Numerical Simulation of Chloride-Induced Corrosion Initiation in Reinforced Concrete Structures with Cracks

Steel corrosion is a major problem with concrete structures. For cracked concrete structures exposed to chloride environment, chloride diffusivity through the crack (Dcr) is higher than that through the concrete matrix (Do), and therefore, the corrosion will occur at an earlier time. In this study, finite-element analysis is performed to study the process of chloride diffusion through cracks. For various values of Do, Dcr, and crack width, the chloride-concentration distribution is determined. Based on the simulation results, the empirical equation for an equivalent diffusion coefficient (Deq) will be derived, which can be used directly in the solution of the one-dimensional diffusion equation to calculate the predicted chloride profile, the corrosion-initiation time, and penetration of corrosion front. The study will provide a convenient but accurate approach for predicting the chloride diffusion, including the corrosion initiation, under real-world situations where cracks are present in a concrete structure.