Epoxy-coated reinforcing steel (ECR) with nine kinds of coater/powder/steel/size combinations were evaluated based on their performance in resisting corrosion. Specimens prepared from these bars were characterized with regard to their coating thicknesses and surface conditions before being immersed in sodium chloride solution. Subsequently, electrochemical impedance spectroscopy (EIS) scans and polarization resistance measurements were performed periodically during approximately 200 days of exposure. In the case of EIS, coating degradation could be detected at a very early stage; and a great variation in the performance between ECR of different coater/powder/steel/size combinations was observed. The specimens were ranked based on their impedance responses and an attempt was made to correlate the ECR’S performance with their coating characteristics.
Key Words: corrosion, reinforcing steel, epoxy, coating, electrochemical impedance spectroscopy, and polarization resistance