ABSTRACT
The RC structures exposed to the marine environment are subjected to constant threat to the durability due to the chloride ions infiltrating from the surface. The chloride infiltrating to the inside of the RC structures neutralizes the alkalinity of the concrete to promote the corrosion of the concrete, resulting ultimately in the corrosion of the reinforcing steel bars inside the concrete structure. Therefore, the RC structures should be designed to improve the durability in consideration of degradation mechanism. In case of chloride attack particularly, the structure could be severely damaged. Therefore, the durability design considered LCC is performed without repair & maintenance during the life cycle. The maintenance design at a design stage, however, becomes somewhat different from the LCC design because of environmental and construction factors. In case of chloride attack, in general, it’s estimated that the physical life of the RC structures is over when the critical chloride ion concentration is exceeded a design criteria at the level of steel bars. Even though the target life is not achieved, the lifetime for the degradation should be correctly estimated and the degraded structures should be properly repaired in order to keep the target life at a minimum cost. In order to improve the durability of the degraded structures, therefore, maintenance interventions should be timely done. Besides, it’s very important to estimate the application time of maintenance interventions in terms of safety of the structure and cost efficiency.
