A study on carbonation in concrete structures at existing cracks

Abstract

The carbonation depth of concrete is an important index for evaluating the damage and durability of reinforced concrete structures. In this paper, the main purpose focuses on the study of carbonation problems of concrete structures at existing cracks. The carbonation process of concrete structures at cracks consists of four steps: diffusion of CO₂ into the crack, diffusion of CO₂ into the concrete, chemical reaction, and diffusion of hydroxyl ions. The present study indicates that the coefficient of carbonation rates of both uncracked and cracked concrete structures follow normal distribution. As regards the pure process of carbonation, the same basic interrelations given for uncracked concrete are valid for carbonation in the crack regions as well. Carbonation can penetrate into the interior of cracked concrete much faster than it does through uncracked concrete. Under static loading of existing reinforced concrete structures with cracks, the carbonation depth at a constant crack width can be predicted by using statistical methods.