.tfhrc.gov/structur/pubs/04090/04090.pdf. It's a snapshot of the page taken as our search engine crawled the Web.
The web site itself may have changed. You can check the current page or check for previous versions at the Internet Archive. Yahoo! is not affiliated with the authors of this page or responsible for its content.
Long-Term Performance of Epoxy-Coated Reinforcing Steel in Heavy Salt-Contaminated Concrete Long-Term Performance of
Epoxy-Coated Reinforcing Steel in
Heavy Salt-Contaminated Concrete
PUBLICATION NO. FHWA-HRT-04-090
JUNE 2004
Research, Development, and Technology
Turner-Fairbank Highway Research Center
6300 Georgetown Pike
McLean, VA 22101-2296
1. Report No.
FHWA-HRT-04-090
2. Government
Accession
No.



3. Recipients
Catalog
No.



4. Title and Subtitle
Long-Term Performance of Epoxy-Coated Reinforcing Steel in Heavy Salt-
Contaminated Concrete
5. Report
Date
June 2004

6.
Performing Organization Code

7.
Author(s)
Seung-Kyoung Lee, Paul D. Krauss

8. Performing Organization Report No.


9. Performing Organization Name and Address
WISS, Janney, Elstner Associates, Inc.
330 Pfingsten Road
Northbrook, IL 60062-2095

10.
Work Unit No. (TRAIS)


11.
Contract or Grant No.
DTFH61-93-C-00027
12. Sponsoring Agency Name and Address
Office of Infrastructure R&D
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296

13.
Type of Report and Period Covered
Final Report
September 1998 to December 2002
14. Sponsoring
Agency
Code
15. Supplementary Notes
Contracting Officers Technical Representative (COTR): Yash Paul Virmani, HRDI-10
Acknowledgements: Leo Zegler, John Drakeford, Gregory Hedien, Steve Harris, Steve Zimmerman

16. Abstract
This report describes long-term natural weathering exposure testing of the remaining 31 post-Southern Exposure (SE) test slabs that were
not autopsied during the 19931998 Federal Highway Administration (FHWA) research project. The samples were exposed from
September 1998 to December 2002 at an outdoor test yard in Northbrook, IL. The 19931998 research program involved testing more
than 52 different bar materials and, consequently, 12 different bar types were selected for long-term durability tests in concrete exposed
to the very aggressive SE test, which involved alternating wetting with 15 weight percent NaCl solution and drying cycles for 96 weeks.
Periodic macrocell corrosion current between top and bottom mats and short-circuit potential data were collected during the exposure test
rogram. Upon termination of the test program, autopsy and subsequent laboratory analysis was performed on the test slabs.
p

The test results confirmed that the black bars produced the highest mean macrocell current density (least corrosion resistant) among
various combinations of test variables regardless of slab configuration, and that the stainless steel bars exhibited negligible mean
macrocell current density. In general, bent epoxy-coated reinforcing bar (ECR) in the top mat, coupled with black bars in the bottom
mat, performed the worst among all ECR cases. The straight top-mat ECRs macrocell current density varied from 7 to 40 percent of the
highest black bar case, depending on the size of initial coating damage and type of bar in the bottom mat. ECR used in the top mat alone
reduced the corrosion susceptibility to at least 50 percent of the black bar case, even when it contained coating damage and was
connected to the black bar bottom mat. In contrast, if straight ECRs in the top mat were connected to ECRs in the bottom mat, the mean
macrocell current density was no greater than 2 percent of the highest black bar case even when rebar coatings had defects, and approach
the corrosion resistant level of stainless steel reinforcement. Such improved corrosion resistance can be attributed to (1) reduction in
cathodic area; (2) higher electrical resistance; and (3) reduced cathodic reaction.

Whenever an ECR slab with negligible macrocell current density was autopsied, the appearance of the extracted ECR and concrete/bar
interface was excellent with no sign of corrosion. However, when ECRs specimens with high macrocell current densities were
autopsied, they revealed coating deterioration due to corrosion and exhibited numerous hairline cracks and/or blisters in conjunction with
reduced adhesion, coating disbondment (permanent adhesion loss), and underlying steel corrosion. No consistent trend was found
between the level of macrocell current density and the extent of coating adhesion loss. The present test results and the earlier FHWA
studies indicate that adhesion appeared to be a poor indicator of long-term performance of the coated bars in chloride contaminated
concrete; it is concluded that there is no direct relationship between loss of adhesion and the effectiveness of ECR to mitigate corrosion.

