Coating Condition Evaluation of Epoxy Coated Rebar

The initial results of ongoing research on the corrosion condition of epoxy coated steel reinforcement (ECR) from a low permeability concrete marine structure with thin preexisting structural cracks after ~20 years of service are presented. Coating autopsies and electrochemical impedance spectroscopy measurements were conducted on ECR samples extracted from the field. No preferential coating deterioration was observed on ECR zones intersected by a crack compared to the rest of the ECR segment. Results from EIS measurements show a high frequency (hf) loop in disbonded ECR samples. Larger hf loops in cracked concrete samples are indicative of larger electrolyte conductance. The low frequency impedance response behavior is characteristic of current and interfacial capacitance distribution in a transmission line configuration. Further tests are in progress.