The corrosion protection performance of epoxy-coated reinforcing steel (ECR) was evaluated in 18 concrete bridge decks in Virginia in 1997. The decks were 2 to 20 years old at the time of the investigation. The concrete bridge deck inspections included crack survey and cover depth determination in the right traffic lane. Maximum of 12 cores with the top reinforcement randomly located in the lowest 12th percentile cover depth and 3 cores with the truss bars were drilled from each bridge deck. The concrete core evaluation included visual examination and determination of carbonation depth, moisture content, absorption, percent saturation and chloride content at 13 mm depth. Rapid chloride permeability test was also performed for the surface and base concrete on samples obtained from cores containing truss bars. The ECR inspection consisted of visual examination and damage evaluation, coating thickness and adhesion determination. The condition of the steel underneath the epoxy coating was also evaluated. Adhesion loss of the epoxy coating to the steel surface was detected for 4 years old bridge decks. The epoxy coating had debonded from the reinforcing bar before the chloride arrival. Visible signs of a possibility of a corrosion process underneath the coating suggest that ECR will not provide any or little additional service life for concrete bridge decks in comparison to black steel. Other systems, which will provide longer protection with a higher degree of reliability against chloride induced corrosion of steel in concrete, should be considered. / Ph. D.

Corrosion of reinforcing steel in concrete is a significant problem around the world. In the United States, there are approximately 600,000 bridges. From those bridges 24% are considered structurally deficient or functionally obsolete based on the latest, December 2010, statistic from the Federal Highway Administration (FHWA). Mainly, this is due to chloride attack present in deicing salts which causes the reinforcing steel to corrode. Different solutions have been developed and used in practice to delay and prevent corrosion initiation. The purpose of this research is to investigate the influence of corrosion on the failure mechanism that occurred on an Interstate 81 bridge deck. After 17 years in service, a 3ft x3ft closure pour section punched through. It was part of the left wheel path of the south bound right lane of the bridge deck. The bridge deck was replaced in 1992 as part of a bridge rehabilitation project, epoxy coated reinforcement were used as the reinforcing steel. Four slabs from the bridge deck, containing the closure, were removed and transported to the Virginia Tech Structures and Materials Research Laboratory for further evaluation. Also, three lab cast slabs were fabricated as part of the assessment program. Corrosion evaluation and concrete shrinkage characterization were conducted in this research. The corrosion evaluation study included visual observation, clear concrete cover depth, concrete resistivity using single point resistivity, half-cell potential, and linear polarization using the 3LP device. Shrinkage characteristics were conducted on the lab cast slabs only, which consisted of monitoring shrinkage behavior of the specimens for 180 days and comparison of the data with five different shrinkage models. Based on the research results, guidance for assessment of other bridge decks with similar conditions will be constructed to avoid similar types of failures in the future. / Master of Science