ASPIRE Fall 2012 - Aspire - The Concrete Bridge Magazine

Epoxy-Coated
reinforcing
Type 205
Stainless-Steel
reinforcing
75 Year Cost
Uncoated
reinforcing
EPOXY INTEREST GROUP
®
®
1 0%
80%
60%
40%
20%
1 0%
80%
60%
40%
20%
1 0%
80%
60%
40%
20%
bridges.
Epoxy Coating Thickness
Active co rosion
No active co rosion
0% 2 4 6 8 10 12 14 16 18
Thickne s (mil)
Chloride At Bar Level
Epoxy-Coated: active corrosion
Uncoated: active co rosion
Epoxy-Coated: no active co rosion
Uncoated: no active co rosion
Cumulative distribution
0% 0 0.05 0.1 0.15 0.2 0.25 0.3
Chloride (% by wt. concrete)
0% -60 -50 -40 -30 -20 -10 10
Time (years)
Epoxy-coating
thickne s test.
Epoxy-Coated: active co rosion
Epoxy-Coated: no active co rosion
Uncoated: active co rosion
Uncoated: no active co rosion
Cumulative distribution
Cumulative distribution
The analysis evaluated:
• Cover
• Coating adhesion and backside cleanline s
• Coating thickne s
• Chloride concentration at bar depth
• Time since chloride concentration exc eded black bar
threshold
standards.
ANALySIS OF BAR CONDITIONS
02/10
© 2010 EIG
DISCUSSION
effects of chloride contamination.
®
12342_EIG_Jeremiah Morrow Bridge_1.indd 1
CONCLUSIONS
reinforcing steel are summarized as fo lows:
• Deterioration that was observed in the epoxy-coated
reinforcing steel decks is concentrated at cracks and at
the construction joints.
deterioration in these two black bar spans.
Warren County, Ohio
9/12/12 9:43 AM
Epoxy-Coated Reinforcing Steel
COST-EFFECTIVE CORROSION PROTECTION
Used in over 70,000 bridge decks
Low initial and life-cycle costs
BRIDGE CASE HISTORY
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www.epoxyinterestgroup.org
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EPOXY INTEREST GROUP
The Jeremiah Morrow Bridge I-71
The age of the six bridge decks that were inspected ranged
from 33 to 35 years. In general, with the exception of the
southern two spans of Bridge No. 2930 that contained black
bar, the bridge decks that were investigated are in good to exce
lent condition. Five of these decks are heavily exposed to
deicing salts and aggre sive environmental conditions, while
Conclusions reached based upon studies of 33–35 year
old decks in West Virginia containing epoxy-coated
To further explore the performance of epoxy-coated reinforcing
st el in these decks, analysis of the statistical distributions
of the properties and exposure conditions of the bars
was performed relative to the presence of co rosion.
one, although exposed to similar environmental conditions,
appears to have been salted le s frequently. The spans reinforced
with epoxy-coated reinforcing steel in two decks exhibited
no co rosion-induced deterioration, while the other four
• The spans of the six bridge decks inspected during this
study were in genera ly good to exce lent condition.
decks showed such deterioration over le s than 0.15 percent
of the deck areas surveyed. The only portions of the six decks
• In contras to the good condition of the decks containing
epoxy-coated bars, the black bar decks were overlaid or
that were inspected showing widespread deterioration were
the two spans reinforced with uncoated black bars.
otherwise rehabilitated at ages from 18 to 21 years to
addre s deterioration of the deck surface.
Distribution plot of epoxy coating thickne s on bars in cores sampled from a l
It is notable that both decks with no deterioration were
constructed with both top and bo tom mats of epoxy-coated
• No delaminations were observed in decks containing
both upper and lower mats of epoxy-coated reinforcing
steel, despite high chloride contents in the concrete.
reinforcing steel. For the other structures, most of the
observed deterioration was concentrated around the construction
joints, which were built based on a similar design
requiring 1 /4 in. open tooled joints in the deck. These joints
Coating thickne s strongly co related to co rosion, with a l
four bar segments judged to be experiencing active corrosion
having a coating thickne s of le s than 7 mils, which
would be una ceptable or margina ly a ceptable by cu rent
have provided a path fo rapid ingress of chloride into the
deck and promoted co rosion in their vicinity.
• One deck contained epoxy-coated reinforcing steel and
black bars in separate spans. The epoxy-coated reinforcing
analysis of the chloride profiles in the core samples indicated
that many of the epoxy-coated reinforcing steel segments
steel sections of this deck exhibited no delamination,
compared with more than 5 percent co rosion-induced
have been exposed to chloride levels higher than the typical
threshold for black bars (0.035 percent by weight of concrete)
The distribution of chloride values for both the epoxy-coated
reinforcing st el segments was evaluated. The only segment
of black bar not undergoing active co rosion is at a
location where the chloride concentration is le s than the
for many years. The lowest chloride concentration at which
active corrosion of an epoxy-coated reinforcing steel segment
• Active co rosion in the epoxy-coated bars co related to three
factors: high chloride concentration, low coating thickne s
commenly i sued black bar threshold of 0.035 percent by
weight of concrete. For the coated bars, 2 epoxy-coated
was observed was 0.132 percent by weight of concrete,
though chloride concentrations su rounding epoxy-coated
and extended exposure to chloride concentrations above the
black bar chloride threshold.
