Cathodic protection and cathodic prevention in concrete: principles and applications

The paper deals with the principles of cathodic protection for atmospherica lly exposed concrete structures, the various protecting effects induced by the cathodic polarization and tests and field experience results. The diffe rences between the cathodic protection applied for controlling the corrosio n rate of chloride contaminated constructions and that applied to improve t he corrosion resistance of the reinforcement of new structures expected to become contaminated are then underlined and discussed. The more recent appl ications of cathodic protection on carbonated concrete are also illustrated . The operating conditions (voltage and current applied), the throwing powe r, the protection conditions which avoid the risk of hydrogen embrittlement in prestressed structures are also discussed. Examples of cathodic protect ion and of cathodic prevention are also presented.