Associate research consultant, Research Laboratory, United States Steel Corporation, Monroeville, Pa.
Pages: 26 Published: Jan 1977
Chloride-induced corrosion of the reinforcing steel in concrete is a major cause of premature concrete deterioration. This presentation describes the results of an investigation sponsored by the National Cooperative Highway Research Program (Project 12–13) into the use of cathodic protection as a method of suppressing the corrosion of reinforcing steel in highway bridge concrete decks. The principal cause of bridge-deck corrosion is salt used for snow and ice removal. In this study, factors affecting the cathodic protection of steel reinforcement in concrete were investigated, and a variety of impress-current and sacrificial-anode approaches to cathodic protection of bridge decks were examined in laboratory and model testing.
The results of electrochemical studies showed that corrosion can be controlled by the application of cathodic current to corroding steel in concrete. The minimum protective potential for cathodic protection was established. Studies showed that cathodic-protection current can result in a decrease in bond strength between the steel and the concrete. However, the decrease would be slight at the anticipated conditions of protection.
A method previously developed by the California Department of Transportation was examined in depth, and it was concluded that this method offered promise as an impressed-current system. A sacrificial-anode design with zinc anodes also was determined to hold promise.
corrosion, concretes, reinforcing steels, deterioration, chlorides
Paper ID: STP27960S