Numerical simulation of steel corrosion in chloride contaminated concrete

Abstract

Corrosion is one of the main reasons for the degradation of reinforced concrete structures, especially of those exposed to a chloride-contaminated environment. To study the effect of chloride ions on the corrosion of steel embedded in concrete, two electrochemical parameters, namely, the anodic Tafel slope and potential, were theoretically analyzed and semi-empirically modified by the concentration of chloride ions in concrete. Subsequently, a numerical model that couples the mass transport and electrochemical corrosion process was established to simulate the transport of chloride ions and the evolution of steel corrosion that occurred simultaneously in the concrete. Based on the proposed numerical model that incorporated the appropriate electrochemical parameters, the corrosion current density and corrosion potential were obtained numerically and they coincided well with the experimental data. Finally, the proposed model was applied to study the chloride ion distribution as well as the corrosion current density around the cross-section and circumference of the steel bar in concrete members with single or multiple steel bars. The results indicate that the proposed numerical modelling method can be used to predict the corrosion-initiation time, as well as the development of the morphology of the corrosion profile of steel bars in concrete structures.