Corrosion of steel in cracked concrete: A microscale study

摘要

The influence of concrete cracking upon reinforcement corrosion is complex. Cracks allow fast penetration of chlorides, potentially leading to a shorter initiation period of reinforcement corrosion. Structural regulations control acceptable crack width values based on the exposure class of the structure. These regulations are limited to crack width values at the concrete surface but do not account for the influence of cracks at the concrete-steel interface. Research studies on corrosion of reinforcement embedded in cracked concrete have shown that the correlation between cracks and corrosion is rather complex. Studying the condition of pitting in steel reinforcement embedded in cracked concrete from a microscopic approach could lead to insights on the mechanisms of corrosion under this condition. In this research, reinforced concrete specimens were subject to cracking. Subsequently, the specimens were exposed to salt-dry cycles with a chloride solution while continuously monitoring of open circuit potential (OCP), linear polarization resistance (LPR) and electrical resistance of concrete. Visual analysis of corrosion pits of steel bars showed that a correlation between crack width and pit dimensions was found.