Corrosion propagation in cracked reinforced concrete, toward determining residual service life

摘要

Durability of reinforced concrete (RC) is influenced by cracks, providing paths for ingress of corrosion agents and early corrosion initiation. The corrosion propagation stage has in recent years been the focus of investigation, however, mainly focused on a single crack and reinforcement bar. This study focuses on chloride-induced corrosion in three reinforcement layouts with a single or two transverse cracks kept at a constant crack width in flexure. The 27 beams were subjected to cyclic ponding with chloride aqueous solution for 36 weeks, and corrosion rate and potential measured weekly. The results indicate that the corrosion rate of RC members is influenced by crack spacing and reinforcement quantity. In current practice, corrosion initiation indicates end of service life. However, corrosion initiation is quick in cracked regions. It is proposed here to base the residual structural service life on the corrosion rate in the propagation phase, and a limit state of a threshold loss of reinforcing steel. In addition, crack spacing and reinforcement density are to be considered in the prediction of residual service life.