Nondestructive methods for determination of reinforcement steel corrosion in concrete

Corrosion is the result of the reaction between a material and its environment. Corrosion of the rebar steel may occur under certain conditions in the reinforced concrete structures. The combination of concrete and reinforcement steel was considered optimal, but the practice has revealed the insufficient durability of these structures, the main factor of structural deterioration being the corrosion of reinforcement in concrete. The maintenance and repair of bridges and buildings for their safety requires effective inspection and monitoring techniques for assessing the reinforcement corrosion. Providing of structural safety, that is, regular maintenances and timely repairs require application of efficient techniques of monitoring and control of corrosion of reinforcement in concrete. These methods should enable identification of the degree of damage, and thus indicate the severity of the problem at the moment of inspection. This paper deals with implementation of various non-destructive methods of detection and monitoring of progress of reinforcement corrosion process in concrete, with the emphasis on the method used by CANIN (Corrosion Analyzing Instrument) apparatus. The principle of the method is based on the measuring of the electric potential which is detected on the surface of concrete and which is generated as a result of the electro-chemical corrosion process of the reinforcement.