On the mechanism of steel corrosion in concrete: the role of oxygen diffusion

The generally accepted view of the corrosion of steel embedded in concrete assumes that the reduction of oxygen supports the overall process of corrosion in this medium. The results presented in this Paper show that under certain circumstances the corrosion rate may be high, even though the supply of oxygen is small or negligible. Therefore, the corrosion mechanism appears to require the existence of some cathodic process which does not require oxygen diffusion. The existence of crevices at the steel/concrete interface affording relatively low pH environments, is presented as a possible explanation for the high corrosion rates of steel in concrete without oxygen. The existence of crevices is ensured by the heterogeneity of concrete.