To investigate the corrosion of the reinforcing steel (rebars) in bridge decks, concrete laboratory specimens with re bars were cast and subjected to a chloride environment. The corrosion potential and rate were monitored with Cu-CuS04 half-cell and three electrode linear-polarization (3 LP) devices. When active corrosion had been initiated, five rehabilitation treatment methods were applied to the corroding specimens: latex-modified concrete (LMC) overlay, low-slump dense concrete (LSDC) overlay, polymerimpregnated concrete, LMC overlay with polymer impregnation, and LSDC with polymer impregnation. The monomer system used was 90 percent methyl methacrylate (MMA), 10 percent trimethylolpropene trimethacrylate and 0.5 percent of the above monomer mix of azobisiobutyronitrile. The irppregnated specimens were grooved and dried to 230 F before impregnation and subsequent polymerization. The posttreatment corrosion rates were used for analyzing the effectiveness of the various treatment methods. The treatment methods investigated were able. to reduce the corrosion rate dramatically compared with untreated specimens. However, the difference in effectiveness among the five methods was insignificant.

Premature deterioration of reinforced concrete bridge decks was first recognized by highway agencies in the late 1950s. An initial study determined that the principal cause was spalling, which resulted from corrosion of the reinforcing steel caused by the high chloride content of the concrete and moisture intrusion (1, 2). The major source of chlorides is the deicing salts applied to the roadways during winter. In 1970, more th4n 9 million tons of deicing salts were used in the United States (3), increasing to 12 million tons by 1979 (4). A second source of chlorides is sea water in direct contact and from spray on bridge components in a marine environment. By the 1970s, highway agencies had begun to identify the enormous cost involved in the repair and rehabilitation of. deficient bridges. It was found that the number of bridges that became deficient each year far exceeded the actual number of bridges t_hat were repaired in the same time frame. As a result, an increasingly large backlog of deficient bridges was created with each passing year. A recent cost estimate of the rehabilitation of bridges deteriorated by corrosion was placed at $20 billion, at an annual increase rate of $0.5 billion (5).