Cathodic protection of steel in concrete using conductive polymer overlays

This paper presents the results of a study of the effectiveness of sacrificial anodes in preventing the onset of pitting corrosion in chloride contaminated concrete using zinc overlay and a conductive coating in cathodically protected chloride contaminated slabs. Experimental tests were carried out on reinforced concrete slabs with steel embedded both in chloride free concrete and chloride contaminated concrete in order to compare the effects of sacrificial anodes on passive steel and on corroding steel. Results have shown, that sacrificial anodes may be more effective in preventing corrosion initiation (i.e. in providing cathodic prevention) than in controlling ongoing pitting corrosion (i.e. in guaranteeing cathodic protection). Monitoring criteria for this type of prevention are also discussed.