Correction of chloride threshold concentration and time-to-corrosion due to reinforcement presence

摘要

Reinforcement presence affecting corrosion threshold concentration, C_t, determination and time-to-corrosion, T_i, has been investigated. Elevated Ct and decreased T_i due to reinforcement physical obstruction on the path of chloride ingression into concrete has been examined with finite element modeling. Results indicated that reinforcement with larger size, better corrosion resistance, less cover thickness, or a more flat leading edge causes more pronounced T_i reduction. Experimental results exposed aggregate content discrepancy within reinforced bar vicinity zone. According to this finding, a multi-shell chloride diffusion model, in which specific chloride ion diffusivity in each shell surrounding bar presents, is proposed. The Ct results of proposed model are discussed along with those acquired from traditional one-dimensional model, in which chloride diffusion follows Fick's second law without considering reinforcement presence, and two-dimensional model with the effect of reinforcement physical obstruction regarded.