ABSTRACT
Groups of specimens are being broken open at intervals so that the reinforcement can be examined directly for the extent of corrosion in comparison with unprotected controls. Two demolitions have been carried out so far, one after 18 months and the other after 32 months exposure. Results from the trial (2) have clearly indicated that CP is effective in reducing if not eliminating the corrosion that occurs in reinforcement exposed to chlorides. Control specimens which had not been cathodically protected were heavily stained with rust on the concrete surface and extensive areas of corrosion were apparent on the reinforcement when the specimens were broken up. The cathodically protected specimens were generally free of external rust staining and reinforcement corrosion was much reduced in comparison with the control specimens. The corrosion that did occur in the cathodically protected specimens might not have resulted entirely from a lack in efficacy of CP. Some initial rusting might have occurred in the 2 months before the CP system was switched on. Also, deterioration of the conductive coating anodes that occurred periodically during the trial reduced current supply and that might have allowed corrosion in some areas until the anodes were renewed.
