 18.97 18.97 18.94 18.94 18.29 18.29
Paste Volume (%) 31.2 31.2 31.2 31.2 31.2 31.2 31.2 31.2 31.2 31.2 31.2 31.2 31.2
Design Slump (in) 4 4 4 4 4 4 4 4 4 4 4 4 4
(mm) 100 100 100 100 100 100 100 100 100 100 100 100 100
Coarse Aggregate (lb/yd3) 1,576 1,642 1,576 1,576 1,642 1,576 1,576 1,576 1,642 1,576 1,576 1,642 1,642
(kg/m3) 935 974.1 935 935 974.1 935 935 935 974.1 935 935 974.1 974.1
Dune Sand (lb/yd3) 431 573 431 431.5 431.5 431.5 431.5 431.5 572.7 431.5 431.5 572.7 572.7
(kg/m3) 255.7 340 255.7 256 256 256 256 256 339.8 256 256 339.8 339.8
Concrete Sand (lb/yd3) 826.5 759.2 825.7 826.5 826.5 826.5 826.5 826.5 759.2 826.5 826.5 759.2 759.2
(kg/m3) 490.4 450.4 489.9 490.4 490.4 490.4 490.4 490.4 450.4 490.4 490.4 450.4 450.4
Cement (lb/yd3) 733.3 733.3 786.2 733.3 733.3 733.3 733.3 733.3 733.3 733.3 733.3 733.3 733.3
(kg/m3) 435.1 435.1 466.5 435.1 435.1 435.1 435.1 435.1 435.1 435.1 435.1 435.1 435.1
Water (lb/yd3) 292.1 292.1 275.1 275.4 258.7 275.4 275.4 258.7 275.4 292.1 292.1 292.1 292.1
(kg/m3) 173.3 173.3 163.2 163.4 153.5 163.4 163.4 153.5 163.4 173.3 173.3 173.3 173.3
Admixture
(gal/yd3) or (lb/yd3) - - - 2 4 2 2 4 2 1 1 1 1
(l/m3) - - - -9.9 -19.8 -9.9 -9.9 -19.8 -9.9 -4.95 -4.95 -4.95 -4.95
Daratard (oz./sk) 3 3 3 3 3 3 3 3 3 3 3 3 3
(ml/sk) 88.7 88.7 88.7 88.7 88.7 88.7 88.7 88.7 88.7 88.7 88.7 88.7 88.7
Darex (oz./sk) 2 2 2 2 2 2 2 2 2 2 2 2 2
(ml/sk) 59.1 59.1 59.1 59.1 59.1 59.1 59.1 59.1 59.1 59.1 59.1 59.1 59.1
Design Air Content (%) 4 4 4 4 4 4 4 4 4 4 4 4 4
None Liquid DCI Liquid CNI Rheocrete 222+
22
Table 3-2: Concrete mixtures (Cont)
3.5 Concrete Field Panel Fabrication
A total of twenty-five field panel specimens were fabricated in the Phase III study
by Uno et al. (2004). Each panel was 6” thick with a length of 59.5” and width of 21”
(1511 x 533 x 152 mm). Each panel had two layers of No.4 (13 mm) reinforcing steel,
with four longitudinal bars and seven transverse bars in each layer. PVC conduit spacers
were used to separate the two layers of reinforcing bar, ensuring physical and electrical
separation between the layers. A concrete clear cover of exactly 1.5 inches (38 mm) was
Mixture Label Panel 18 Panel 19 Panel 20 Panel 21 Panel 14 Panel 11 Panel 12 Panel 13 Panels 8 Panel 9 Panel 10 Panel 22
(Based on Phase II Label) (none) (none) (FER2) (XYP2) (L5) (FA4) (HFA4) (HFA4) (SF2) (SF2) (SF2) (none)
Aggregate Source Halawa Halawa Kapaa Kapaa Kapaa Kapaa Halawa Halawa Kapaa Kapaa Kapaa Kapaa
w/c or w/(c+fa) or w/(c+sf) 0.4 0.4 0.4 0.4 0.4 0.36 0.36 0.36 0.36 0.36 0.36 0.4
Cement to Concrete Ratio (%) 18.29 18.29 18.95 18.75 19.28 17.24 16.73 16.73 19.4 19.42 19.42 19
Paste Volume (%) 31.2 31.2 31.2 31.2 31.2 33 33 33 32.9 32.9 32.9 31.2
Design Slump (in) 4 4 4 4 4 8-10 8-10 8-10 8-10 8-10 8-10 4
(mm) 100 100 100 100 100 200-250 200-250 200-250 200-250 200-250 200-250 100
Coarse Aggregate (lb/yd3) 1,642 1,642 1,576 1,576 1,576 1,668 1,737 1,737 1,668 1,668 1,668 1,576
(kg/m3) 974.2 974.2 935 935 935 989.6 1030.6 1030.6 989.6 989.6 989.6 935
Dune Sand (lb/yd3) 759.2 759.2 431 431 399.5 526.5 548.9 548.9 521.1 521.1 521.1 431.5
(kg/m3) 450.4 450.4 255.7 255.7 237 312.4 325.7 325.7 309.2 309.2 309.2 256
Concrete Sand (lb/yd3) 572.7 572.7 826.5 825.6 765.2 698 727.4 727.4 679.3 679.3 679.3 826.5
(kg/m3) 339.8 339.8 490.4 489.8 435 414.1 431.6 431.6 403 403 403 490.3
Cement (lb/yd3) 733.3 733.3 733.3 718.5 733.2 689.3 689.3 689.3 771.1 771.1 771.1 733.3
(kg/m3) 435.1 435.1 435.1 426.3 435 409 409 409 457.5 457.5 457.5 435.1
Water (lb/yd3) 292.1 292.1 292.1 292.1 182.1 291.9 291.9 291.9 291.9 291.9 291.9 278.6
(kg/m3) 173.3 173.3 173.3 173.3 108 173.2 173.2 173.2 173.2 173.2 173.2 165.3
Admixture Xypex Latex LiquidSilica Fume Rheomac SF100
Kryton KIM
(gal/yd3) or (lb/yd3) 3 3 3 14.7 146.6 121.77 121.77 121.77 40 40 40 13.5
(l/m3) -14.85 -14.85 -14.85 -8.72 -87 -72.2 -72.2 -72.2 -23.7 -23.7 -23.7 -6.1
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 4 1 1 1 4 4 4 4
Silica Fume Force 10,000D
FerroGard 901 Fly Ash
23
used for the test surface of the panels, with the remaining sides of the panels having
concrete clear cover of at least 2.0 inches (51 mm). 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).
In order to remove any corrosion product and mill scale from the reinforcing steel
used in the concrete field panels, the reinforcement was soaked in a 10 percent sulfuric
acid solution for 30 minutes to one hour, wired brushed, soaked for an additional 10 to 20
minutes, and scrubbed while rinsing in clean water.
Figure 3-1: Test panel dimensions
24
Figure 3-2: Panel reinforcement layout
An access hole as shown on Figure 3-3 was formed at the top of each panel
allowing a single longitudinal steel reinforcing bar to be exposed to provide a connection
for the half-cell measurements.
25
Figure 3-3: Reinforcing Steel Hanging from Formwork
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 Honolulu Harbor on
the island of Oahu as shown in Figure 3-4. 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. Photos of the placement of the field
panels are shown in Figure 3-5 (Uno, et al. 2004).
Access Hole
26
Figure 3-4: Location of Field Panels at Pier 38 Honolulu Harbor
Figure 3-5: Placement of Field Panels at Pier 38 (Uno et al. 2004)
27
3.6 Testing Procedures for Non-Destructive Tests
The following sections describe the testing procedures performed at various times
during the ten years of field exposure.
3.6.1 Chloride Concentration Tests
The field panels were first placed in the ocean at Pier 38 in Honolulu Harbor
between July 2002 and July 2003. Concrete dust samples were collected around March
2004 by Uno et al. (2004) for chloride concentration tests. Concrete samples from the
field panels were collected again around January 2006 under the research of Cheng and
Robertson (2006). Additional field panel samples were taken between February 2007 and
March 2008 and used along with the Life-365 predictions as reported by Ropert and
Robertson (2012).
Chloride concentrations for the concrete field test specimens were obtained using
the acid-soluble chloride test. Cores were used to collect samples at desired depths using
a 1.5-inch diameter by 3-inch length core driller. Cores were taken from the upper third,
lower third 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 as seen on Figure 3-6. Approximately 3 grams (0.11 ounces) of each sample was
crushed into dust and dissolved in 20 mL (0.67 fluid ounces) of extraction liquid obtained
from James Instruments, Inc. Each sample was shaken and allowed to react with the
extraction liquid for one minute before measurements were taken. The CL-2000 Chloride
Field Test System by James Instruments, Inc. was used to determine the chloride
concentration of each panel, following testing procedures included with the equipment.
Readings were taken as a percentage by mass of concrete for each sample. For
28
description on the testing procedures for the 2004 and 2006 chloride concentration tests,
refer to reports by Uno et al. (2004) and Cheng and Robertson (2006).
Figure 3-6: Chloride Sample Depths by Core Method
3.6.2 Half-Cell Potential Tests
After the panels were placed by Uno et al. (2004) at Pier 38 in Honolulu Harbor
between July 2002 and July 2003, the concrete panels were tested for half-cell potentials
on seven different occasions at approximate panel ages of 2.0, 3.5, 4.0, 4.5, 5.0, 5.5, and
7.0 years. The eighth and final half-cell potential readings included in this report are part
of the final analysis of the reinforced concrete panels after approximately 10 years of
exposure to the ocean.
Half-cell potentials for the concrete field test specimens used on all phases of this
research were obtained using a saturated calomel electrode (SCE) and a voltmeter. A test
access hole was made at the top of each panel as part of the panel fabrication to allow a
single longitudinal reinforcement to be exposed and attached to the half-cell lead
connector. A steel screw with attached electrical wire was drilled into the exposed
longitudinal bar for a positive electrical connection point. The test hole, as shown in
Figure 3-7 was sealed after every reading and prior to replacement into the ocean for
29
continued testing. Unfortunately, these seals were not always effective resulting in
corrosion of the exposed end of the reinforcing bar in some panels.
