Corrosion-fatigue degradation in reinforced concrete structures: A multiphysics phase-field modeling approach

Corrosion-fatigue interaction is a complex and strongly coupled chemo-mechanical degradation process that critically impacts the durability of reinforced concrete (RC) structures exposed to aggressive environments and cyclic loading. This work presents a holistic multiphysics phase-field modeling framework for simulating the full spectrum of coupled physical mechanisms that govern corrosion-fatigue degradation in RC structures. The proposed framework captures: (i) chloride transport and binding in the concrete matrix leading to corrosion initiation, (ii) reactive transport and precipitation of Fe 2 + and Fe 3 + ions in concrete pores, (iii) pressure accumulation due to rust formation and precipitation around steel reinforcement, (iv) corrosion diffusion and material degradation in steel representing softening due to film rupture and material dissolution, (v) fatigue degradation in steel reinforcement, (vi) fatigue crack propagation in concrete as well as splitting fracture due to corrosion, and (vii) degradation-dependent diffusivity enabling interaction between mechanical cracking and ionic transport. These processes are fully coupled within a unified chemo-mechanical phase-field formulation. Key components of the corrosion and fatigue submodels are validated against experimental data to ensure physical fidelity. The framework is then used to investigate the bidirectional interaction between corrosion and fatigue in both 2D and 3D settings, demonstrating how corrosion accelerates fatigue failure and, conversely, how early-stage fatigue cracking promotes corrosion progression. This comprehensive approach offers a robust tool for assessing service life and designing more durable RC structures under coupled environmental and mechanical loading. The corresponding source codes are openly available at [ https://doi.org/10.25835/3duuzvj4 ], allowing reproducibility by interested researchers.