Influence of pre-existing oxides layer and interface condition with carbonated concrete on active reinforcing steel corrosion

This work focuses on carbonation‐induced corrosion in concrete. This paper presents specific experiments which were developed in order to assess the influence of both pre‐existing oxides layer at the surface of the steel bars and steel–concrete interface condition on active corrosion. Two types of active corrosion are studied: Microcell corrosion and galvanic corrosion. Results show that pre‐existing oxide layer contributes to reduce both galvanic and microcell corrosion. Steel–concrete interface defect leads to a strong increase in galvanic corrosion but does not affect significantly microcell corrosion in carbonated concrete. The quantity of pre‐existing oxides is highly scattered and these scatters can be superior to the mass of new oxides formed during relatively short‐term corrosion tests in natural condition which makes mass loss analysis very difficult.