Abstract: In the present paper, a complex model for predicting chloride penetration into concrete structure under coupled heat and moisture transport processes is developed. Also the decay of concrete’s durability is taken into account by introducing a scalar damage index into the model. The durability decay is caused by environmental loadings including accelerating moisture and chloride ingress in concrete. The governing equations for the transport of heat, moisture and chlorides into concrete are derived practically and solved numerically by finite element analysis in space and time domains. Comparisons with analytical tests are carried out to show the reliability and the effectiveness of the proposed numerical model. Further numerical simulations are also carried out to study influences of various factors (such as convection, decay of durability, and binding isotherm) on the initiation time of reinforcement corrosion in concrete.