Key Words
concrete, corrosion, durability, electrochemical impedance
spectroscopy, black bar, stainless steel, epoxy-coated reinforcing
steel, mat-to-mat resistance, macrocell current, corrosion rate,
chloride
18. Distribution Statement
No restrictions. This document is available to the public through
the National Information Service, Springfield, VA 22161.
19. Security Classif. (of this report)
Unclassified
20. Security Classif. (of this page)
Unclassified
21. No. of Pages
130
22. Price


Form DOT F 1700.7 (8-72)
Reproduction of completed page authorized
SI* (MODERN METRIC) CONVERSION FACTORS
APPROXIMATE CONVERSIONS TO SI UNITS
Symbol When
You
Know
Multiply
By
To
Find
Symbol
LENGTH
in inches
25.4 millimeters
mm
ft feet
0.305
meters
m
yd yards
0.914
meters
m
mi miles
1.61 kilometers
km
AREA
in
2
square inches
645.2
square millimeters
mm
2
ft
2
square feet
0.093
square meters
m
2
yd
2
square yard
0.836
square meters
m
2
ac
acres
0.405
hectares
ha
mi
2
square miles
2.59
square kilometers
km
2
VOLUME
fl oz
fluid ounces
29.57
milliliters
mL
gal gallons
3.785 liters
L
ft
3
cubic feet
0.028
cubic meters
m
3
yd
3
cubic yards
0.765
cubic meters
m
3
NOTE: volumes greater than 1000 L shall be shown in m
3
MASS
oz
ounces
28.35
grams
g
lb
pounds 0.454
kilograms
kg
T
short tons (2000 lb)
0.907
megagrams (or "metric ton")
Mg (or "t")
TEMPERATURE (exact degrees)
o
F Fahrenheit
5
(F-32)/9
Celsius
o
C
or (F-32)/1.8
ILLUMINATION
fc
foot-candles
10.76
lux
lx
fl
foot-Lamberts
3.426
candela/m
2
cd/m
2
FORCE and PRESSURE or STRESS
lbf
poundforce
4.45
newtons
N
lbf/in
2
poundforce per square inch
6.89
kilopascals
kPa
APPROXIMATE CONVERSIONS FROM SI UNITS
Symbol
When You Know
Multiply By
To Find
Symbol
LENGTH
mm millimeters
0.039 inches
in
m meters
3.28 feet
ft
m meters
1.09 yards
yd
km kilometers
0.621 miles
mi
AREA
mm
2

square millimeters
0.0016
square inches
in
2
m
2

square meters
10.764
square feet
ft
2
m
2
square
meters
1.195
square
yards
yd
2
ha hectares
2.47
acres
ac
km
2
square kilometers
0.386
square miles
mi
2
VOLUME
mL
milliliters
0.034
fluid ounces
fl oz
L liters
0.264
gallons
gal
m
3
cubic meters
35.314
cubic feet
ft
3
m
3
cubic meters
1.307
cubic yards
yd
3
MASS
g
grams
0.035
ounces
oz
kg
kilograms
2.202
pounds
lb
Mg (or "t")
megagrams (or "metric ton")
1.103
short tons (2000 lb)
T
TEMPERATURE (exact degrees)
o
C Celsius
1.8C+32
Fahrenheit
o
F
ILLUMINATION
lx
lux
0.0929
foot-candles
fc
cd/m
2
candela/m
2
0.2919 foot-Lamberts
fl
FORCE and PRESSURE or STRESS
N newtons
0.225
poundforce
lbf
kPa
kilopascals
0.145
poundforce per square inch
lbf/in
2
*SI is the symbol for th International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380.
e
(Revised March 2003
)

ii
TABLE OF CONTENTS


EXECUTIVE SUMMARY ...........................................................................................................1

CHAPTER 1. INTRODUCTION AND PROJECT HISTORY ................................................3

CHAPTER 2. EXPERIMENTAL METHOD ...........................................................................11
Test Specimens ........................................................................................................................11
Data Collection ........................................................................................................................11
Autopsy....................................................................................................................................13
Chloride Analysis.....................................................................................................................14

CHAPTER 3. RESULTS AND DISCUSSION......................................................................... 15
Short-Circuit Potential and Macrocell Current Density...........................................................15
Statistical Analysis of Test Data ..............................................................................................18
Autopsy Resu