Long-term performance and life-cycle-cost benefits of cathodic protection of concrete structures using galvanic anodes

Abstract This paper presents a market study indicating that Patch Repair without galvanic anodes (PR strategy) can lead to continued corrosion (due to the halo effect and residual chloride effect) and another major repair in about five years. Repeated patch repairs can lead to continued corrosion and eventual replacement of structures and huge life cycle cost (LCC). On the other hand, the strategy of cathodic protection using galvanic anodes (CP strategy) can enhance the service life and reduce LCC. The data on long-term depolarized potential of steel, output current from the anodes and/or visual observations indicated that the galvanic anodes were successful in controlling the chloride-induced corrosion for up to 14 and 10 years, in a jetty and industrial building, respectively. It was also found that the additional cost of galvanic anodes is only about 4% of the repair cost for the jetty structure – breaking the myth of high capital cost of CP strategy. Then, a framework to estimate the LCC of PR and CP repair strategies is developed and it is found that CP and cathodic prevention (CPrev) strategies are highly economical than the PR strategy. Also, the LCC of 30 repair projects confirmed that the use of CP strategy can lead to LCC saving of up to about 90% in about 30 years after the first repair. More importantly, the CP and CPrev strategies can enhance the service life to as long as needed by the replacement of anodes at regular intervals and at minimal cost. Also, a way forward to promote CP strategy in concrete repair industry is provided.