Figure 3-7: Electrical Connection to Reinforcing Steel for Half-cell Tests
Ten locations on the front face of each field panel were used for testing half-cell
potentials performed by Uno et al. (2004). However, to provide a more accurate average
of results, eight additional test locations were tested starting with research performed by
Cheng and Robertson (2006). Figure 3-8 shows the half-cell test locations used for this
report.
30
Figure 3-8: Half-cell Test Locations
3.6.3 Visual Observation and Reinforcing Steel Actual Corrosion
Each of the twenty-five concrete field panels that were used for this research were
inspected using visual observation of the external surfaces of the panel and the top and
bottom layers of reinforcing steel. External photos at the 10-year age include the front
and rear faces, top and bottom edges, and left and right faces of the field panels.
Additional photos were taken of any cracks or areas indicating potential internal
corrosion. After the non-destructive tests were performed, each panel was carefully
31
broken using a sledgehammer and a Hilti concrete coring drill to recover the reinforcing
steel. The PVC conduit spacers used to separate the two layers of reinforcing bars were
removed and photos taken of the top and bottom surfaces of the top and bottom layers of
reinforcement. Additional photos were taken to document any rust found on the
reinforcing steel.
3.7 Summary
This chapter described the aggregates, admixtures, concrete mixtures and
proportions used to create the field test specimens for the Phase III studies. The
fabrication of the Phase III field panel specimens by Uno et al. (2004) was described as
well as the experimental procedures performed on each specimen including chloride
concentration tests and half-cell potential tests. Procedures for visual observation of the
panel exterior and internal reinforcement were also described.
32
33
4. RESULTS OF FIELD PANELS AND LIFE-365 PREDICTIONS
4.1 Introduction
The twenty-five field panels were exposed to the tidal zone at pier 38 at Honolulu
Harbor for 10 years. All but three of these panels were recovered in March 2012 and
brought to the UH Structures Laboratory for final analysis. The three missing panels had
dropped to the bottom of the harbor due to failure of the stainless steel cables holding the
panels, presumably due to corrosion. These panels, numbered 1, 3, and 16, could not be
retrieved for final analysis.
The twenty-two field panels were tested for half-cell potential for comparison
with the actual corrosion observed on the reinforcing steel recovered from each panel.
In this chapter, half-cell readings taken after recovery of the field panels are
shown in 2D and 3D graphs for clarity. In addition, visual observation of the panels’
exterior surfaces and reinforcing bars are presented for comparison with the non-
destructive tests.
4.2 Half-cell Potentials
This section presents the half-cell potentials from tests performed on each
concrete field panel specimens at various collection dates. Half-cell potentials give a
probabilistic determination of corrosion occurrence of reinforcement within the concrete
specimen. Table 4-1 shows the statistical probabilities of corrosion occurrence in
reinforced concrete based on using a copper sulfate electrode (CSE). Field half-cell
potential tests in this study were performed using a saturated calomel electrode (SCE)
and the results were converted to a copper sulfate electrode (CSE) by subtracting 77 mV.
34
Table 4-1: Corrosion Ranges for Half-cell Potential Test Results (V vs. CSE)
Measured Potential (mV) Statistical risk of corrosion occurring
< ‐273 >90%
Between ‐273 and ‐123 50%
> ‐123 <10%
Half-cell readings taken throughout the ten-year exposure are plotted in 2D while
results measured at the end of the 10-year exposure are shown in 3D. The 3D plots show
where the probabilities of corrosion occurrence are high in the reinforced concrete panel.
The 2D plots represent average values for each row of readings across the panel width.
Note that the half-cell lead connection is attached to the top layer of reinforcing steel,
therefore, the plots only show the probability of corrosion occurrence in the top layer
steel and not for the bottom layer steel.
Only a representative sample of plots is shown in this chapter. Plots for all panels
are included in Appendix B.
4.2.1 Half-cell Results for Control Panels
Final half-cell potentials for control panel 2 with 0.40 water-cement ratio are
presented in Figure 4-1 and Figure 4-2. After 9.7 years of exposure age, the potential
readings from Figure 4-1 indicate that the top half of the panel shows a 50% probability
of corrosion occurrence and probability of over 90% corrosion occurring for the bottom
half of the panel. Visual inspection of the concrete panel’s exterior surface confirmed the
presence of corrosion after 7.0 years of exposure. Figure 4-2 shows the half-cell
potentials of control panel 2 after 9.7 years exposure. The middle and bottom rows show
readings above the 273 limit and therefore have 90% probability of corrosion occurrence
at those locations. This was confirmed by observation of significant corrosion on the
35
reinforcing steel in the lower half of the panel as described later in this chapter.
Figure 4-1: Half-cell Potential for Control Panel 2
Figure 4-2: 3D Representation of Half-Cell Potential for Control Panel 2 at 9.7 years
0
50
100
150
200
250
300
350
400
450
Ave
rag
e H
alf
Cel
l (
-0.
001m
V).
Distance from top of panel (cm)
Panel #2: Halawa Control with 0.40 w/c ratio
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #2: Halawa Control 0.40 w/c
36
Figure 4-3: Half-cell Potential for Control Panel 7
Figure 4-4: 3D Representation of Half-Cell Potential for Control Panel 7 at 9.6 years
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #7: Kapaa Control with 0.35 w/c ratio
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #7: Kapaa Control 0.35 w/c
37
Final half-cell potentials for control panel 7 with 0.35 water-cement ratio are
presented in Figure 4-3 and Figure 4-4. At 7.0 years of exposure, the potential readings
from Figure 4-3 indicate that the top half of the panel shows a 50% probability or
corrosion occurrence and probability of over 90% corrosion occurring for the bottom half
of the panel. There were no indications of rusts or cracks from visual inspection of
external surface. From 7.0 to 9.6 years, the potential readings consistently indicate that
the bottom portion of the panel has 90% probability of corrosion. Figure 4-4 shows the
half-cell potentials of the control panel 7 after 9.6 years exposure. The middle and bottom
rows show readings above the 273 limit and therefore have 90% probability of corrosion
occurrence at these locations. Visual inspection of the concrete panel’s exterior surface
up to 7 years exposure showed no signs of cracking or corrosion, however, at 9.6 years,
the inspection confirmed the presence of rust.
4.2.2 Half-cell Results for DCI/CNI Panels
Final half-cell potentials for panel 4 with 10 L/m3 (2 gal/yd3) of DCI are presented
in Figure 4-5 and Figure 4-6. After only 3.4 years exposure, high half-cell readings were
observed at the bottom of the panel. These high readings persisted until surface
indications of corrosion were observed during the 7.0 year visual inspections. At 9.7
years, the potential readings in Figure 4-5 indicate that the bottom portion of the panel
has greater than 90% probability of corrosion. Figure 4-6 shows the half-cell potentials of
panel 4 after 9.7 years exposure. The highest readings are along the left edge of the panel
at the middle and bottom where readings were well above the 273 limit.
38
Figure 4-5: Half-Cell Potential for DCI Panel 4
Figure 4-6: 3D Representation of Half-Cell Potential for DCI Panel 4 at 9.7 years
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #4: Halawa 0.40 w/c with DCI 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
9.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
5
6
Panel #4: Halawa 0.40 w/c with 2 gal/cuyd DCI
39
Final half-cell potentials for panel 5A with 20 L/m3 (4 gal/yd3) of CNI are
presented in Figure 4-7 and Figure 4-8. At 6.2 years, the potential readings from Figure
4-7 indicate that the panel has 50% probability of corrosion occurrence throughout while
at 8.7 years, potential readings show less than 10% probability of corrosion. The 3D plot
from Figure 4-8 also indicates a small chance of corrosion throughout the panel. Visual
inspection of the concrete panel’s exterior surface showed no indication of cracks or rusts
at the 6.2 and 8.7 ages.
4.2.3 Half-cell Results for Silica Fume Panels
Final half-cell potentials for panel 10 with 5% cement replacement with Silica Fume are
presented in Figure 4-9 and Figure 4-10. After 5.3 years, the potential readings from
Figure 4-9 indicate that the middle and bottom portions of the panel have 50% probability
of corrosion occurrence. At 9.2 years, potential readings show 50% probability of
corrosion at the top and middle portions of the panel and over 90% probability of
corrosion occurrence at the bottom. The 3D plot in Figure 4-10 shows highest corrosion
probability at the bottom right portion of the concrete panel. Visual inspection of the
concrete panel’s exterior surface showed no indication of cracks or rusts at the 6.7 and
9.2 ages. However, on inspecting the reinforcement, significant corrosion was evident on
the right had bar towards the bottom of the panel.
40
Figure 4-7: Half-cell Potential for Rheocrete CNI Panel 5A
Figure 4-8: 3D Representation of Half-Cell Potential for CNI Panel 5A at 8.7 years
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #5A: Kapaa 0.40 w/c with CNI at 20l/m3 (4 gal/cuyd)
0.7 years
2.5 years
3.2 years
3.6 years
4.3 years
4.7 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #5A: Kapaa 0.40 w/c with 4 gal/cuyd CNI
41
Figure 4-9: Half-cell Potential for 5% Silica Fume Panel 10
Figure 4-10: 3D Representation of Half-Cell Potential for SF Panel 10 at 9.2 years
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #10: Kapaa 0.36 w/c with 5% Silica Fume (Grace)
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.2 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #10: Kapaa 0.36 w/c with 5% Silica Fume (Grace)
42
4.2.4 Half-cell Results for Fly Ash Panels
Final half-cell potentials for panel 11with 15% cement replacement with fly Ash
are presented in Figure 4-11 and Figure 4-12. The potential readings from Figure 4-11
indicate that the entire panel had 50% probability of corrosion for the entire time of
exposure. At 9.3 years, potential readings from Figure 4-11 and Figure 4-12 show less
than 10% probability of corrosion throughout the panel. Visual inspection of the concrete
panel’s exterior surface showed no indication of cracks or rust and the interior inspection
of the reinforcement indicated no corrosion.
Figure 4-11: Half-cell Potential for 15% Fly Ash Panel 11
0
50
100
150
200
250
300
350
400
450
Ave
rag
e H
alf
Cel
l (
-0.
001m
V).
