Evaluation of concrete durability due to carbonation in harbor concrete structures

The corrosion of steel bars due to carbonation is a major factor affecting the durability of reinforced concrete, thereby decreasing the long-term performance and safety of concrete structures. This research thus evaluated the effect of carbonation harbor concrete structures and quantified its influence based on in situ data tests at 436 points in 80 harbor facilities. The relationships between the carbonation depth and the cover depth; and between the carbonation depth and the concrete strength were studied. In addition, the failure probability of durability, or the initiation probability of steel corrosion, was evaluated on the basis of the reliability concept. Results of in situ tests showed that the ratio of carbonation depth to cover depth was less than 0.2 for harbor concrete structures. In most cases, the failure probability of durability by carbonation was less than 10%. Therefore, it could be concluded that the influence of carbonation on the durability of harbor concrete structures is not as significant its influence on the durability of other concrete structures such as building interiors or subway tunnels.