CONDITION AND PERFORMANCE OF EPOXY-COATED REBARS IN BRIDGE DECKS

The Federal Highway Administration and partners provided funding for a joint research project to evaluate in-service bridge decks in Pennsylvania and New York constructed with epoxy-coated reinforcing steel. This study examines the long-term performance of epoxy-coated reinforcing steel in concrete bridges and structures exposed to salt. The sampling plan was designed to detect progressive corrosion, even if the frequency of occurrence was less than 3% of the global population. Results showed that the frequency of occurrence of progressive corrosion is less than 3% in Pennsylvania and at least 3% in New York. A total of 409 rebars showed no evidence of corrosion; 62 bars had a number of small, countable corrosion spots; and only two rebars, both in New York, exhibited significant visible corrosion. Coating adhesion reduction or loss was found to be more prevalent and extensive. Only 47% of the bars tested had no reduction in adhesion. No correlation was found with corrosion-condition rating and chloride exposure time or chloride content. Among all the variables included in the analyses, logarithm of electrochemical impedance spectroscopy, number of holidays, and number of bare spots were found to be the best predictors of corrosion-condition rating, but in all cases the correlations were weak. Corrosion-condition rating did not correlate with coating thickness, clear concrete cover, color of epoxy, or bridge deck-condition rating. A good correlation between concrete resistivity and coulombs passed was found.