Influence of Microdefect Size on Corrosion Behavior of Epoxy-Coated Rebar for Application in Seawater-Mixed Concrete

Corrosion behavior of epoxy-coated rebar with different size microdefects in uncarbonated/carbonated simulated pore solution (U/CSPS) seawater concrete was investigated. Specimens both solutions underwent two stages corrosion, according to the electrochemical impedance spectroscopy (EIS) response. The initial stage extension corrosion. second dominated by diffusion process, due corrosion products blocking defects and hindering transportation reaction matter. Local (LEIS), scanning vibrating electrode technique (SVET) measurements observation indicated that 50 μm might be threshold, because specimens bigger than diameter significantly more severe. Crevice identified occur experiments. USPS CSPS were mainly Fe3O4 FeOOH, respectively. α-FeOOH β-FeOOH exhibited an anion ion-selective property which induced crevice CSPS. In particular, it is contended herein has cation protect substrate USPS.