Multi-physics coupling model of chloride-induced rebar corrosion and concrete cracking in reinforced concrete structure

Chloride-induced rebar corrosion and concrete cracking are complex processes driven by interacting multi-physics mechanisms and multiple contributing factors. This study proposes an innovative multi-physics modeling framework to comprehensively analyze the entire degradation process, from ionic transport to corrosion initiation and cracking induced by corrosion expansion. A multi-ionic transport model is developed to quantify the impact of electrochemical processes and crack propagation on ionic transport. Based on phase-field theory and corrosion kinetics, a corrosion model is then proposed to describe corrosion product loss, filling, and accumulation. A multiphase phase-field cracking model is hence developed to characterize fracture behavior and degradation induced by corrosion product pressure. Third-party data are used to validate the proposed models and framework. Results indicate ignoring multi-ion interactions overestimates pore-solution chloride, while neglecting electromigration distorts local ion distributions. Explicit crack representation generates preferential transport pathways, accelerates ingress, and increases peak current density and electrochemical potential by over 10%. Coupling the displacement field enhances crack-growth predictions and avoids premature or excessive cracking. This work offers a new perspective on cracking and durability deterioration in reinforced concrete by establishing a mechanistic framework that enables more reliable predictions in the cracked state, thereby reducing reliance on empirical formulations.