Cathodic Protection of Steel Reinforced Concrete Structures Using a Galvanic Zinc Hydrogel System

Abstract There are over 500,000 condominium units along the Florida coastline, most of which have experienced significant corrosion of their steel reinforcements due primarily to chloride intrusion from the ocean salt spray. Some of the condominium associations in Florida have in the past five years recognized that cathodic protection is the only rehabilitation method that will truly prevent the corrosion of the reinforcing steel and the resultant concrete spalling and delamination. The installations of a galvanic zinc-hydrogel system will be described in detail, and monitoring data will be presented for at least six months of active service. The system consists of a 10-mil zinc foil bonded to an ionically conductive hydrogel adhesive, which is applied directly to the surface of the steel-reinforced concrete. A copper wire connects the zinc anode to multiple steel rebars. The performance is monitored by measuring the current flow in the wire, by measuring the amount of zinc consumed or, more generally, by taking depolarization readings at regular intervals. All of these measurements are an indication of the performance of the galvanic system and the corrosion of the steel rebars that is being prevented.