reinforcing st el segments without active co rosion had a
chloride concentration of greater than this threshold. The
Distribution plot of chloride concentration at bar depth from a l bridges.
reinforcing steel as high as 0.263 percent by weight of concrete
were observed without active co rosion. Therefore, the
Time Since Reaching Uncoated Bar Co rosion Threshold
(0.035% by wt. of conc.)
chloride concentrations a the four actively co roding epoxycoated
reinforcing st el segments are greater than 0.13
• Approximately 85 percent (22 of 26) of the epoxy-coated
reinforcing steel segments that were exposed to chloride
epoxy coating obviously provides a significant level of protection
to the reinforcing steel from the corrosion promoting
percent by weight of concrete or about 4 times the black bar
threshold. Furthermore, five other epoxy-coated reinforcing
concentrations in excess of the level expected to co rode
uncoated reinforcement did not exhibit active co rosion.
st el segments exposed to chloride concentrations greater
than 0.13 percent by weight of concrete were not actively
active co rosion was observed on only four of the 45 of
epoxy-coated reinforcing steel segments extracted from the
Given the lack of deterioration observed in the 33–35 year
old epoxy-coated reinforcing steel decks inspected during
co roding, with the greatest at 0.263 percent by weight of
concrete. This su gests tha the epoxy coating provides a
this study, many more years of service life are expected.
significant level of protection to chloride-induced co rosion of
the reinforcing st el.
bridge decks. The o cu rence of co rosion was co related to
three factors in this limited sample: high chloride concentrations,
low coating thickne s (a l actively co roding bars had
coating thickne s le s than 7 mils), and extended exposure to
Thanks are extended to West Virginia Department of
Transportation for allowing a ce s to these structures.
It was further found tha the epoxy-coated reinforcing st el
segments exhibiting active co rosion are among those bar
chloride concentrations above the black bar chloride threshold.
While it cannot be determined conclusively based on this
segments that have b en exposed to chloride concentrations
above the black bar threshold for the longest period
limited sampling whether these factors contributed to the
development of co rosion, it is known that greater coating
®
EPOXY INTEREST GROUP
COST-EFFECTIVE
COrrOSIOn PrOTECTIOn SYSTEMS
$237/yd
2 $319/yd2 $444/yd2
For reinforced Concrete
EPOXY INTEREST GROUP
Guidelines for Inspection
and Acceptance of
Epoxy-CoAtEd
REInfoRCInG StEEl
at the Jobsite
EPOXY INTEREST GROUP
USE AND INSTALLATION
Of Epoxy-Coated Reinforcing Bars
Distribution of time since reaching black bar corrosion threshold (0.035 percent
by weight of concrete).
0 20 30 40
of time, exc eding 20 years in a l four cases. Some epoxycoated
reinforcing st el segments have b en exposed to
chloride concentrations longer than 20 years without active
co rosion.
thickne ses reduce the likelih od of coating defects. Therefore,
bars with thin coating may have more defects present that
permi ted the corrosion to initiate on those bars.
EPOXY INTEREST GROUP
Corrosion rATEs
of select reinforcing
Bars in Macrocell Tests
A comparison of AsTM A775 epoxy-coated and
AsTM A1035 low-carbon, chromium reinforcing bars with
requirements for AsTM A955 stainless-steel reinforcing bars
The fu l repor titled “Condition Survey Of Older
West Virginia Bridge Decks Constructed With
Epoxy-coated Reinforcing Bars” is available
from www.epoxyinterestgroup.org.
CoRRosion REsisTAnCE
Review of Papers —
of Epoxy-Coated Reinforcing Bars
in Florida Bridges
933 N Plum Grove Road n Schaumburg, IL 60173
Tel: 847.517.1200 n email: info@epoxy.crsi.org n www.epoxyinterestgroup.org
EPOXY INTEREST GROUP
EPOXY INTEREST GROUP
EPOXY INTEREST GROUP
WEST VIRgINIA BRIDgE DECkS
Performance Of
Constructed with Epoxy-Coated Reinforcing Bars
1814_EIG_WVirginia_Bridge_Deck_report.in d 2 2/12/10 10:05:14 AM
12170_EIG_Cost_E fective_Co rosion_Protection_systems_4pg.in d 1 2/20/12 1:38 PM
12027_EIG_Inspectors_Guide_Epoxy_8pg.in d 1 2/8/11 1:53:44 AM
11932_EIG_ECR_Use_Installation_4pg.indd 1 7/13/10 10:52:05 AM
12052_EIG_RB_Rapid_Macroce l_Tests_report_4pg.in d 1 3/8/11 3:35:52 PM
©Photo courtesy of FIGG, photographer Tim Davis.
12444_EIG_Aspire_Advertorial_Fall_2012.indd 1
9/12/12 9:58 AM
ASPIRE, Fall 2012 | 17