Investigation of Rheological Properties of Asphalt Rubber toward Sustainable Use of Scrap Tires

About 300 million scrap tires are generated each year in Unites States. The improper disposal of these scrap tires has posed serious threat to public health and environmental safety over the last few decades. The objective of this study is to assess the viability of sustainable utilization of scrap tires as ground tire rubber (GTR) to prepare new asphalt rubber (AR) by investigating their rheological and mechanistic properties. AR is reported to provide a longer lasting road surface, reduced road maintenance, reduced noise, and shorten breaking distance. The current study has gathered lessons learned and best practices from prior studies. Toward evaluating the mechanistic performance, three different amounts (10%, 15%, and 20%, by the weight of the binder). GTR have been blended with a base binder (PG 64-22) to prepare AR binder samples though the wet process and their rheological properties were tested in accordance with Superpave test protocols. Viscosity and penetration test results reveal that AR is significantly stiffer and it possesses higher rutting resistance compare to the base binder. Preliminary test data and life cycle cost analysis of a typical pavement section suggest that AR is a viable and sustainable alternative to the commonly used polymers.