Laboratory Evaluation of Mixtures Incorporating GTR and RAP

Abstract

This paper presents the results of a study that was conducted to evaluate the performance of ground tire rubber (GTR) modified asphalt mixtures containing reclaimed asphalt pavement (RAP) materials and compare them to that of a typical styrene-butadiene-styrene (SBS) polymer modified asphalt mixture. Two types of GTR materials that were produced using the ambient and cryogenic methods were considered. Different laboratory tests were conducted on the prepared GTR and polymer modified mixtures to evaluate their resistance to low temperature cracking, fatigue cracking, and rutting. The results of the laboratory tests showed that mixtures prepared using the GTR modified binders had similar low temperature cracking resistance to the polymer modified mixture. In addition, the GTR mixtures had higher indirect tensile strength, but lower toughness index values than the polymer modified mixture. While the ambient GTR mixture had slightly better rutting performance than the polymer modified mixture, the cryogenic GTR mixture exhibited similar rutting resistance. In general, all GTR mixtures with RAP exhibited good resistance to low temperature cracking, fatigue cracking, and rutting.