Challenges in Characterization of Recycled Asphalt Shingles

Using recycled asphalt pavement (RAP) in asphalt concrete has been practiced for decades. Recent attention has been mostly placed on increasing the amount of RAP, as well as using recycled asphalt shingles (RAS) in asphalt concrete. Use of RAS in asphalt concrete poses special challenges as it includes very stiff binder and mastic. There are two types of RAS used in asphalt concrete: one is scrap asphalt shingles coming from manufacturing waste and other is the post-consumer waste. In either case, it is important to understand the properties of the RAS binder and consider those properties in an engineering design for incorporation into asphalt concrete. Recovering and laboratory testing of the RAS binder does not follow conventional techniques due to high stiffness. Research was conducted to find suitable techniques for determination of RAS binder characteristics at both high and low temperatures, and a guide was developed on the best approach for recovery and testing of the RAS binder.