In this study a variety of impressed-current and sacrificial-anode approaches to cathodic protection in the laboratory and in prototype testing was examined. A sacrifical-anode design using zinc ribbons in combination with an essentially nonconductive asphaltic concrete overlay was determined to hold promise if problems associated with low driving voltage and expansion of anode corrosion products can be overcome. Accomplishment of the study should be of value to any field evaluation studies of cathodic protection of bridge decks that are undertaken. With the California Department of Transportation in the forefront, several agencies are now conducting field evaluations of the impressed-current approach to cathodic protection. The sacrificial-anode approach is the subject of an on-going NCHRP study (Project 12-13A). The field evaluations should provide answers to the questions being asked about the long-term effectiveness of the systems in protecting steel against corrosion, the resistance of this systems to physical damage, and the possible adverse effect of the bituminous concrete overlays on the durability of the underlying concretes. (Author/publisher)
Samenvatting