STEEL CORROSION OF RC CONCRETE ON CRACK CHARACTERISTICS

Reinforced concrete is in general known as a high durability material due to a strong alkalinity of cement. Probable concrete cracks could incur steel corrosion of RC structures and then could easily lead to deterioration of the concrete durability, which can be fully secured by a systematic quality control for the construction of concrete structures. For the corrosion protection of reinforcing steels in concrete, however, current design specifications of concrete cover depth do not consider in-depth the effect of the cracks as well as the chloride content of RC structures. Therefore, appropriate provisions for concrete cover depth should be coded by considering the influence of concrete cracks on the corrosion of reinforcing steels. The objective of this research is to investigate pertinent cover depth, which can prohibit rebar corrosion, on the basis of experimental corrosion measurements of reinforcing steels on crack characteristics such as the width, depth and frequency of concrete cracks. This overall experimental research is to (1) investigate the rebar corrosion which could be initiated by concrete cracks, (2) investigate the effect of corrosion inhibitors for cracked and uncracked concrete specimens, (3) establish statistical data of rebar corrosion depending on crack pattern through crack investigation on aged bridge structures, which can be used for the setup of the relation between crack properties and rebar corrosion, and (4) investigate a long-term behavior of rebar corrosion of concrete specimens depending on their crack patterns, which have been exposed to marine environment in the west coast. It is understood that steel corrosion of RC concrete should take a long time even under the severe environmental conditions. Corrosion measurements for the test conducted during the last one and half years have shown that steel corrosion has not been fully developed yet. This paper presents only the initial corrosion status of cracked and uncracked test specimens in the laboratory. (a) For the covering entry of this conference, please see ITRD abstract no. E204151.