Distance from top of panel (cm)
Panel #11: Kapaa 0.36 w/c with 15% Fly Ash
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.3 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
43
Figure 4-12: 3D Representation of Half-Cell Potential for FA Panel 11 at 9.3 years
4.3 Visual Observation of External Surfaces and Reinforcing Bars
This section presents visual observations of the twenty-two concrete field panel
specimens after the end of their multi-year exposure in the tidal zone. Visual observations
include exterior surface photos of each panel and inspection of the top and bottom layer
reinforcing bars after the panels had been broken apart. Exterior panel photos include the
front, back, left, right, top, and bottom faces as shown in Figure 4-13. Each face was
inspected for any cracks and signs of rusts and close-up photos of these areas are
included in this report. Reinforcing bar photos include top and bottom surface photos for
both top and bottom layers of reinforcing steel as shown in Figure 4-14. Each layer was
inspected for corrosion and close-up photos of these areas are included in this report.
Approximate location and length of reinforcing steel corrosion is presented in diagrams
similar to Figure 4-14.
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #11: Kapaa 0.36 w/c with 15% Fly Ash
44
Figure 4-13: Exterior Panel Photo Sample
Figure 4-14: Sample Panel Reinforcing Bar Corrosion Location and Length Diagram Sample
45
Because of the access hole provided to the top end of one of the top reinforcing
bars for half-cell reading electrode connection, corrosion was often observed at this
location. In addition, errors during coring of chloride samples occasionally damaged
areas of reinforcing steel resulting in limited corrosion at these locations. These areas are
indicated by symbols in the reinforcing steel photographs, but were not included in the
corrosion analysis since they were not the result of chloride penetration through the
concrete cover.
Previous photos of the exterior front surface of the concrete field specimens will
be shown for comparison with the recent photos if any new rust and cracks are observed.
Only a representative number of photos at the final collection date are shown in
this chapter. All panel photos are included in Appendix C and D.
4.3.1 Visual Observation of Control Panels
Figure 4-15: Panel 2 Halawa Control with 0.40 w/c - All Surfaces at 9.7 years
46
Final photographs of control panel 2 surfaces are presented in Figure 4-15, Figure
4-16, and Figure 4-17, and while the 7.0-year age exterior photo of control panel 2 is
presented in Figure 4-18. At 9.7 years, Figure 4-16 shows rust and cracks on the bottom
right edge of the concrete panel indicating corrosion n the control panel’s reinforcing
steel. Figure 4-17 shows a new rust location at the top portion of concrete panel
compared to the panel at 7.0 years in Figure 4-18 showing rust at the bottom left and right
portions of the panel.
Figure 4-16: Panel 2 - Right Surface at 9.7 years - Rust Magnified
47
Figure 4-17: Panel 2 - Front Surface at 9.7 years - Rust and Cracks Magnified
Figure 4-18: Panel 2 – Front Surface at 7.0 years – Rust Magnified
48
Overall reinforcing bar photos of concrete panel 2 are presented in Figure 4-19
with locations and lengths of corrosion shown in Figure 4-20. Figure 4-21, Figure 4-22,
Figure 4-23, and Figure 4-24 show magnified photos of the corroded steel for each layer
and surface. Figure 4-19 and Figure 4-20 verify that the reinforcing steel is corroding at
the bottom left and right sides of the concrete panel as indicated by the half-cell readings.
Figure 4-21 and Figure 4-22 show magnified photos of the corrosion at the top layer top
surface reinforcement of control panel 2. The upper portion shows surface corrosion due
to the half-cell lead connection and damage due to the coring. The lower portion shows
significant corrosion on the left and right sides of the reinforcing steel.
Figure 4-19: Panel 2 Reinforcing Steel Top and Bottom Layers
49
Figure 4-20: Panel 2 Corrosion Location and Lengths
Figure 4-21: Panel 2 Top Layer Top Surface – Corrosion on Reinforcing Steel
50
Figure 4-22: Panel 2 Top Layer Bottom Surface - Corrosion on Reinforcing Steel
Figure 4-23: Panel 2 Bottom Layer Bottom Surface - Corrosion on Reinforcing Steel
51
Figure 4-24: Panel 2 Bottom Layer Top Surface - Corrosion on Reinforcing Steel
Corrosion had also occurred on the right hand bar in the bottom layer. Top and
bottom surfaces of the bottom layer are shown in Figure 4-23 and Figure 4-24,
respectively.
Final photographs of control panel 7 surfaces are presented in Figure 4-25 and
Figure 4-26 while the 7.0-year age exterior photo of control panel 7 is presented in Figure
4-27.
At 9.6 years, Figure 4-26, shows a crack and evidence of rust at the bottom left of
the panel. At 7.0 years in Figure 4-27 showed no cracks or rust at the top surface.
Overall reinforcing bar photos of control panel 7 are presented in Figure 4-28
with locations and lengths of corrosion shown in Figure 4-29. Figure 4-30, Figure 4-31,
and Figure 4-32 show magnified photos of the corroded steel for each layer and surface.
52
Figure 4-25: Panel 7 Kapaa Control 0.35 w/c - All Surfaces at 9.6 years
Figure 4-26: Panel 7 - Front Surface at 9.6 years - Rusts Magnified
53
Figure 4-27: Panel 7 – Front Surface at 7.0 years – No Rust or Cracks Observed
Figure 4-28: Panel 7 Top and Bottom Layer Reinforcing Steel
54
The overall photo shows corrosion at lower left and right sides for both surfaces
of both layers of steel.
Figure 4-30 and Figure 4-31 show the top layer top and bottom surfaces for
control panel 7. The upper part shows corrosion due to the lead connection from the half-
cell test. The lower part of the top layer shows pitting corrosion at the left and right sides.
Figure 4-32 shows the bottom layer top and bottom surfaces. Pitting corrosion can
also be seen on the right side of the top surface.
Figure 4-29: Panel 7 Corrosion Location and Lengths
55
Figure 4-30: Panel 7 Top Layer Top Surface – Corrosion on Reinforcing Steel
Figure 4-31: Panel 7 Top Layer Bottom Surface – Corrosion on Reinforcing Steel
56
Figure 4-32: Panel 7 Bottom Layer Top and Bottom Surfaces – Corrosion on Reinforcing Steel
4.3.2 Visual Observation for DCI/CNI Panels
Final surface photographs of panel 4 with 10 L/m3 (2 gal/yd3) of DCI are
presented in Figure 4-33, Figure 4-34, Figure 4-36, and Figure 4-37 while the 7.0-year
age exterior photo of DCI panel 4 is presented in Figure 4-35. At 9.7 years, Figure 4-34,
shows the same crack and rust location at the lower portion of concrete panel as observed
at 7.0 years in Figure 4-35.
Figure 4-36 and Figure 4-37 show rust and cracks on the bottom left edge of the
concrete panel indicating corrosion on the control panel’s reinforcing steel. Additional
areas of cracking and rust were observed on the rear lower right, upper left and right
surfaces of the panel.
57
Figure 4-33: Panel 4 Halawa 0.40 w/c with 2 gal/cy DCI - All Surfaces at 9.7 year
Figure 4-34: Panel 4 - Front Surface at 9.7 years - Rust and Cracks Magnified
58
Figure 4-35: Panel 4 – Front Surface at 7.0 years – Rust Magnified
Figure 4-36:Panel 4 – Left Surface at 9.7 years – Rust and Cracks Magnified
59
Figure 4-37: Panel 4 – Rear Surface at 9.7 years – Rust and Cracks Magnified
Figure 4-38: Panel 4 Reinforcing Steel Top and Bottom Layers
60
Overall reinforcing bar photos of panel 4 are presented in Figure 4-38 with
locations and lengths of corrosion shown in Figure 4-39. Figure 4-40, Figure 4-41, Figure
4-42, and Figure 4-43 show magnified photos of the corroded steel for each layer and
surface.
Figure 4-38 and Figure 4-39 confirm that the reinforcing steel was corroding at
the lower left side of the top layer and at the lower right side of the bottom layer of
reinforcing. Figure 4-40 and Figure 4-41 show magnified photos of the corrosion at the
top layer top and bottom surfaces. The lower portion shows significant loss of steel due to
corrosion on the left side of the reinforcing steel.
Figure 4-39: Panel 4 Corrosion Location and Lengths
61
Figure 4-40: Panel 2 Top Layer Top Surface – Corrosion on Reinforcing Steel
Figure 4-41: Panel 4 Top Layer Bottom Surface – Corrosion on Reinforcing Steel
62
Figure 4-42: Panel 4 Bottom Layer Bottom Surface – Corrosion on Reinforcing Steel
Figure 4-43: Panel 4 Bottom Layer Top Surface – Corrosion on Reinforcing Steel
63
Figure 4-42 and Figure 4-43 show magnified photos of the corrosion on the
bottom layer top and bottom surface of DCI panel 4.
Final surface photographs of panel 5A with 20 L/m3 (4 gal/yd3) of CNI are
presented in Figure 4-44. No rust or cracks were observed on the exterior surfaces of the
panel. Figure 4-45, Figure 4-46, and Figure 4-47 confirm that there is no corrosion on the
top and bottom layer reinforcing bars except for rust on the upper part of the top layer
steel due to the connection for the half-cell lead as seen from magnified photos in Figure
4-47.
Figure 4-44: Panel 5A Kapaa 0.40 w/c with 4 gal/cy CNI - All Surfaces at 9.7 years
64
Figure 4-45: Panel 5A Reinforcing Steel Top and Bottom Layers
Figure 4-46: Panel 5A Corrosion Location and Lengths
65
Figure 4-47: Panel 5A Top Layer Top and Bottom Surface - Corrosion on Reinforcing Steel
4.3.3 Visual Observation for Silica Fume Panels
No final photographs were taken for panel 10 with 5% Silica Fume. Figure 4-48
shows the top surface after 6.7 years exposure, at which time SF panel 10 showed no rust
or cracks on the exterior surfaces.
Overall reinforcing bar photos of SF panel 10 are presented in Figure 4-49 with
locations and lengths of corrosion shown in Figure 4-50. Figure 4-51, Figure 4-52, Figure
4-53, and Figure 4-54 show magnified photos of the corroded steel for each layer and
surface.
Figure 4-49 and Figure 4-50 shows corrosion on the bottom right of the top layer
top surface. Corrosion is also evident on the lower left of the bottom layer top surface.
66
Figure 4-48: Panel 10 – Front Surface at 6.7 years – No Rust or Cracks Observed
Figure 4-51 and Figure 4-52 show magnified photos of the corrosion at the top
layer top and bottom surface reinforcement of SF panel 10. The half-cell lead connection
at the upper portion of the panel caused corrosion at the top and bottom surface of the top
layer. The right side middle to lower portion of the panel shows pitting corrosion on the
reinforcing steel in Figure 4-51 and on the bottom surface in Figure 4-52.
