Microstructure and diffusion coefficient of an old corrosion product layer and impact on steel rebar corrosion in carbonated concrete

Stéphane Poyet (1, 2) , Wissem Dridi (3, 2) , Valérie L’hostis (4, 2) , Dietmar Meinel

1 LECBA - Laboratoire d'Etude du Comportement des Bétons et des Argiles
2 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
3 EDF R&D - EDF R&D
4 CEA - Commissariat à l'énergie atomique et aux énergies alternatives

Corrosion is the major degradation pathway affecting reinforced concrete structures. In the long-term, the rust layer might become thick and slow down the diffusion of oxygen from the atmosphere to the steel. With this in mind, the mineralogy, microstructure and diffusion properties of an old and thick corrosion product layer were investigated. Despite the presence of macropores, the gas diffusion coefficient was found to be low. The impact of the layer on the oxygen diffusion was evaluated using Fick’s law. The results showed that the layer could reduce the flux of oxygen only in a specific configuration.

Keywords: Steel; Steel reinforced concrete; Rust; Interfaces

Domains: Nuclear Theory [nucl-th]; Nuclear Experiment [nucl-ex]

Stéphane Poyet, Wissem Dridi, Valérie L’hostis, Dietmar Meinel. Microstructure and diffusion coefficient of an old corrosion product layer and impact on steel rebar corrosion in carbonated concrete. Corrosion Science, 2017, 125, pp.48-58. ⟨10.1016/j.corsci.2017.06.002⟩. ⟨cea-02381278⟩