Corrosion of Steel in Concrete & Assessment Techniques, Sergi

Concrete is a porous material whose pores contain an electrolyte made up primarily of sodium and potassium hydroxides. Steel reinforcement is normally protected in such an electrolyte owing to the formation of a dense and uniform passive oxide film. Carbonation of the concrete (neutralisation of the alkali constituents by CO2 gas from the atmosphere), or infestation of the concrete with salt from seawater or from deicing agents leads to the breakdown of the protective oxide film and to corrosion of the steel. Corrosion of steel in concrete is an electrochemical process whereby anodic and cathodic reactions occur simultaneously on the surface of the steel resulting in the dissolution of the metal at the anodic sites. (read more)