Prevention of corrosion of steel reinforcement in concrete

Abstract

Premature failure of reinforced concrete structures occurs primarily due to early corrosion of steel reinforcement. These reinforcements are prevented from corrosion by the formation of a passive oxide film in the high pH environment of concrete. However, pH decreases in actual conditions due to the ingress of harmful ions like carbon dioxide, sulphur dioxide, chloride, etc., leading to localized corrosion. In view of the intensity of the problem, serious efforts have been made to prevent corrosion of reinforcement. These have led to the development of varying types of prevention techniques/measures including coatings, electrochemical techniques like cathodic and anodic protection, inhibitors, control of concrete mix and reinforcement with superior corrosion resistance. These preventive techniques have inherent advantages and disadvantages with respect to the type of structure and the surrounding environment.