United States Department of Transportation
i
Time-to-Corrosion of Reinforcing Steel in Concrete Slabs. Volume 5: Calcium Nitrite Admixture or Epoxy Coated Reinforcing Bars as Corrosion Protection Systems
-
1983-09-01
[PDF-3.71 MB]
Details:
-
Creators:
-
Corporate Creators:
-
Contributors:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Right Statement:
-
Geographical Coverage:
-
Edition:Interim
-
Corporate Publisher:
-
Abstract:Thirty-one relatively large reinforced concrete slabs were fabricated in 1980 using either non-specification epoxy-coated reinforcing steel or calcium nitrite admixture with black (uncoated) steel. Their performance is compared with uncoated steel in concrete without admixtures. The slabs were placed in two lifts: the bottom lift consisted of a bottom mat of reinforcing steel in chloride-free concrete; and a top lift consisting of the top-mat rebars in concrete contaminated with various quantities of sodium chloride. All the electrical connections between the reinforcing mats were made exterior to the slabs so that the corrosion current flow could be monitored. A worst case type of research design was used by specifying poor quality concrete, nonspecification epoxy-coated rebars, and good electrical coupling between the rebar mats. After curing, the slabs were mounted above ground and exposed to the environment of the Washington, D.C. location. They were periodically subjected to additional chloride exposure while being monitored for about 1 year to determine the corrosion rate. Selected slabs were than demolished to confirm the findings of the nondestructive testing. Findings of the study indicate that both epoxy-coated reinforcing steel and calcium nitrite can provide more than an order of magnitude reduction in the corrosion rate; and thus should provide long-term protection against corrosion-induced damage on properly engineered and constructed structures in severe salt environments. Some of the variables which affected the performance of the slabs were the chloride content in the calcium nitrite experiment, and the selective coating of the upper mat only, versus the coating of both mats in the coated rebar experiment.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
