On the effect of simulated contamination of chlorides and sulfates on steel rebar corrosion: Electrochemical behavior and surface analysis

Abstract

To understand the effect of sulfate ions on the chloride-induced corrosion of reinforced concrete, this study focuses on the electrochemical behavior and surface analysis of standarded carbon steel that was exposed to simulated pore solutions, with different combinations of high and low chloride and sulfate concentrations. Linear scanning voltammetry and electrochemical impedance spectroscopy were used to monitor the corrosion reaction. Steel surface was characterized by X-ray photoelectron spectroscopy and field emission scanning electron mi-croscopy. Results indicate that the presence of sulfate affects the electrochemical behavior of steel corrosion at a low and high chloride concentration, where the capability of the corrosion protective layer was influenced by the increase of the sulfate and chloride content. Calcium carbonate deposits were observed at the surface of corroded samples, where higher precipitation of calcium carbonate crystals on carbon steel surface is associated with higher rates of localized corrosion.