A multi-phase multi-species phase field model for non-uniform corrosion and chloride removal in concrete

Electrochemical chloride removal (ECR) facilitates the retardation of rebar corrosion and the extension of service life. In this paper, we present a multi-phase multi-species phase field model at the mesoscale to investigate the time-dependent processes of rebar corrosion, electrochemical chloride removal, and re-corrosion. This model captures multi-species ion transport, electrochemical reactions, electrochemical chloride removal, concrete cracking and crack-induced diffusivity variation in the processes of rebar corrosion. This model was verified using two experiments from the literature. Parametric studies were conducted to observe the effects of current density, treatment time and concrete cover thickness on chloride concentration and crack width during the corrosion initiation and corrosion propagation stages. The chloride transport and crack evolution processes in ECR-treated concrete were highlighted. Two indexes are proposed for the chloride-induced corrosion resistance of concrete in the corrosion initiation and corrosion propagation stages.