Figure 4-53 and Figure 4-54 show the magnified photos of corrosion on the top
and bottom surfaces of the bottom layer of reinforcing. Surface corrosion was found at
the lower left and right portion of the reinforcing steel for both top and bottom surfaces
67
Figure 4-49: Panel 10 Reinforcing Steel Top and Bottom Layers
Figure 4-50: Panel 10 Corrosion Location and Lengths
68
Figure 4-51: Panel 10 Top Layer Top Surface - Corrosion on Reinforcing Steel
Figure 4-52: Panel 10 Top Layer Bottom Surface - Corrosion on Reinforcing Steel
69
Figure 4-53: Panel 10 Bottom Layer Bottom Surface - Corrosion on Reinforcing Steel
Figure 4-54: Panel 10 Bottom Layer Top Surface - Corrosion on Reinforcing Steel
70
4.3.4 Visual Observation of Fly Ash Panels
Final surface photographs of panel 11 with 15% Fly Ash are presented in Figure
4-55, Error! Reference source not found., and Error! Reference source not found.
while the 6.7-year age exterior photo of FA panel 11 is presented in Figure 4-56. At 9.3
years, the front surface shown in Figure 4-55 shows no crack or rust similar to the panel
at 6.7 years in Figure 4-56.
Overall reinforcing bar photos of FA panel 11 are presented in Figure 4-57 with
locations and lengths of corrosion shown in Figure 4-58. Apart from corrosion at the half-
cell access point and one coring location, there was no evidence of corrosion.
Figure 4-55: Panel 11 Kapaa 0.36 w/c with 15% Fly Ash – All Surfaces at 9.3 years
71
Figure 4-56: Panel 11 – Front Surface at 6.7 years – No Rust or Cracks Observed
Figure 4-57: Panel 11 Reinforcing Steel Top and Bottom Layers
72
Figure 4-58: Panel 11 Corrosion Location and Lengths
Figure 4-59: Panel 11 Top Layer Top and Bottom Surfaces – Corrosion on Reinforcing Steel
73
4.4 Non-destructive Tests Compared with Observed Corrosion
This section presents comparisons for all panels based on the final analysis. Half-
cell readings for all panels are presented in Appendix B, and visual observations in
Appendix C and D. These were analyzed and compared to determine the accuracy of the
half-cell tests and also to determine which admixture types will be recommended for
marine exposed applications. Some panels were lost at the harbor but the tests done on
the panels before they were lost will be referenced in the following sections.
4.4.1 Comparisons for Control Panels
This section presents comparisons for control panels 1, 2, and 7.
Control Panel 1 - Kapaa Control with 0.40 w/c ratio
Seven-year half-cell readings indicate high potential of corrosion on the bottom
part of the concrete panel. A crack on the panel was seen at 7.0-year age. Because the
panel was lost at the harbor, no 2012 2D and 3D half-cell reading plots, external surface
photos, and reinforcing steel photos were obtained. However, based on the cracking
observed after 7 years, it is likely that significant corrosion had occurred at last on the top
layer edge bar below that crack.
Control Panel 2 - Halawa Control with 0.40 w/c ratio
Half-cell potential readings at the 9.7-year indicate high potential of corrosion at
the middle and bottom of the concrete panel. Visual observation of the external surface
shows corrosion at the middle, bottom left and right sides of the panel. The reinforcing
steel inspection confirmed pitting corrosion on the lower part of the top and bottom layer
reinforcing steel. The observations performed on the panel all confirm that the half-cell
readings correctly predicted corrosion.
74
Control Panel 7 - Kapaa Control with 0.35 w/c ratio
The 2012 half-cell readings at the concrete’s 9.6-year age indicate high risk of
corrosion on the middle and bottom parts of the concrete panel. Visual inspection of the
exterior of the surface indicated a crack on the slab edge near the bottom of the panel.
The reinforcing steel showed corrosion at the bottom left and right sides of the top layer
and bottom right of the bottom layer top surface.
4.4.2 Comparisons for DCI/CNI Panels
This section presents comparisons for concrete field panels 3, 3A, 4, 5, 5A, and 6.
DCI Panel 3 - Kapaa 0.40 w/c ratio with DCI at 10 L/m3 (2 gal/cuyd)
DCI panel 3 was lost at the harbor and so no 2012 half-cell potential readings,
external photos, and reinforcing bar photos were obtained. Half-cell potential at 7.0 years
showed less than 10% chance of corrosion in the steel and the external photo at the 7-year
age showed no indication of corrosion or cracks on the surface. The half-cell readings
and visual observation indicate that corrosion had not initiated after 7 years exposure.
DCI Panel 3A - Kapaa 0.40 w/c ratio with DCI at 20 L/m3 (4 gal/cuyd)
Half-cell potential readings indicate more than 90% risk of corrosion at the
bottom right side of the steel. Visual observation of the external surface of the panel
agreed with the half-cell readings, and the reinforcing steel showed pitting corrosion on
the top layer lower right side. The visual observations performed on the panel confirmed
the corrosion indicated by the half-cell readings.
DCI Panel 4 - Halawa 0.40 w/c ratio with DCI at 10 L/m3 (2 gal/cuyd)
Half-cell readings indicated high potential of corrosion at the middle left section
of the panel. External photos showed cracks and rust on the bottom left side and rear
75
faces of the panel. The reinforcing steel inspection confirmed that there was severe
pitting corrosion on the lower left side of the top layer steel and on the lower right side of
the bottom layer steel. The visual observation of the panel’s reinforcement confirmed the
half-cell predictions.
CNI Panel 5 - Kapaa 0.40 w/c ratio with CNI at 10 L/m3 (2 gal/cuyd)
Half-cell readings showed a high potential for corrosion at the middle section of
the panel. External visual observation showed rust formation at the bottom left surface
but the actual reinforcing steel corrosion was seen at the middle left and middle section of
the top and bottom layer steel. The half-cell readings indicated likelihood of corrosion
which was confirmed by the visual observation of the panel’s reinforcement.
CNI Panel 5A - Kapaa 0.40 w/c ratio with CNI at 20 L/m3 (4 gal/cuyd)
Half-cell readings showed very small risk of corrosion and the external photos did
not show any sign of cracks or rust. The reinforcing steel inspection confirmed that the
panel was free of corrosion, confirming that the half-cell potentials and visual
observation were correct.
CNI Panel 6 - Kapaa 0.40 w/c ratio with CNI at 10 L/m3 (2 gal/cuyd)
Half-cell readings showed 50% probability of corrosion and external photos
showed a small sign of rust forming at the bottom right side of the panel. The reinforcing
steel inspection confirmed the corrosion on the middle to lower right of the top layer of
steel. The bottom layer showed no sign of corrosion. Corrosion had occurred when the
half-cell readings indicated 50% probability of corrosion.
4.4.3 Comparisons for Silica Fume Panels
This section presents comparisons for concrete field panels 8, 9, and 10.
76
SF Panel 8 - Kapaa 0.36 w/c ratio with 5% Silica Fume (Master Builders)
The half-cell readings showed 50% chance of corrosion occurrence on the steel.
External photos showed corrosion on the rear surface and the bottom left side of the
panel. The reinforcing steel did indeed show surface corrosion on the bottom left of the
panel. The half-cell readings and visual observation correctly identified the location of
corrosion.
SF Panel 9 - Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)
Half-cell readings indicated 90% risk of corrosion occurrence throughout the
panel with the highest potential readings at the lower right side of the panel. External
surface and reinforcing steel photos show that corrosion had initiated on the lower left
side of the panel top reinforcement.
SF Panel 10 - Kapaa 0.36 w/c ratio with 5% Silica Fume (Grace)
The highest half-cell potential was measured on the middle and bottom right
sections of the concrete panel. No external photos were taken but the reinforcing steel did
show corroded areas on the middle and lower right sections of the panel. The half-cell
readings correctly predicted the corrosion on the steel.
4.4.4 Comparisons for Fly Ash Panels
This section presents comparisons for concrete field panels 11, 12, and 13.
FA Panel 11 - Kapaa 0.36 w/c ratio with 15% Fly Ash
Half-cell potential readings indicated low risk of corrosion on the steel throughout
the panel. External photos show some discoloration on the concrete on the lower left and
right sides of the panel. Reinforcing steel photos show no corrosion on the steel. The
half-cell potential results match the actual reinforcing steel corrosion.
77
FA Panel 12 - Halawa 0.36 w/c ratio with 15% Fly Ash
Half-cell potentials showed less than 10% probability of corrosion on the upper
part of the panel and about 50% probability of corrosion on the lower right side of the
panel. This was confirmed by the reinforcing steel photos which showed actual corrosion
on the lower right side of the top layer steel. The half-cell potential readings agree with
the extent and location of corrosion on the steel.
FA Panel 13 - Halawa 0.36 w/c ratio with 15% Fly Ash
Half-cell potential results indicated less than 10% risk of corrosion on the steel.
External surface photos showed a small discoloration on the bottom right side of the
panel but the reinforcing steel showed no indication of rust. The half-cell potential
readings and external surface photos agree with the reinforcing steel photos indicating the
panel is free from corrosion.
4.4.5 Comparisons for Rheocrete 222+ Panels
This section presents comparisons for concrete field panels 15, 16, 17, and 17A.
Rheocrete Panel 15 - Kapaa 0.40 w/c ratuiwith Rheocrete 222+ at 5 L/m3 (1 gal/cuyd)
Half-cell readings showed 50% risk of corrosion on the steel. External photos
showed corrosion on the lower right side of the panel with minor discoloration on the
bottom left and right sides. Actual corrosion on the reinforcing steel was at the lower
right side of the steel with the bottom layer free from corrosion. The half-cell readings
agree with the actual corrosion on the reinforcing steel.
Rheocrete Panel 16 - Kapaa 0.40 w/c ratio with Rheocrete 222+ at 5 L/m3 (1 gal/cuyd)
No final half-cell readings or external and reinforcing steel photographs were
obtained because panel 16 was lost at the harbor. Half-cell readings at 7.0 years showed
78
50% probability of corrosion occurrence at the steel though no cracks or rust were
observed on the panel’s surface.
