Modeling the interaction between non-uniform corrosion of rebar and corrosion-induced cover cracking

Circumferential non-uniform corrosion of rebars in concrete normally occurs in marine environment, and has an adverse impact on corrosion-induced cover cracking which may conversely change the circumferential corrosion profile. This paper investigates the interaction between chloride-induced non-uniform corrosion and corrosion-induced cover cracking. A chloride penetration model is introduced to predict the distribution of chloride content in concrete, which can determine the corrosion initiation time around the circumferential surface of a rebar. Subsequently, the time-dependent corrosion rate around the rebar surface can be calculated based on electrochemical theory, and then the corrosion profile at different time can be deduced. With the cross-sectional corrosion profile as an input, a mechanical model for corrosion-induced cover cracking can be utilized to simulate the development of surface crack, which has a significant influence on the diffusion of chloride ions and oxygen and may change the corrosion process. The derived model is verified with experimental results, and then a case study is conducted to demonstrate the time-varying non-uniform corrosion profile. Numerical simulation results indicate that, compared with uniform corrosion, non-uniform corrosion can lead to earlier cover cracking and faster development of surface crack width.