The effects of three types of rubber on the behavior of asphaltic concrete (ac) mixes have been investigated by first determining the changes that rubber additives have on the properties of the bitumen binder. Changes in penetration, softening point, and penetration temperature susceptibility with rubber-bitumen blends are reported. Force ductility tests were also carried out to investigate the changes in the properties of rubber-modified binders at low temperatures. The marshall method was used to determine changes in optimum binder content consequent to incorporation of rubber into the mix. Flexuraltesting of beam specimens was carried out using cyclic loading to investigate the changes in the fatigue properties of ac mixes caused by the addition of rubber. Within the limitations of the experimental work, the incorporation of the rubber into binders generally improved the properties of binders and mixes as determined by laboratory testing. This paper appears in transportation research record no. 1269, Asphalt mix materials and mixtures 1990.
Abstract