Finite element simulation of mechanical-electrochemical coupling effects of steel corrosion in ecc structures

Corrosion of steel reinforcement due to rapid ingress of chlorides or moisture may be accelerated when cracks occur in concrete structure. Additionally, steel reinforcement in concrete structures is often in complex stress and strain conditions, which affects the corrosion response of the embedded reinforcement. This research reports the coupled mechanical-electrochemical effects of steel corrosion in reinforced concrete structures using Multiphysics coupling techniques. Macrocell and microcell corrosion were integrated into the numerical models. The finite element models take into account the change of transport properties of oxygen and conductivity of concrete under various moisture content levels. The modelling results (i.e., current density) show that cracking of concrete cover can accelerate the diffusion process. Nevertheless, the propagation of corrosion was limited in severely damaged beams compared to mild damaged ones due to the more uniform corroding area of the reinforcement. Results also show that the rebar's high level of strain and stress accelerated the corrosion process significantly at low saturation levels. However, the strain and stress state of the reinforcement is negligible at high saturation levels due to the limitation of oxygen transport to the steel concrete interface. These models are being expanded to examine the use of more non-conventional concrete materials in improving the corrosion performance of reinforced concrete structures.