Probabilistic analysis of reinforcement corrosion due to the combined action of carbonation and chloride ingress in concrete

This paper presents a comprehensive probabilistic model for the corrosion initiation of steel reinforcement due to the combined action of carbonation and chloride ingress in reinforced concrete structures. The coupled mechanism of the transport of carbon dioxide, chloride ions, heat and moisture is taken into account in this model. A minimum number of random variables were chosen from a sensitivity analysis to reduce the computational cost. The corrosion is assumed to be initiated when either the concentration of the free chloride ion exceeds its threshold value or the pH of the pore solution decreases to below 11. According to this model, the probability of the corrosion initiation in the above-mentioned combined action of carbonation and chloride ingress is almost two times higher than the case in which the two mechanisms are considered separately. The Kolmogorov-Smirnov test indicates that the time of corrosion initiation approximately follows a log-normal distribution in this combined action.