Abstract: The present invention relates to a method of and an apparatus (20) for cathodic protection of reinforced concrete using discrete anodes (22) in or on the reinforced concrete member (14) to improve performance and service life of the discrete anodes. The discrete anode (22) is embedded in a cementitous grout or mortar (24) to encapsulate the anode (22) and provide contact to complete the cathodic protection circuit. A lithium salt is added to the cementitous grout or mortar (24) in an amount of at least about 0.05 gram per cubic centimeter. The lithium salt functions to enhance the performance of the cathodic protection system (20) by minimizing the deleterious effects of the anode reaction products on the grout or mortar adjacent to the anode and increasing the protective current delivered to the reinforcing steel.

Abstract: Humectants are applied to cathodic protection systems which utilize thermally-sprayed zinc or zinc alloy anodes applied to the surface of reinforced concrete structures. The humectants are deliquescent or hygroscopic organic or inorganic salts, hydrophilic polymers or colloids, or organic liquid desiccants. The humectants are positioned at or near the interface between the anodes and the concrete and increase the moisture content at the interface. This increases the ability of the anode to deliver cathodic protection current to steel embedded in the concrete. The humectants may be applied to the concrete surface prior to application of the anode, or may be applied subsequent to installation of the anode.

Abstract: The present invention relates to a method of cathodic protection of reinforced concrete, and more particularly, to a method of improving the performance and service life of discrete anodes used in a cathodic protection system. The method of the present invention comprises placing an embeddable discrete anode in, or on, the reinforced concrete member. The discrete anode is then embedded in a cementitous grout or mortar to encapsulate the anode and provide contact to complete the cathodic protection circuit. A lithium salt selected from the group consisting of lithium nitrate (LiNO3), lithium bromide (LiBr), and combinations thereof, is added to the cementitous grout or mortar surrounding the discrete anode, in the amount of at least about 0.2 gram (dry basis) per cubic centimeter of grout or mortar. The lithium salt functions to enhance the performance of the cathodic protection system by minimizing the deleterious effects of the anode reaction product on the grout or mortar adjacent to the anode.

Abstract: The present invention relates to the field of cathodic protection of reinforced concrete. A conductive metal is thermally applied onto an exposed surface of the concrete in an amount effective to form an anode on the surface. This establishes an interface between the anode and the concrete. The thermal application is performed in a manner which is effective to impart permeability to the anode. A lithium salt solution selected from the group consisting of lithium nitrate solution, lithium bromide solution, and combinations thereof is applied to the external surface of the anode. The solution migrates by capillary attraction to the interface of the anode with the concrete depositing the lithium salt at the interface. The lithium salt functions as a current enhancing agent. The salt also functions as a humectant absorbing moisture from the atmosphere thereby providing an electrolyte at the interface. These combined effects substantially increase current delivery from the anode.