Service life prediction of concrete structures subjected to chloride attack by numerical simulation

An integrated numerical simulation method for time-dependent performance change of reinforced concrete structures subjected to chloride attack is presented. The computational system is composed of several mathematical models relating to deterioration process of structure; transport of aggressive materials within concrete cover, corrosion of reinforcing steel bars embedded in concrete, and mechanical behaviour of concrete member with corroded reinforcing bars. The performance of RC structure with assumed material properties and structural dimension under given environmental condition is numerically simulated as a function of service time. To demonstrate the effectiveness of the proposed method as a verification tool for lifecycle management of structures, service life of RC bridges is numerically simulated in this paper, Repair and rehabilitation techniques by chloride removal and externally bonded continuous fiber sheet are considered in the simulation. Since it is based on detailed modelling of degradation phenomena of concrete structure, the proposed system can naturally express the effects of these repair and rehabilitation techniques on service life extension of structures. It is analytically shown that continuous fiber sheet can extend service life of structures by reducing of chloride ingress into concrete as well as by carrying tensile stress as an external reinforcement.