Long-term corrosion of rebars embedded in aerial and hydraulic binders – Mechanisms and crucial physico-chemical parameters

Abstract The prediction of long-term behaviour of reinforced concrete structures involved in the nuclear industry requires the comprehension of the mechanism involved in long-term corrosion. Yet, studies on archeological artefacts allowed to identify a typical layout constituted of four layers: the metal, the dense product layer (DPL), the transformed medium (TM) and the binder. Oxygen reaction sites were labelled using oxygen 18 ( 18 O) and it was evidenced that the cathodic sites are located at the metal/dense product layer interface. So, oxygen has to crossed the DPL to react at the M/DPL interface or inside the marblings, and measurements of the effective tritiated water (2.6 ± 0.1 × 10 −11 m 2 /s) and iodide (1.0 ± 0.3 × 10 −11 m 2 /s) diffusivity of this layer saturated with water were made. Indeed, these two molecules have a diffusivity in water very closed to oxygen diffusivity.