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Re-bar Corrosion in Concrete
The majority of metallised zinc cathodic protection systems are operated in galvanic or sacrificial mode. However metallised zinc cathodic protection systems can be, and are in many instances, operated in impressed current mode. The sprayed coating, a high purity zinc alloy, is connected to one pole of a DC power supply. The steel re-bars are connected to the other pole of the power supply. The electrical circuit is completed between the rebar and the zinc by the presence of moisture in the concrete. The action of the corrosion cell causes the zinc to corrode in preference to the steel re-bars, therefore protecting the re-bars from corrosion.
