Probabilistic analysis of corrosion initiation in existing reinforced concrete structures with imprecise random field

Abstract

Reasonable assessment of corrosion initiation probability in existing reinforced concrete structures is an important premise for ensuring the safety and durability of such structures. In this paper, a simplified dual time-dependent chloride diffusion model considering the load effect is established and verified by comparing its results with the experimental data. Then, a modelling method of imprecise random fields is developed. In addition, a novel probabilistic analysis method of corrosion initiation in existing RC structures with imprecise random fields is proposed. The case analysis results show that the corrosion resistance of existing structures will be overestimated without considering the effect of imprecise random fields. In comparison, the upper bound of cumulative probability of corrosion initiation is 2.29 times of that using the existing deterministic method in this case. Parametric analyses show that the imprecise random field of concrete cover (Cd) has the greatest effect on the cumulative probability of corrosion initiation, followed by initial surface chloride concentration (Cs) and chloride diffusion coefficient (Da). Compared with the interval coefficient of variation and correlation length, the cumulative probability of corrosion initiation is more sensitive to the interval mean, especially the interval mean of Cd. Additionally, the effect of interval correlation length of Cs is sequentially greater than that of Cd and Da.