Guidelines for the Use of Reclaimed Asphalt Shingles in Asphalt Pavements
Recent price fluctuations in asphalt cement have encouraged asphalt mix producers in the U.S. to seek ways of reducing or extending the virgin asphalt ce- ment they use in their products with continued industry emphasiS on quality and environmental assurances. The most practical approach in the short term is to use the binder available in reclaimed asphalt pave- ment (RAP) and reclaimed asphalt shingles (RAS). The industry has long realized the value of RAP for saving money and conserving resources. More re- cently the industry has also come to realize the value of asphalt shingles since they contain anywhere from 19 to 36 percent of liquid asphalt (Townsend, Powell, & Xu, 2007). Therefore, even a small percentage of shingles can have a significant effect on the amount of new asphalt binder added to the mix. As shown in Figure 1, asphalt shingles contain other materials, including fibers, fine aggregate and mineral filler which are also commonly used in asphalt mixtures. Table 1 presents the typical range of composition for organic and fiberglass asphalt shingles.