Rheocrete Panel 17 - Halawa 0.40 w/c ratio with Rheocrete 222+ at 5 L/m3 (1 gal/cuyd)
Half-cell readings showed 50% probability of corrosion occurrence on the steel.
External photos were not recorded for this panel, but the reinforcing steel photos show
pitting corrosion on the lower left and right sides of the top reinforcing layer and surface
corrosion on the bottom layer steel. The half-cell potential readings agree with the actual
corrosion on the reinforcing steel.
Rheocrete Panel 17A - Halawa 0.40 w/c ratio with Rheocrete 222+ at 5 L/m3 (1 gal/cuyd)
Half-cell potentials showed a 50% risk of corrosion occurrence on the steel the
lower left side of the panel. External photographs show corrosion at the lower left side of
the front surface and left and right side of the panel. Actual corrosion on the steel agrees
with the half-cell readings, and external photos of this panel.
4.4.6 Comparisons for Ferrogard Panels
This section presents comparisons for concrete field panels 18, 19, and 20.
Ferrogard Panel 18 - Kapaa 0.40 w/c ratio with Rheocrete 222+ at 5 L/m3 (1 gal/cuyd)
Half-cell potential readings showed more than 90% risk of corrosion occurrence
mostly at the lower center and right side of the panel. External photos show corrosion on
the lower left and right sides of the front and rear surfaces of the panel. Pitting corrosion
was observed on the reinforcing steel with most of the lower part of the top layer and one
side of the bottom layer being corroded. The half-cell potentials and the external photos
all agree with the actual corrosion on the reinforcement.
79
Ferrogard Panel 19 - Halawa 0.40 w/c ratio with Ferrogard at 15 L/m3 (3 gal/cuyd)
Half-cell readings indicated more than 90% risk of corrosion at the lower left and
right sides of the panel. External photos showed corrosion on the lower left and right
sides of the panel and lower right of the front surface. Actual corrosion on the steel was
found at the mentioned locations for the top layer and at the right side for the bottom
layer. The half-cell readings and the visual observations all agree on the same result.
Ferrogard Panel 20 - Kapaa 0.40 w/c ratio with Ferrogard at 15 L/m3 (3 gal/cuyd)
Half-cell readings showed more than 90% risk of corrosion at the lower left part
of the front surface of the panel. External photos show evidence of rusting on the front
face’s lower left section and a small sign of corrosion at the lower right side of the panel.
Visual observation of the reinforcing steel showed corrosion on the lower left part of the
panel, agreeing with the half-cell readings done for this panel.
4.4.7 Comparisons for Other Panels
This section presents comparisons for concrete field panels 14, 21, and 22.
Latex Modifier Panel 14 - Kapaa 0.40 w/c ratio with 5% Latex Modifier
The half-cell readings indicated more than 90% risk of corrosion mostly at the
lower right part of the front surface. External and reinforcing steel photos agreed and
showed the actual corrosion at the lower right side of the panel. Half-cell readings and
visual observation correctly predicted the corrosion on the reinforcing steel.
Xypex Panel 21 - Kapaa 0.40 w/c ratio with 2% Xypex
Half-cell readings showed more than 90% risk of corrosion at the middle and
bottom parts of the front surface. Visual observation of the external surface and
reinforcing steel of the panel showed corrosion on the lower left side of the front surface
80
of the concrete panel. The half-cell potential readings and visual observation on the
exterior surfaces and actual corrosion on the reinforcing steel all concur.
KIM Panel 22 - Kapaa 0.40 w/c ratio with 2% Kryton KIM
Half-cell readings that showed 50% risk of corrosion at the bottom left side of the
panel’s front face. Visual observation of the external surfaces showed cracking after 8.7
years and reinforcing steel inspection confirmed that there was actual surface corrosion
on the lower left side of the panel. The half-cell readings and external and reinforcing bar
photos all concur.
4.5 Summary
Half-cell potentials at various ages were presented with the distribution of half-
cell potential for the panels. Exterior surface and reinforcing steel photos were shown to
determine the actual corrosion on the panel’s reinforcing steel. The mentioned non-
destructive tests were compared to the actual corrosion of the steel to determine the
accuracy of the tests and also determine the effectiveness of the corrosion-inhibiting
admixtures used in this project.
Comparisons between half-cell potentials and visual inspection on the field
damage is summarized and shown on Table 4-2, taken from Improving Concrete
Durability through the Use of Corrosion Inhibitors by Robertson (2012). Table 4-2 is
updated to include inspection on the actual corrosion of the reinforcing steel.
81
Table 4-2: Results of half-cell and visual inspection of field corrosion specimens (Robertson, 2012)
10 L/m3 2 gal/yd3
50% >90% Panel Reinforcing
Months Months Damage Months Inspection
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
1 0.4 Kapaa None Control 40 40 Crack 84 N/A
7 0.35 Kapaa None Control 24 62 Rust 115 Mod ‐ Severe
2 0.4 Halawa None Control 40 40 Cracks and Rust 84 Mod ‐ Severe
3 0.4 Kapaa DCI 10l/m3‐ ‐ None ‐ N/A
4 0.4 Halawa DCI 10l/m340 40 Crack and rust 84 Mod ‐ Severe
3A 0.4 Kapaa DCI 20l/m3111 111 Rust 105 Minor ‐ Mod
5 0.4 Kapaa CNI 10l/m324 24 None ‐ Mod ‐ Severe
6 0.4 Kapaa CNI 10l/m324 46 Rust 80 Minor ‐ Mod
5A 0.4 Kapaa CNI 20l/m358 ‐ None ‐ Minor
15 0.4 Kapaa Rheocrete 5l/m362 62 Crack and rust 84 Minor ‐ Mod
16 0.4 Kapaa Rheocrete 5l/m324 24 None ‐ N/A
17 0.4 Halawa Rheocrete 5l/m324 40 Rust 84 Mod ‐ Severe
17A 0.4 Halawa Rheocrete 5l/m358 ‐ Rust 104 Minor
20 0.4 Kapaa FerroGard 15l/m337 60 Crack and rust 80 Mod ‐ Severe
18 0.4 Halawa FerroGard 15l/m340 62 Crack and rust 84 Mod ‐ Severe
19 0.4 Halawa FerroGard 15l/m349 62 Rust 84 Mod ‐ Severe
21 0.4 Kapaa Xypex 2% 20 37 Crack and rust 84 Mod ‐ Severe
14 0.4 Kapaa Latex Mod. 5% 30 38 Crack and rust 74 Mod ‐ Severe
22 0.4 Kapaa Kryton Kim 2% 24 ‐ Crack 104 Minor
8 0.36 Kapaa Silica Fume 5% 20 ‐ Rust 110 Minor
9 0.36 Kapaa Silica Fume 5% 13 52 Crack and rust 74 Minor ‐ Mod
10 0.36 Kapaa Silica Fume 5% 64 116 None ‐ Minor ‐ Mod
11 0.36 Kapaa Fly Ash 15% 20 80 None ‐ None
12 0.36 Halawa Fly Ash 15% 84 ‐ None ‐ Minor
13 0.36 Halawa Fly Ash 15% 121 ‐ None ‐ None
Field Panel Details Field Half‐cell Field Panel Damage
Field
Panel
w/c
Ratio
Aggregate
Source
Inhibiting
Admixture
Admixture
Dosage
82
83
5. CONCLUSIONS
Based on the results of the study, the following conclusions were drawn.
The control panel comprised of the Kapaa aggregates with a water-cement ratio of
0.35 exhibited improved corrosion resistance than the control panels with a 0.40
water-cement ratio, as would be expected.
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 fly ash panels gave the most consistent results. Final half-cell readings and
visual observations indicated low probabilities of corrosion initiation and
demonstrated good performance.
The silica fume panels showed inconsistent results.
Half-cell readings were generally a good indicator of the presence of corrosion on
the reinforcing steel.
Visual inspection of the exterior surface of the panels was not reliable for early
detection of corrosion. However, if a crack formed or evidence of rust product
was observed on the panel surface, this was always associated with moderate to
severe corrosion on the reinforcing steel at that location.
84
85
APPENDIX A
REFERENCES
ACI Committee 201. "Guide to Durable Concrete." ACI 201.2R‐01, American Concrete Institute, 2001.
ACI Committee 222. "Protection of Metals in Concrete Against Corrosion." ACI 222R‐
01, American Concrete Institute, 2001. ACI Committee 318. "Building Code Requirements for Structural Concrete." (318‐
08) and Commentary (318R‐08), American Concrete Institute, 2008. "ASTM Standard C876‐91." Standard Test Method for Corrosion Potentials of
Uncoated Reinforcing Steel in Concrete. Vols. DOI: 10.1520/C0033‐03R06. West Conshohocken, PA: www.astm.org, 1999.
Berke, N.S., and M.C. Hicks. "Predicting Chloride Profiles in Concrete." Corrosion Vol.
50, no. 3 (1994): pp 234‐239. Bola, Mereoni M. B., and Craig Newtson. "Field Evaluation of Corrosion in Reinforced
Concrete Structures in Marine Environment." Research Report UHM/CEE/00‐01, Department of Civil and Environmental Engineering, University of Hawaii at Manoa College of Engineering, 2001.
Cement Concrete & Aggregates Australia. "Chloride Resistance of Concrete." Cement
Concrete & Aggregates Australia. 2009. http://www.concrete.net.au/publications/pdf/ChlorideResistance.pdf (accessed 2012).
Cheng, Huiping, and Ian N. Robertson. "Performance of Admixtures Intended to
Resist Corrosion in Concrete Exposed to a Marine Environment." Research Report UHM/CEE/06‐08, Department of Civil and Environmental Engineering, University of Hawaii at Manoa College of Engineering, 2006.
George F. Hays, PE. "Now is the Time." World Corrosion Organization.
http://www.corrosion.org/images_index/nowisthetime.pdf (accessed 2012). Hope, Brian B., and Alan K.C. Ip. "Corrosion Inhibitors for Use in Concrete." ACI
Materials Journal Vol. 86, no. 6 (1989): pp 602‐608. Kakuda, Donn, Ian N. Robertson, and Craig Newtson. "Evaluation of Non‐destructive
Techniques for Corrosion Detection in Concrete Exposed to a Marine Environment." Research Report UHM/CEE/05‐04, Department of Civil and
86
Environmental Engineering, University of Hawaii at Manoa College of Engineering, 2005.
