Principles of the cathodic protection of atmospherically exposed concrete structures are described. The various protective effects induced by the cathodic polarisation, the differences between the cathodic protection applied for controlling the corrosion rate of chloride-contaminated constructions and that applied to improve the corrosion resistance of the reinforcement of new structures expected to become contaminated are then underlined and discussed. The more recent applications of cathodic protection to carbonated concrete are also illustrated.

The operating conditions (voltage and current applied), the throwing power, the protection conditions which avoid the risk of hydrogen embrittlement in prestressed structures are also discussed.