Field Investigation of Corrosion-Protection Performance of Bridge Decks Constructed with Epoxy-Coated Reinforcing Steel in Virginia

Abstract

The corrosion-protection performance of epoxy-coated reinforcing steel (ECR) in three 17-year-old bridge decks in Virginia was assessed. The decks had an upper mat of ECR and a lower mat of bare steel. Surface cracking in the right traffic lane was visually surveyed and 12 cores randomly located in the lowest 12th percentile cover depth in each deck were drilled. The concrete core and the extract ECR were visually inspected. In the concrete moisture content, absorption, percent saturation, carbonation depth, and the effective chloride diffusion constant were measured. In the ECR physical damage, coating thickness, adhesion loss and corrosion at damaged sites, and undercoating corrosion at adhesion test sites were measured. The chloride content of the concrete and carbonation of the ECR trace were determined. Significant coating adhesion loss occurred before the chloride arrived at the bar depth. The debonding of the epoxy is wet debonding, which is predicted by the negative thermodynamic work of adhesion. ECR will extend the service life of only 5 percent of the bridge decks in Virginia. Thus, its use is not cost-effective. Additional decks should be evaluated to confirm the results of this and other studies.