Corrosion behavior analysis of steel in simulated carbonated concrete pore solution based on 3D optical microscopy method

Abstract

The main purpose of this study was to analyze the corrosion behavior of steel in simulated carbonated concrete pore solution (SCCPS) with the help of 3D optical microscopy method. This method was adopted to provide qualitative observation of surface with 3D information and quantitative results of defects for steel which was affected by various NaCl contents and inhibitors (inorganic inhibitor (NaNO2) and organic inhibitor (DEA(C4H11NO2)). As the NaCl contents changed during all corrosion periods, the mean pitting depths (Ra) and NaCl contents showed stronger linear relationships, and the slop values presented as the Ra added value of per wt% for different inhibitor systems were all detected to be closed to 3 μm/wt% in all linear regression models. This method provided a new angle to investigate and estimate the defect variation on steel surface, which denoted to better understand the corrosion behavior in SCCPS. Additionally, electrochemical impedance spectroscopy (EIS) and weight loss measurements were also used to verify the results of 3D optical microscopy analysis.