There are different remedial methods that can be applied, as part of rehabilitation of existing concrete structures, for controlling chloride-induced reinforcing steel corrosion. Each of the methods, which are used after all damaged concrete in a structure have been removed and patched, functions by one of the following principles (reference):
Providing a barrier on the surface of the existing concrete to prevent fixture ingress of chloride. The conventional rehabilitation methods belong in this category.
Modifying the concrete environment to make it less corrosive. This is how electrochemical chloride extraction can extend the service life of chloride-contaminated concrete structures.