Rubber-modified asphalt pavements have been used in Sweden and the United States since the late 1960's. Rubber-modified asphalt concrete consists of ground recycled tyre rubber particles 6.4 mm (1/4 in. minus) added to a gap graded aggregate and then mixed with hot asphalt cement. This paving system distributed under the trade names "Skega Asphalt", "Rubit" or "Rubtop" in Scandinavia and "PlusRide" in the United States, was found to provide a new form of wintertime ice control because of the increased flexibility and the action of protruding rubber particles. Based on a review of several case histories presented herein, the resultant paving mixture appears to have the following important characteristics for cold regions applications: (1) improved resistance to load induced tensile cracking and low temperature thermal contraction cracking; (2) improved skid resistance under ice conditions; (3) good resistance to studded tires and/or chains; and (4) reduced tire noise levels. Observations of the skid reduction benefits under icy road conditions have been made with a Tapley Brake Meter in the United States. Tests by the Alaska Department of Transportation and Public Facilities indicate that significant reductions in city road stopping distances nearly always resulted from the use of the rubber modified asphalt paving system. For 21 testing dates over three winters, stopping distances were reduced by an average of 25 percent. The effectiveness of rubber modified asphalt concrete ("Rubit") has been investigated by Swedish road authorities in several field investigations. The field observations indicated the accidents related to surface frost have been completely eliminated in the areas with rubber modified asphalt pavement.
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