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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iii 

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 

xii 

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 

 

 1

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

 

 2

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.

 

 3

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.

 

 5

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

 

 6

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

 

 7

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

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on

.

19 110886542 133

Rust Observed

0

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450

12

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56

Panel #2: Halawa Control 0.40 w/c

 

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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

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of

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on

.

19 110886542 133

Rust Observed

0

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100

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12

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56

Panel #7: Kapaa Control 0.35 w/c

 

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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

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of

corr

osi

on

.

19 110886542 133

Rust Observed

0

50

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150

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250

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350

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450

12

34

5

6

Panel #4: Halawa 0.40 w/c with 2 gal/cuyd DCI

 

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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

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19 110886542 133

0

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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

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on

.

19 110886542 133

0

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12

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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

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150

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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

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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

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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

 

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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

 

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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.

 

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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

 

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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

 

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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

 

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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

 

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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

 

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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

 

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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

 

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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.

 

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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

 

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Figure 4-49: Panel 10 Reinforcing Steel Top and Bottom Layers

Figure 4-50: Panel 10 Corrosion Location and Lengths

 

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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

 

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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

 

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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

 

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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

 

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Figure 4-58: Panel 11 Corrosion Location and Lengths

Figure 4-59: Panel 11 Top Layer Top and Bottom Surfaces – Corrosion on Reinforcing Steel

 

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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.

 

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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

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 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 

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 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 

 

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 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. 

 

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 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. 

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 Schmitt, Günter. "Global Needs for Knowledge Dissemination, Research, and 

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 Song, Ha‐Won, and Velu Saraswathy. "Corrosion Monitoring of Reinforced Concrete 

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 Stanish, K.D., R.D. Hooton, and M.D.A. Thomas. "Testing the Chloride Penetration 

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 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