Phase Field Modeling Considering Interfacial Effect for Investigating Corrosion‐Induced Damage in Confined Realistic Multiphase Structures

Rebar corrosion is one of the primary causes of deterioration and reduction in the resistance of reinforced concrete (RC) structures. Previous studies employing phase field modeling for corrosion‐related problems commonly idealize concrete as a brittle, homogeneous material and unconfined structures. Moreover, the phase field methods adopted in these studies do not satisfy the strain‐tensor orthogonal condition, which has been demonstrated to be essential for accurately modeling the damage in brittle or quasi‐brittle materials. To address these research gaps, the present paper provides the following main contributions: (i) a phase field method with interfacial effect, which satisfies the strain tensor orthogonal condition, is employed; (ii) the influences of the distribution and number of inclusions or/and pores, as well as the concrete cover thickness, on damage evolution in both unconfined structure and confined structure are investigated; and (iii) damage in realistic RC structures with randomly distribution and shape of aggregates induced by corrosion expansion of two rebars is numerically simulated. The results illustrate crack propagation paths and corrosion‐induced rust expansion displacement values at both the crack initiation state and the fully cracked propagation state of the structure. Through the representative numerical examples, an overall insight into corrosion behavior in typical multiphase structures is provided. The obtained results contribute to rational rebar layout and strengthening strategies for practical RC structures, thereby mitigating the rapid failure of structures caused by rebar corrosion.