Dynamic corrosion-induced cracking process of RC considering effect of initial defects

Abstract

In this paper, a model of the dynamic corrosion-induced cracking process of reinforced concrete (RC) structures considering the influence of initial defects in concrete cover caused by settlement of concrete is presented. Formulas for predicting time to initial defects initiation, time to cover cracking, threshold expansive pressure and critical weight loss of reinforcing steel are proposed. Comparisons with published experimental data show that the predictions given by the present model are in a good agreement with the experimental results and have better precision than other existing models. Finally, the influences of initial defects on critical corrosion-induced cracking indexes, such as time to initial defects initiation, time to cover cracking, threshold expansion pressure and critical weight loss of reinforcing steel are investigated. It was found that the initial defects have a great effect on critical corrosion-induced cracking indexes. These critical indexes decrease sharply when the size of initial fine crack is less than 1 mm or its number is smaller than 2 respectively, but tend to moderate when the size of the initial fine crack is more than 1 mm or its number is larger than 2. Therefore, it is important to improve the compactness of concrete in order to improve the durability of RC structures.