Protection of reinforcement by concrete repair materials against chloride-induced corrosion.

Specimens made from twelve types of repair material have been exposed to chlorides and the time to corrosion and corrosion rates of embedded steel bars determined. Control specimens of a good and a moderate quality concrete have also been assessed. The results have highlighted differences in performance between the materials and shown that some provide good protection against chloride-induced corrosion. Six of the repair materials were used to repair spalls in small reinforced concrete slabs. The performance of the interface between the parent concrete and repair material has been shown to be critical, allowing relatively easy ingress of chloride in many cases. Initiation of corrosion was frequently much earlier than would have been expected from the results of single material specimens, with intense anodic sites forming on the steel at the interface. (A)