Cathodic protection of reinforced concrete

Abstract

Steel reinforcement embedded in concrete is normally protected from corrosion by the formation of a thin passive surface film in the highly alkaline environment provided by the cement paste and pore solution surrounding the steel. Atmospheric carbon dioxide reacts with the alkaline cement paste reducing the level of alkalinity, a process known as carbonation. Steel in carbonated concrete is no longer protected and in the presence of moisture and oxygen can corrode freely. Alternatively, the presence of sufficient quantities of chloride ions at the surface of the steel can cause local depassivation of the reinforcement resulting in pitting corrosion. Chloride ions may be present as a result of admixtures in the original mix or permeation into the concrete from external sources, such as road de‐icing salts or sea spray.

Citation

Lambert, P. (1995), "Cathodic protection of reinforced concrete", Anti-Corrosion Methods and Materials, Vol. 42 No. 4, pp. 4-5. https://doi.org/10.1108/eb007361