An evaluation of reclaimed asphalt shingles in hot mix asphalt by varying sources and quantity of reclaimed asphalt shingles

The practice of incorporating reclaimed asphalt pavement (RAP) into hot mix asphalt (HMA) is common within the paving industry as a cost-effective source of quality paving binder and aggregate. Recently, research efforts have focussed on investigating the potential of using reclaimed asphalt shingles (RAS) in HMA. This study provides a comparison of the laboratory performance of several HMA mixtures with varied RAS sources and contents. Performance testing for the mixtures included dynamic modulus and phase angle. Fatigue testing was also performed for several of the mixtures. Mixtures with higher amounts of binder replacement from RAS showed stiffer performance at high temperatures and less stiff performance at low temperatures. The mixture with greater amounts of RAS showed better fatigue performance. The mixtures with various sources of RAS, whether pre- or post-consumer, showed similar low-temperature performance, while the mixture with a blend of both sources was stiffest at high temperatures. A set of mixtures comparing different RAS sources was also compared with a mixture containing RAP as the only recycled binder source. The results of testing of these mixtures showed that the RAP mix was stiffer at intermediate and high temperatures but had similar results to the RAS mixtures in low-temperature performance.