Service life of reinforced concrete structures with corrosion damage due to chloride attack

It is well known that the chloride in concrete can result in rebar corrosion. Due to the expansive nature of rust, rebar corrosion deteriorates the reinforced concrete structures by creating damages in the concrete around the rebar such as cracking and spalling, which affect the durability and service of life of reinforced concrete structures. This study presents a comprehensive model for predicting service life of reinforced concrete structures exposed to chloride attack. The model characterizes various stages in the process of corrosion damage: the initiation of corrosion, the initiation of cracks and critical size of cracks. The initiation process is modeled by coupled chloride and moisture diffusion equations. The initiation of cracks and critical crack length are determined by coupling the corrosion rate, the permeation of corrosion product and mechanical restraint of surrounding concrete. Until the initiation of cracks, the mechanical problem is solved by using elastic theory for thick wall cylinder. After the cracking, the theory of thick wall cylinder is combined with nonlinear fracture mechanics. The period of each deterioration stage can be determined using the present model.