Rehabilitating Corrosion Damaged Bridges Through the Electrochemical Migration of Chloride Ions
D. G. Manning and A. K. C. Ip
Appears on pages(s):
anodes; bridges (structures); chlorides; columns (supports); corrosion; Structural Research
The concept of applying electrical current to concrete to move chloride ions away from the reinforcement has been known for many years, but only recently have practical techniques been developed. Paper describes, in chronological order, the treatment and performance of three structures in Ontario and a summary of theoretical and model studies undertaken in support of the field activities. In 1989, a section of a large bridge pier was treated with a commercial electrochemical migration process developed in Europe. The same process was used to treat the spirally reinforced columns on a freeway overpass in 1990. An alternative electrochemical migration process, developed under a SHRP contract, was applied to portions of the concrete abutments of a bridge in Northern Ontario in 1992. A novel aspect of the treatment was the use of lithium borate in the electrolyte to suppress any negative effects of the treatment on alkali-silica reactivity in the concrete. Recommended criteria for the selection of candidate structures and for treatment parameters are presented.