Investigations into the development of corrosion induced cracks in mortar
Résumé
This paper describes the deterioration of reinforced mortar specimens by cracking and debonding due to the damage of the steel-mortar interface by corrosion. As corrosion of steel in mortar is a slow process, accelerated corrosion tests have been carried out by impressing an anodic current to the rebar in order to enhance its corrosion. Different experiments have been performed on two types of specimens: (i) on reinforced mortar beams with rebars located either in the middle or at the corner to study the propagation of cracking and (ii) on reinforced mortar plates to study the inception of cracking and the debonding process. Various measurements have been recorded: (i) strain gauges stuck of the surface, evolution of the potentiel drop between steel and the counter electrode and (ii) digital image correlation. The experiments allowed determining times to damage related to crack propagation and debonding. Development of damage around the rebar has been correlated with the evolution of the bond properties. The results showed that the kinetic of cracking and the crack pattern depend upon the position of the rebar too. Time to cracking has been predicted using analytical modelling (hollow cylinder subjected to inner pressure) taking into account the crack pattern.