Numerical simulation of rust growth and corrosion-induced cracking in reinforced concrete samples

Corrosion-induced cracking is a leading cause of durability loss in reinforced concrete structures exposed to chloride environments. Existing numerical models often assume uniform rust expansion or treat chloride diffusion and mechanical cracking as sequential processes, limiting their ability to capture spatially heterogeneous corrosion patterns. This work presents a finite element framework that couples chloride transport with mechanical model describing cracks together with concentration triggered rust expansion and crack-enhanced diffusion. Using the thermal analogy in Abaqus with user subroutines, the approach enables non-uniform corrosion to develop naturally in response to local chloride concentration. A smooth activation function captures the progressive filling of the porous zone before expansive pressure develops. The framework implements bidirectional coupling where mechanical cracking accelerates chloride ingress through crack width dependent diffusion, creating a self-accelerating deterioration process. The model was validated against experimental results from accelerated corrosion tests, successfully reproducing both non-uniform rust distribution and characteristic crack patterns. While the formulation assumes two-dimensional sections and neglects electrochemical kinetics, satisfactory agreement with experiments demonstrates that essential features of chloride-induced deterioration can be captured using this simplified approach.