Multiphysics and multiphase mesoscopic study on electrochemical corrosion of reinforcement caused by chloride salt

Reinforcement corrosion caused by chloride attack is one of the main reasons for the degradation of reinforced concrete (RC) structures, especially those exposed to marine environment. To study the effect of chloride attack on the electrochemical corrosion behavior of reinforcement, a 2D meso-numerical model coupling ion transport and electrochemical corrosion was established by modifying the anode Tafel slope in this paper. More importantly, gaussian function model with clear physical meaning is proposed to describe the distribution of reinforcement corrosion layer. The reliability of the proposed model is further verified by compared with the third-party experiments data. Furthermore, the effects of electric field effect, meso-structure, maximum corrosion depth and corrosion rate on the distribution of reinforcement corrosion layer are investigated based on the proposed model. The numerical simulation results show that the influence of electric field effect and interfacial transition zone (ITZ) on corrosion morphology cannot be ignored. Moreover, the novel gaussian distribution model with physically meaningful parameters has wide applicability through comparison with experiments. Specially, a simulation of chloride diffusion trajectories in concrete meso-structures reveals how ITZ promotes chloride diffusion. The research of this paper provides theoretical support for the rust expansion cracking and service life prediction of reinforced concrete structures. [Display omitted] •A multiphysics numerical model is proposed to fully explore the mechanism of electrochemical corrosion of reinforcement.•Gaussian function model with clear physical meaning is proposed to describe the distribution of corrosion layer.•The mechanism of corrosion potential promoting non-uniform corrosion of reinforcement is revealed by numerical simulation.