Potential Use of Tire Rubber and Ebonite in Asphalt

This report evaluates the effectiveness of rubber-asphalt and ebonite-asphalt mixes based on a review of published literature and unpublished reports. It discusses in detail various aspects of these mixes, including: diffe ent applications, physical properties, experiences of state highway agencies, and claimed advantages and problems associated with their use. The addition of ground tire rubber in asphalt significantly changes the physical properties of the mix. In general, physical properties, i.e., viscosity, elastic recovery, fatigue life, of rubber-asphalt mixes are much better than those of conventional asphalt. Although rubber-asphalt mixes have superior physical properties, they have performed either only slightly better or equal to conventional asphalt mixes in the field. The salient problems associated with rubber asphalt mixes which restrict their use are: stickiness, high cost, and air pollution. The cost of rubber-asphalt mixes is much higher than conventional asphalts, and there is little evidence that rubber-asphalt mixes will have an increased service life sufficient to justify the high costs. Based on the experiences of most of the states, it is recommended that use of rubberasphalt mixes not be encouraged until INDOT acquires first hand results from pilot projects. Ebonite-asphaltic mixes have possible applications assuming that the ebonite can be economically cleaned of lead contamination.