Kitowski, C.J., and H.G. Wheat. "Effect of Chlorides on Reinforcing Steel Exposed to
Simulated Concrete Solutions, Corrosion." Corrosion Vol. 53, no. 3 (1997): pp 216‐226.
Lewis, D.A, and W.J. Copenhagen. "Corrosion of Reinforcing Steel in Concrete in
Marine Atmospheres." Corrosion Vol. 15, no. 7 (1959): pp 60‐66. Life‐365. Life365 Software Overview. 2012. http://www.life‐365.org/overview.html
(accessed 2012). Loto, C.A. "Effect of Inhibitors and Admixed Chloride on Electrochemical Corrosion
Behavior of Mild Steel Reinforcement in Concrete in Seawater." Corrosion Vol. 48, no. 9 (1992): pp 759‐763.
McMurry, J., and R.C. Fay. Chemistry. Third Edition. Upper Saddle River, NJ: Prentice‐
Hall, Inc., 2001. NACE International. "Cost of Corrosion and Preventive Strategies in the United
States." NACE International The Corrosion Society. 2002. http://events.nace.org/publicaffairs/cost_corr_pres/cost_corrosion_files/frame.htm (accessed 2012).
Office of Research, Development, and Technology, Office of Infrastructure, RDT.
"FHWA‐RD‐98‐088 Corrosion Protection ‐ Concrete Bridges." U.S. Department of Transportation Federal Highway Administration. 1998. http://www.fhwa.dot.gov/publications/research/infrastructure/structures/98088/results.cfm#4corrosion (accessed 2012).
Okunaga, Grant, Ian N. Robertson, and Craig Newtson. "Laboratory Study of
Concrete Produced with Admixtures Intended to Inhibit Corrosion." Research Report UHM/CEE/05‐05, Department of Civil and Environmental Engineering, University of Hawaii at Manoa College of Engineering, 2005.
Pakshir, M., and S. Esmaili. "Scientia Iranica | Articles | The Effect of Chloride Ion
Concentration on the Corrosion of Concrete." Vers. Vol. 4, No. 4, pp 201‐205. Scientia Iranica. Sharif University of Technology, January 1998. 1998. http://www.scientiairanica.com/pdf/articles/00001012/si040409.pdf (accessed 2012).
Pham, Phong, Ian N. Robertson, and Craig Newtson. "Properties of Concrete
Produced with Admixtures Intended to Inhibit Corrosion." Research Report UHM/CEE/01‐01, Department of Civil and Environmental Engineering, University of Hawaii at Manoa College of Engineering, 2001.
87
Portland Cement Association. PCA Concrete Technology | Durability: Corrosion on
Embedded Metals. 2012. http://www.cement.org/tech/cct_dur_corrosion.asp (accessed September 2012).
Roberge, P.R. Corrosion Basics An Introduction. Houston, Texas: NACE
International, 2006. Robertson, Ian N. "Improving Concrete Durability through the use of Corrosion
Inhibitors." Paper presented at the 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, IRRCCC 2012, held in Cape Town, South Africa, September 3‐5, 2012, Department of Civil and Environmental Engineering, University of Hawaii at Manoa, College of Engineering, 2012.
Ropert, Joshua, and Ian N. Robertson. "Performance of Corrosion Inhibiting
Admixtures in Hawaiian COncrete in a Marine Environment." Research Report UHM/CEE/12‐XX, Department of Civil and Environmental Engineering, University of Hawaii at Manoa College of Engineering, 2012.
Sagues, Ph.D, P.E, Alberto. "Metallurgical Effects on Chloride Ion Corrosion
Threshold of Steel in Concrete." Summary of Final Report, WPI# 0510806, University of South Florida, 2001.
Schmitt, Günter. "Global Needs for Knowledge Dissemination, Research, and
Development in Materials Deterioration and Corrosion Control." World Corrosion Organization. 2009. http://www.corrosion.org/images_index/whitepaper.pdf (accessed 2012).
Slater, John E. Corrosion of Metals in Association with Concrete. Edited by STP‐81
ASTM. 1983. Smith, J. L., and Y. P. Virmani. "Materials and Methods for Corrosion Control of
Reinforced and Prestressed Concrete Structures in New Construction." Report FHWA‐RD‐00‐081, Federal Highway Administration, 2001.
Song, Ha‐Won, and Velu Saraswathy. "Corrosion Monitoring of Reinforced Concrete
Structures ‐ A Review." International Journal of Electrochemical Science 2 (2007): 1‐28.
Stanish, K.D., R.D. Hooton, and M.D.A. Thomas. "Testing the Chloride Penetration
Resistance of Concrete: A Literature Review." FHWA Contract DTFH61‐97‐R‐00022 “Prediction of Chloride Penetration in Concrete”, University of Toronto, Department of Civil Engineering.
Stratfull, R.R. "The Corrosion of Steel in a Reinforced Concrete Bridge, Corrosion."
Vol. 13, no. 3 (1957): pp 173‐178.
88
Uno, John, Ian N. Robertson, and Craig Newtson. "Corrosion Susceptibility of
Concrete Exposed to a Marine Environment." Research Report UHM/CEE/04‐09, Department of Civil and Environmetal Engineering, University of Hawaii at Manoa College of Engineering, 2004.
Wight, James K., and James G. MacGregor. "Reinforced Concrete Mechanics &
Design." Pearson Prentice Hall, 2009. World Corrosion Organization. "Corrosion Comprehension: "Combating the
Pervasive Menace"." Corrosion Videos World Corrosion Organization. 2012. http://www.corrosion.org/video.asp (accessed 2012).
89
APPENDIX B Field panel half-cell readings and visual observations
Figure B - 1: Panel 1 Kapaa Contol 0.40 w/c Half-Cell Reading September 2009
0
50
100
150
200
250
300
350
400
450
Ave
rag
e H
alf
Cel
l (
-0.
001m
V).
Distance from top of panel (cm)
Panel #1: Kapaa Control with 0.4 w/c ratio
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Crack Observed
90
Figure B - 2: Panel 2 Halawa Control 0.40 w/c Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #2: Halawa Control with 0.40 w/c ratio
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #2: Halawa Control 0.40 w/c
91
Figure B - 3: Panel 3 Kapaa 0.40 w/c DCI 2 gal/cy Half-Cell Reading September 2009
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #3: Kapaa 0.40 w/c with DCI 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
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
92
Figure B - 4: Panel 3A Kapaa 0.40 w/c DCI 4 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #3A: Kapaa 0.40 w/c with DCI at 20l/m3 (4 gal/cuyd)
1.1 years
2.4 years
3.2 years
3.6 years
4.3 years
4.8 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
S…
S…
S…
S…
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #3A: Kapaa 0.40 w/c with 4 gal/cuyd DCI
93
Figure B - 5: Panel 4 Halawa 0.40 w/c DCI 2 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #4: Halawa 0.40 w/c with DCI 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
9.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
5
6
Panel #4: Halawa 0.40 w/c with 2 gal/cuyd DCI
94
Figure B - 6: Panel 5 Kapaa 0.40 w/c CNI 2 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
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
9.5 years Rust Observed
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
0
50
100
150
200
250
300
350
400
450
1
2
3
4
5
6
Panel #5: Kapaa 0.40 w/c with 2 gal/cuyd CNI
95
Figure B - 7: Panel 5A Kapaa 0.40 w/c CNI 4 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #5A: Kapaa 0.40 w/c with CNI at 20l/m3 (4 gal/cuyd)
0.7 years
2.5 years
3.2 years
3.6 years
4.3 years
4.7 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #5A: Kapaa 0.40 w/c with 4 gal/cuyd CNI
96
Figure B - 8: Panel 6 Kapaa 0.40 w/c CNI 2 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #6: Kapaa 0.40 w/c with CNI at 10 l/m3 (2 gal/cuyd)
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.3 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #6: Kapaa 0.40 w/c with 2 gal/cuyd CNI
97
Figure B - 9: Panel 7 Control 0.35 w/c Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #7: Kapaa Control with 0.35 w/c ratio
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #7: Kapaa Control 0.35 w/c
98
Figure B - 10: Panel 8 Kapaa 0.36 w/c 5% Silica Fume (MB) Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #8: Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.2 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #8: Kapaa 0.36 w/c with 5% Silica Fume (MB)
99
Figure B - 11: Panel 9 Kapaa 0.36 w/c 5% Silica Fume (MB) Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #9: Kapaa 0.36 w/c with 5% Silica Fume (Master Builders)
1.1 years
2.4 years
3.2 years
3.6 years
4.3 years
4.8 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #9: Kapaa 0.36 w/c with 5% Silica Fume (MB)
100
Figure B - 12: Panel 10 Kapaa 0.36 w/c 5% Silica Fume (Grace) Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #10: Kapaa 0.36 w/c with 5% Silica Fume (Grace)
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.2 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #10: Kapaa 0.36 w/c with 5% Silica Fume (Grace)
101
Figure B - 13: Panel 11 Kapaa 0.36 w/c 15% Fly Ash Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #11: Kapaa 0.36 w/c with 15% Fly Ash
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.3 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #11: Kapaa 0.36 w/c with 15% Fly Ash
102
Figure B - 14: Panel 12 Halawa 0.36 w/c 15% Fly Ash Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #12: Halawa 0.36 w/c with 15% Fly Ash
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #12: Halawa 0.36 w/c with 15% Fly Ash
103
Figure B - 15: Panel 13 Halawa 0.36 w/c 15% Fly Ash Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #13: Halawa 0.36 w/c with 15% Fly Ash
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
3
4
5
6
Panel #13: Halawa 0.36 w/c with 15% Fly Ash
104
Figure B - 16: Panel 14 Kapaa 0.40 w/c 5% Latex Modifier Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #14: Kapaa 0.40 w/c with 5% Latex Modifier
2.4 years
3.2 years
3.6 years
4.3 years
4.8 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
1
2
3
4
5
6
Panel #14: Kapaa 0.40 w/c with 5% Latex Modifier
105
Figure B - 17: Panel 15 Kapaa 0.40 w/c Rheocrete 222+ 1 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
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 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.5 years
< 10%
> 90%
50%
Probability of corrosion.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
1
2
3
4
5
6
Panel #15: Kapaa 0.40 w/c with Rheocrete 222+ at 1 gal/cuyd
106
Figure B - 18: Panel 16 Kapaa 0.40 w/c Rheocrete 222+ 1 gal/cy Half-Cell Reading September 2009
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
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 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.5 years
< 10%
> 90%
50%
Probability of corrosion.
