X-ray Radiography to Visualize the Rebar-Cementitious Matrix Interface and Judge the Delay in Corrosion through Self-Repair by Encapsulated Polyurethane

Corrosion of steel reinforcement is one of the most detrimental attack mechanisms for reinforced concrete structures. The presence of cracks, which are inextricably linked to reinforced concrete, accelerates this attack mechanism. The aim of this study is to heal cracks by an autonomous mechanism, which is triggered upon crack appearance. With an accelerated corrosion test on mortar samples with embedded reinforcement bars, it is shown that the presence of cracks indeed accelerates the onset and propagation of corrosion at the interface between the rebar and the cementitious matrix. Moreover, it is shown that crack healing in both the traditional, manual way and the proposed autonomous way, with an encapsulated one-component polyurethane, delays the onset and propagation of corrosion. The difference in corrosion behavior is proven by visual evaluation of the rebar surface and by X-ray radiographic analysis, which is proposed as a successful technique to evaluate the crack healing efficiency and more specifically the potential to delay corrosion.