Anti-Corrosion Performance of Migratory Corrosion Inhibitors on Reinforced Concrete Exposed to Varying Degrees of Chloride Erosion

This study investigated the anti-corrosion performance of commercial amino alcohol migratory corrosion inhibitors (MCIs) on concrete that underwent varying degrees of chloride erosion. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PD), scanning electron microscopy, and energy dispersive spectroscopy (SEM-EDS) analyses were performed to study the anti-corrosion performance and mechanism of the MCIs on the steel bars. The results indicated that the corrosion resistance of the steel bars in concrete was significantly improved by coating with the MCIs, and the earlier the specimens were coated with the MCIs, the higher the anti-corrosion efficiency. The anti-corrosion efficiency was 55.35% when the MCIs coating was applied before chloride erosion; however, the anti-corrosion efficiency decreased to 3.40% when the MCIs coating was applied after the ninth drying–wetting cycle. The improvement in corrosion resistance of the steel bar in concrete coated with MCIs was due to the protective MCIs-molecule film that formed on the steel bar surfaces, and the oxidative dissolution of iron at the anode was effectively inhibited by the MCIs coating.