19 110886542 133
107
Figure B - 19: Panel 17 Halawa 0.40 w/c Rheocrete 222+ 1 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
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 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.5 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
1
2
3
4
5
6
Panel #17: Halawa 0.40 w/c with Rheocrete 222+ at 1 gal/cuyd
108
Figure B - 20: Panel 17A Halawa 0.40 w/c Rheocrete 222+ 1 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
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 years
2.4 years
3.2 years
3.6 years
4.3 years
4.8 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
3
4
5
6
Panel #17A: Halawa 0.40 w/c with Rheocrete 222+ at 1 gal/cuyd
109
Figure B - 21: Panel 18 Halawa 0.40 w/c Ferrogard 3 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #18: Halawa 0.40 w/c with Ferrogard at 15 l/m3 (3 gal/cuyd)
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #18: Halawa 0.40 w/c with Ferrogard at 3 gal/cuyd
110
Figure B - 22: Panel 19 Halawa 0.40 w/c Ferrogard 3 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #19: Halawa 0.40 w/c with Ferrogard at 15 l/m3 (3 gal/cuyd)
2.0 years
3.4 years
4.1 years
4.5 years
5.2 years
5.6 years
7.0 years
9.6 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #19: Halawa 0.40 w/c with Ferrogard at 3 gal/cuyd
111
Figure B - 23: Panel 20 Kapaa 0.40 w/c Ferrogard 3 gal/cy Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #20: Kapaa 0.40 w/c with Ferrogard at 15 l/m3 (3 gal/cuyd)
0.0 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.7 years
9.3 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed
0
50
100
150
200
250
300
350
400
450
12
3
4
5
6
Panel #20: Kapaa 0.40 w/c with Ferrogard at 3 gal/cuyd
112
Figure B - 24: Panel 21 Kapaa 0.40 w/c 2% Xypex Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #21: Kapaa 0.40 w/c with 2% Xypex
1.7 years
3.1 years
3.8 years
4.2 years
5.0 years
5.3 years
6.8 years
9.3 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Rust Observed after 7 years
0
50
100
150
200
250
300
350
400
450
12
3
4
5
6
Panel #21: Kapaa 0.40 w/c with 2% Xypex
113
Figure B - 25: Panel 22 Kapaa 0.40 w/c 2% Kryton KIM Half-Cell Reading March 2012
0
50
100
150
200
250
300
350
400
450A
vera
ge
Hal
f C
ell
(-
0.00
1mV
).
Distance from top of panel (cm)
Panel #22: Kapaa 0.40 w/c with 2% Kryton KIM
1.1 years
2.4 years
3.2 years
3.6 years
4.3 years
4.8 years
6.2 years
8.7 years
< 10%
> 90%
50%
Pro
bab
ility
of
corr
osi
on
.
19 110886542 133
Crack Observed
0
50
100
150
200
250
300
350
400
450
12
34
56
Panel #22: Kapaa 0.40 w/c with 2% Kryton KIM
114
115
APPENDIX C Final Panel Photos
Figure C - 1: Panel 1 Kapaa Control with 0.4 w/c ratio at 7.0 years exposure
Figure C - 2: Panel 2 Halawa Control 0.40 w/c All Surfaces
116
Figure C - 3: Panel 2 Halawa Control 0.40 w/c Front Surface Rusts and Cracks
Figure C - 4: Panel 2 Halawa Control 0.40 w/c Right Surface Rusts
117
Figure C - 5: Panel 3 Kapaa 0.40 w/c ratio with 2 gal/cuyd at 7.0 years exposure
Figure C - 6: Panel 3A Kapaa 0.40 w/c with 4 gal/cuyd DCI All Surfaces
118
Figure C - 7: Panel 3A Kapaa 0.40 w/c with 4 gal/cuyd DCI Front Surface Rust
Figure C - 8: Panel 3A Kapaa 0.40 w/c with 4 gal/cuyd DCI Right Surface Rust
119
Figure C - 9: Panel 4 Halawa 0.40 w/c with 2 gal/cy DCI All Surfaces
Figure C - 10: Panel 4 Halawa 0.40 w/c with 2 gal/cy DCI Front Surface Rust and Crack
120
Figure C - 11: Panel 4 Halawa 0.40 w/c with 2 gal/cy DCI Left Surface Rust
Figure C - 12: Panel 4 Halawa 0.40 w/c with 2 gal/cy DCI Back Surface Rust and Cracks
121
Figure C - 13: Panel 5 Kapaa 0.40 w/c with 2 gal/cy CNI All Surfaces
Figure C - 14: Panel 5 Kapaa 0.40 w/c with 2 gal/cy CNI Right Surface Rust
122
Figure C - 15: Panel 5A Kapaa 0.40 w/c with 4 gal/cy CNI All Surfaces
Figure C - 16: Panel 6 Kapaa 0.40 w/c with 2 gal/cy CNI All Surfaces
123
Figure C - 17: Panel 6 Kapaa 0.40 w/c with 2 gal/cy CNI Front Surface Rust and Cracks
Figure C - 18: Panel 7 Kapaa Control 0.35 w/c All Surfaces
124
Figure C - 19: Panel 7 Kapaa Control 0.35 w/c Front Surface Rust
Figure C - 20: Panel 8 Kapaa 0.36 w/c with 5% Silica Fume (MB) All Surfaces
125
Figure C - 21: Panel 8 Kapaa 0.36 w/c with 5% Silica Fume (MB) Back Surface Rust
Figure C - 22: Panel 8 Kapaa 0.36 w/c with 5% Silica Fume (MB) Left Surface Rust
126
Figure C - 23: Panel 9 Kapaa 0.36 w/c with 5% Silica Fume All Surfaces
Figure C - 24: Panel 9 Kapaa 0.36 w/c with 5% Silica Fume Front Surface Crack
127
Figure C - 25: Panel 11 Kapaa 0.36 w/c with 15% Fly Ash All Surfaces
Figure C - 26: Panel 11 Kapaa 0.36 w/c with 15% Fly Ash Left and Right Surface Cracks
128
Figure C - 27: Panel 11 Kapaa 0.36 w/c with 15% Fly Ash Back Surface Rust
Figure C - 28: Panel 12 Halawa 0.36 w/c with 15% Fly Ash All Surfaces
129
Figure C - 29: Panel 12 Halawa 0.36 w/c with 15% Fly Ash Back Surface Rust and Cracks
Figure C - 30: Panel 13 Halawa 0.36 w/c with 15% Fly Ash All Surfaces
130
Figure C - 31: Panel 13 Halawa 0.36 w/c with 15% Fly Ash Right Surface Rust
Figure C - 32: Panel 14 Kapaa 0.40 w/c with 5% Latex Modifier All Surfaces
131
Figure C - 33: Panel 14 Kapaa 0.40 w/c with 5% Latex Modifier Front Surface Rust and Crack
Figure C - 34: Panel 14 Kapaa 0.40 w/c with 5% Latex Modifier Back Surface Crack
132
Figure C - 35: Panel 14 Kapaa 0.40 w/c with 5% Latex Modifier Right Surface Rust
Figure C - 36: Panel 15 Kapaa 0.40 w/c with Rheocrete 222+ 1 gal/cy All Surfaces
133
Figure C - 37: Panel 15 Kapaa 0.40 w/c with Rheocrete 222+ 1 gal/cy Front Surface Cracks
C - 38: Panel 15 Kapaa 0.40 w/c with Rheocrete 222+ 1 gal/cy Left and Right Surface Rust
and Cracks
134
Figure C - 39: Panel 16 Kapaa 0.40 w/c with Rheocrete 222+ at 5 l/m3 (1 gal/cuyd) at 7.0 years exposure
Figure C - 40: Panel 17A Halawa 0.40 w/c with Rheocrete 222+ 1 gal/cy All Surfaces
135
Figure C - 41: Panel 17A Halawa 0.40 w/c with Rheocrete 222+ 1 gal/cy Front Surface
Crack
Figure C - 42: Panel 17A Halawa 0.40 w/c with Rheocrete 222+ 1 gal/cy Left and Right
Surface Crack and Rust
136
Figure C - 43: Panel 18 Halawa 0.40 w/c with Ferrogard 3 gal/cy All Surfaces
Figure C - 44: Panel 18 Halawa 0.40 w/c with Ferrogard 3 gal/cy Front Surface Cracks and Rust
137
Figure C - 45: Panel 18 Halawa 0.40 w/c with Ferrogard 3 gal/cy Back Surface Rust
138
Figure C - 46: Panel 19 Halawa 0.40 w/c with Ferroard 3 gal/cy All Surfaces
Figure C - 47: Panel 19 Halawa 0.40 w/c with Ferroard 3 gal/cy Left and Right Surface Rust and Crack
Figure C - 48: Panel 19 Halawa 0.40 w/c with Ferroard 3 gal/cy Front Surface Cracks
139
Figure C - 49: Panel 19 Halawa 0.40 w/c with Ferroard 3 gal/cy Bottom Surface Rust
Figure C - 50: Panel 20 Kapaa 0.40 w/c with Ferrogard 3 gal/cy All Surfaces
Figure C - 51: Panel 20 Kapaa 0.40 w/c with Ferrogard 3 gal/cy Front Surface Rust
140
