Cathodic protection (CP) stops corrosion and eliminates the need for periodic patching or deck replacement. Improved materials and methods have reduced costs and simplified installation of CP systems.
HOW CATHODIC PROTECTION WORKS
Cathodic protection systems use electric current to combat corrosion. In concrete, metals separated by a salt solution generate current just as a battery does. Oxidation causes rust to form where the current originates (at the anode) but there's no damage where the current's journey ends (at the cathode). To stop corrosion, a new anode is added. It's made of a metal that isn't damaged by oxidation.
Because anodes protect steel only up to about 6 inches away, anode material must be closely spaced over the entire area to be protected. An expanded metal mesh offers several advantages: light weight; it is suitable for protecting vertical surfaces and decks; and it needs only a thin concrete overlay. The base material is thin titanium sheet expanded to form a diamond-shaped mesh with 3x1 1/3-inch openings. It's coated with mixed precious metal oxides so the anodic reaction produces only oxygen.