Corrosion initiation time of steel reinforcement in a chloride environment—A one dimensional solution

Abstract

A mathematical model is presented for the chloride induced corrosion of reinforcing steel bars (rebars) in concrete. The time for the chloride concentration level to exceed the threshold limit to initiate corrosion on the rebars was calculated using first principles. The model is characterized by the time dependent surface concentration due to adsorption at the surface of the concrete. Although the entire adsorption and diffusion process is complicated, the predictions of the model are consistent with experimental results. The simplifying assumption of a constant diffusion coefficient does not affect the model predictions. A finite difference model was used to study the effect of water and oxygen on chloride diffusivity in concrete.