Figure C - 52: Panel 20 Kapaa 0.40 w/c with Ferrogard 3 gal/cy Right Surface Rust
Figure C - 53: Panel 20 Kapaa 0.40 w/c with Ferrogard 3 gal/cy Back Surface Cracks and Rust
141
Figure C - 54: Panel 21 Kapaa 0.40 w/c with 2% Xypex All Surfaces
Figure C - 55: Panel 21 Kapaa 0.40 w/c with 2% Xypex Left and Front Surface Rust
142
Figure C - 56: Panel 22 Kapaa 0.40 w/c with 2% Kryton KIM All Surfaces
Figure C - 57: Panel 22 Kapaa 0.40 w/c with 2% Kryton KIM Left Surface Cracks
143
APPENDIX D
Reinforcing Bar Photos
144
Figu
re D2 - 1: P
anel 2 H
alawa C
ontrol 0.40 w
/c
145
Figu
re D2 - 2: P
anel 2 C
orrosion L
ocation an
d L
ength
s
146
Figu
re D2 - 3: P
anel 2 T
op L
ayer Top
Su
rface
147
Figu
re D2 - 4: P
anel 2 T
op L
ayer Bottom
Su
rface
148
Figu
re D2 - 5: P
anel 2 B
ottom L
ayer Bottom
Su
rface
149
Figu
re D2 - 6: P
anel 2 B
ottom L
ayer Top
Su
rface
150
Figu
re D3A
- 1: Pan
el 3A K
apaa 0.40 w
/c with
4 gal/cy DC
I
151
Figu
re D3A
- 2: Pan
el 3A C
orrosion L
ocation an
d L
ength
s
152
Figu
re D3A
- 3: Pan
el 3A T
op L
ayer Top
and
Bottom
Su
rfaces
153
Figu
re D4 - 1: P
anel 4 H
alawa 0.40 w
/c with
2 gal/cy DC
I
154
Figu
re D4 - 2: P
anel 4 C
orrosion L
ocation an
d L
ength
s
155
Figu
re D4 - 3: P
anel 4 T
op L
ayer Top
Su
rface
156
Figu
re D4 - 4: P
anel 4 T
op L
ayer Bottom
Su
rface
157
Figu
re D4 - 5: P
anel 4 B
ottom L
ayer Bottom
Su
rface
158
Figu
re D4 - 6: P
anel 4 B
ottom L
ayer Top
Su
rface
159
Figu
re D5 - 1: P
anel 5 K
apaa 0.40 w
/c with
2 gal/cy CN
I
160
Figu
re D5 - 2: P
anel 5 C
orrosion L
ocation an
d L
ength
s
161
Figu
re D5 - 3: P
anel 5 T
op L
ayer Top
Su
rface
162
Figu
re D5 - 4: P
anel 5 T
op L
ayer Bottom
Su
rface
163
Figu
re D5 - 5: P
anel 5 B
ottom L
ayer Bottom
and
Top
Su
rface
164
Figu
re D5A
- 1: Pan
el 5A K
apaa 0.40 w
/c with
4 gal/cy CN
I
165
Figu
re D5A
- 2: Pan
el 5A C
orrosion L
ocation an
d L
ength
s
166
Figu
re D5A
- 3: Pan
el 5A T
op L
ayer Top
and
Bottom
Su
rface
167
Figu
re D6 - 1: P
anel 6 K
apaa 0.40 w
/c with
2 gal/cy CN
I
168
Figu
re D6 - 2: P
anel 6 C
orrosion L
ocation an
d L
ength
s
169
Figu
re D6 - 3: P
anel 6 T
op L
ayer Top
Su
rface
170
Figu
re D6 - 4: P
anel 6 T
op L
ayer Bottom
Su
rface
171
Figu
re D7 - 1: P
anel 7 K
apaa C
ontrol 0.35 w
/c
172
Figu
re D7 - 2: P
anel 7 C
orrosion L
ocation an
d L
ength
s
173
Figu
re D7 - 3: P
anel 7 T
op L
ayer Top
Su
rface
174
Figu
re D7 - 4: P
anel 7 T
op L
ayer Bottom
Su
rface
175
Figu
re D7 - 5: P
anel 7 B
ottom L
ayer Top
and
Bottom
Su
rface
176
Figu
re D8 - 1: P
anel 8 K
apaa 0.36 w
/c with
5% S
ilica Fu
me (M
B)
177
Figu
re D8 - 2: P
anel 8 C
orrosion L
ocation an
d L
ength
s
178
Figu
re D8 - 3: P
anel 8 T
op L
ayer Top
Su
rface
179
Figu
re D8 - 4: P
anel 8 T
op an
d B
ottom L
ayer Bottom
Su
rface
180
Figu
re D9 - 1: P
anel 9 K
apaa 0.36 w
/c with
5% S
ilica Fu
me (M
B)
181
Figu
re D9 - 2: P
anel 9 C
orrosion L
ocation an
d L
ength
s
182
Figu
re D9 - 3: P
anel 9 T
op L
ayer Top
Su
rface
183
Figu
re D9 - 4: P
anel 9 T
op L
ayer Bottom
Su
rface
184
Figu
re D10 - 1: P
anel 10 K
apaa 0.36 w
/c with
5% S
ilica Fu
me (G
race)
185
Figu
re D10 - 2: P
anel 10 C
orrosion L
ocation an
d L
ength
s
186
Figu
re D10 - 3: P
anel 10 T
op L
ayer Top
Su
rface
187
Figu
re D10 - 4: P
anel 10 T
op L
ayer Bottom
Su
rface
188
Figu
re D10 - 5: P
anel 10 B
ottom L
ayer Bottom
Su
rface
189
Figu
re D10 - 6: P
anel 10 B
ottom L
ayer Top
Su
rface
190
Figu
re D11 - 1: P
anel 11 K
apaa 0.36 w
/c with
15% F
ly Ash
191
Figu
re D11 - 2: P
anel 11 C
orrosion L
ocation an
d L
ength
s
192
Figu
re D11 - 3: P
anel 11 T
op L
ayer Top
and
Bottom
Su
rface
193
Figu
re D11 - 4: P
anel 11 B
ottom L
ayer Bottom
and
Top
Su
rface
194
Figu
re D12 - 1: P
anel 12 H
alawa 0.36 w
/c with
15% F
ly Ash
195
Figu
re D12 - 2: P
anel 12 C
orrosion L
ocation an
d L
ength
s
196
Figu
re D12 - 3: P
anel 12 T
op L
ayer Top
and
Bottom
Su
rface
197
Figu
re D13 - 1: P
anel 13 H
alawa 0.36 w
/c with
15% F
ly Ash
198
Figu
re D13 - 2: P
anel 13 C
orrosion L
ocation an
d L
ength
s
199
Figu
re D14 - 1: P
anel 14 K
apaa 0.40 w
/c with
5% L
atex Mod
ifier
200
Figu
re D14 - 2: P
anel 14 C
orrosion L
ocation an
d L
ength
s
201
Figu
re D14 - 3: P
anel 14 T
op L
ayer Bottom
Su
rface
202
Figu
re D14 -4: P
anel 14 T
op L
ayer Top
Su
rface, Bottom
Layer B
ottom S
urface
203
Figu
re D15 - 1: P
anel 15 K
apaa 0.40 w
/c with
Rh
eocrete 222+ at 1 gal/cy
204
Figu
re D15 - 2: P
anel 15 C
orrosion L
ocation an
d L
ength
s
205
Figu
re D15 - 3: P
anel 15 T
op L
ayer Top
and
Bottom
Su
rface
206
Figu
re D17 - 1: P
anel 17 H
alawa 0.40 w
/c with
Rh
eocrete 222+ at 1 gal/cy
F
igure D
17 -1: Pan
el 17 Halaw
a 0.40 w/c w
ith R
heocrete 222+
at 1 gal/cy
207
Figu
re D17 - 2: P
anel 17 C
orrosion L
ocation an
d L
ength
s
208
Figu
re D17 - 3: P
anel 17 T
op L
ayer Top
Su
rface
209
Figu
re D17 - 4: P
anel 17 T
op L
ayer Bottom
Su
rface
210
Figu
re D17 - 5: P
anel 17 B
ottom L
ayer Bottom
Su
rface
211
Figu
re D17 - 6: P
anel 17 B
ottom L
ayer Top
Su
rface
212
Figu
re D17A
- 1: Pan
el 17A H
alawa 0.40 w
/c with
Rh
eocrete 222+ at 1 gal/cy
213
Figu
re D17A
- 2: Pan
el 17A C
orrosion L
ocation and
Len
gths
214
Figu
re D17A
- 3: Pan
el 17A T
op L
ayer Top
Su
rface
215
Figu
re D17A
- 4: Pan
el 17A T
op L
ayer Bottom
Su
rface
216
Figu
re D18 - 1: P
anel 18 H
alawa 0.40 w
/c with
Ferrogard
at 3 gal/cy
217
Figu
re D18 - 2: P
anel 18 C
orrosion L
ocation an
d L
ength
s
218
Figu
re D18 - 3: P
anel 18 T
op L
ayer Top
Su
rface
219
Figu
re D18 - 4: P
anel 18 T
op L
ayer Bottom
Su
rface
220
Figu
re D18 - 5: P
anel 18 B
ottom L
ayer Bottom
Su
rface
221
Figu
re D18 - 6: P
anel 18 B
ottom L
ayer Top
Su
rface
222
Figu
re D19 - 1: P
anel 19 H
alawa 0.40 w
/c with
Ferrogard
at 3 gal/cy
223
Figu
re D19 - 2: P
anel 19 C
orrosion L
ocation an
d L
ength
s
224
Figu
re D19 - 3: P
anel 19 T
op L
ayer Top
Su
rface
225
Figu
re D19 - 4: P
anel 19 T
op L
ayer Bottom
Su
rface
226
Figu
re D19 - 5: P
anel 19 B
ottom L
ayer Bottom
and
Top
Su
rface
227
Figu
re D20 - 1: P
anel 20 K
apaa 0.40 w
/c with
Ferrogard
at 3 gal/cy
228
Figu
re D20 - 2: P
anel 20 C
orrosion L
ocation an
d L
ength
s
229
Figu
re D20 - 3: P
anel 20 T
op L
ayer Top
Su
rface
230
Figu
re D20 - 4: P
anel 20 T
op L
ayer Bottom
Su
rface
231
Figu
re D21 - 1: P
anel 21 K
apaa 0.40 w
/c with
2% X
ypex
232
Figu
re D21 - 2: P
anel 21 C
orrosion L
ocation an
d L
ength
s
233
Figu
re D21 - 3: P
anel 21 T
op L
ayer Top
Su
rface
234
Figu
re D21 - 4: P
anel 21 T
op L
ayer Bottom
Su
rface
235
Figu
re D21 - 5: P
anel 21 B
ottom L
ayer Bottom
Su
rface
236
Figu
re D21 - 6: P
anel 21 B
ottom L
ayer Top
Su
rface
237
Figu
re D22 - 1: P
anel 22 K
apaa 0.40 w
/c with
2% K
ryton K
IM
238
Figu
re D22 - 2: P
anel 22 C
orrosion L
ocation an
d L
ength
s
239
Figu
re D22 - 3: P
anel 22 T
op L
ayer Top
Su
rface
240
Figu
re D22 - 4: P
anel 22 T
op L
ayer Bottom
Su
rface
241