Evaluating Carbonation-Induced Corrosion Initiation Reliability Index for Reinforced Concrete Sections Exposed to Severe Maximum Temperature Levels

The purpose of this research is to evaluate the carbonation depth and the probability of carbonation-induced corrosion initiation (PCICI) values across various temperature levels for concrete mixes, including various percentages of fly ash (FA). The concrete sections are subjected to a combination of severe peak temperatures and CO 2 concentrations. Moreover, the maximum temperature levels varied from 25°C to 45°C, reflecting their effects on the diffusion coefficient. The concrete cover (CV) thicknesses used in the probabilistic corrosion model range from 40 mm to 70 mm. The width of the crack (CW) variability ranges from 0.05 to 0.25 mm for cracked sections to determine their effect on probabilistic corrosion initiation. The concrete mixes include various percentages and types of FA, ranging from 5% to 30%, as supplementary cementitious materials (SCMs). The Monte Carlo simulation method is used in conducting the probabilistic corrosion model due to its accuracy. It was deduced that, for a cracked concrete section with a CV of 70 mm and a CW of 0.1 mm, PCICI is significant at 5% when low-calcium fly ash (LCFA) is utilized in the concrete mix, exposed to various severe temperature levels exceeding 30°C. Finally, the impact of using 30% LCFA as SCM poses a high risk on PCICI for uncracked CV of 45 mm, when subjected to maximum temperatures ranging from 35°C to 45°C.