FIELD EVALUATION OF RUBBER-MODIFIED BITUMINOUS CONCRETE

The flexibility and, as a result, the durability of bituminous concrete placed as an overlay over old pavement can be increased by the addition of reclaimed rubber. The conditions under which the modified characteristics are most beneficial have not been well defined. Within the maintenance program of the Connecticut Department of Transportation, reclaimed-rubber test sections were placed at nine locations. The locations were selected to include three levels of traffic from a low of 1300 average daily traffic (ADT) to a high of 10,400 ADT and three levels of pavement condition (low, medium, and high). At each location, mixes in which the rubber content was 0, 1, and 2 percent of the mix were placed. Comparisons were made of permeability, density, skid number, and crack development over three years. (Author)