Simulation of time-varying corrosion rate of rebars and corrosion-induced cracks in reinforced concrete structures subjected to chloride contamination

Abstract

Corrosion of rebars and consequent corrosion-induced cracks significantly deteriorate durability and serviceability of reinforced concrete (RC) structures. This paper presents a time-dependent numerical model to simulate the entire corrosion process from initiation stage to crack propagation stage and consider the effect of cracks on the development of corrosion current density. Chloride transport model was implemented to determine evolution of corroded area in cross-section of rebars, while two configurations of corroded length along the bar axis was considered: (1) the entire length of rebar was simultaneously corroded and (2) the corroded length evolved gradually from the middle of the bar towards its two ends. Corrosion current density was calculated based on microcell and macrocell electrochemical mechanisms, while a mechanical model was established to simulate corrosion-induced concrete cracking. The results showed that the proposed numerical model was capable of predicting natural corrosion process and consequent crack propagation in RC structures subjected to chloride attack. When cracks developed through the concrete cover, corroded area spread faster, microcell and macrocell current densities increased, and the rust layer became more rounded.