Influence of Recycled Asphalt Shingles on Asphalt Binder Content, Mixture Stiffness, and Laboratory Rutting Performance

Recycled asphalt shingles (RAS) is a technology in which pavement costs can be reduced significantly and pavement properties may be enhanced. Also, incorporating shingles into pavements reduces the impacts of waste shingles in landfills, preserving our environment. However, for this new technology to be practical for implementation, a better understanding of how the ground shingles affect the properties of the asphalt is necessary. The purpose of this research was to examine the effects of recycled asphalt shingles on asphalt binder content, mixture stiffness, and laboratory rutting performance. For this project, shingles were added to hot mix asphalt mixtures at 2.5, 5, and 10 percent by weight of the total mix. This study showed that incorporating shingles into mixes is sometimes complex due to the interaction of a number of factors such as nominal maximum aggregate size, binder grade, aggregate type, and percent RAS. In spite of the complex behavior of these mixes, a few conclusions could be drawn. First, properties of mixes with RAS were not vastly different from their control counterparts. Second, the manufacturing waste shingles are expected to contribute more than 85 percent of their available binder to a mix. Finally, asphalt with shingles incorporated produced in industry will likely be stiffer than traditional HMA resulting in less rutting and stripping