An investigation into corrosion around voids at the steel-concrete interface

In this study, the influence of voids on corrosion process at the steel-concrete interface was investigated, as the exact influence of these features on corrosion processes under various environmental conditions is not entirely understood. Coupled multi electrode arrays and electrical resistance probes were implemented to monitor the evolution of corrosion under cyclic exposure to chlorides and carbonation. MicroCT was used to determine the location and volume of corrosion damage. It was found that, in most cases, corrosion damage initiated outside the voids. During initiation and the early propagation phase, the steel beneath the voids rarely participated in the redox reaction. In following phases, various kinds of corrosion evolution were observed. Specific corrosion mechanisms were proposed and discussed to explain these corrosion processes.