Finite element modeling of concrete cover crack propagation due to non-uniform corrosion of reinforcement

Non-uniform corrosion of reinforcement causes concrete cracking in chloride contaminated RC structures. Due to an interaction existed between the concrete cover cracking and the ingress of aggressive agents in chloride environments, chloride ingress is significantly enhanced by cracks. Thus the investigation on the cracking paths and cracking propagation process resulting from steel corrosion is very essential. This work proposed a numerical model to study the cracking of cover concrete. The physical model was focused on the middle-located rebar corrosion, and the effect of the neighboring longitudinal reinforcing bars on the cracking of cover concrete was mainly considered. A damaged plasticity model for the study on the failure behavior of concrete cover was built. The non-uniform radial displacement distribution was adopted to simulate the corrosion expansion behavior of the rebar. The cracking propagation process of cover concrete with two neighboring longitudinal reinforcing bars embedded was simulated and monitored with the level of corrosion build-up. The present approach was verified by the available experimental observations. The influences of concrete cover thickness, rebar diameter and rebar spacing on the failure patterns of concrete cover and crack width propagation were examined. And limiting criteria for the cracking modes were established.