Evaluation of roofing shingles in hot mix asphalt

Recycling waste materials is a viable solution to the expensive and environ mentally unacceptable disposal problem for these products. Approximately 9, 500,000 tons of roofing shingles are produced each year. The cost is betwee n $18 and $60 per ton to dispose of these materials. Reclaimed roofing shin gles contain hard crushed aggregate, high viscosity asphalt, and fibers tha t may be desirable for the production of hot mix asphalt (HMA) pavements. O ne source of roofing shingles was evaluated for use in HMA mixes. The roofi ng shingles used were 100% manufacturer's postproduction fiberglass shingle scraps. The properties of the HMA mixture with shingles were evaluated and compared with conventional (no shingle) HMA mixture. The amount of roofing shingles that can be added to HMA mixture is limited by the high percentag es (-0.075 mm) of materials found in the roofing shingles. A softer virgin asphalt binder should be used to account for the much stiffer asphalt in th e roofing shingles. The properties of shingle HMA mixture can be comparable to the properties of conventional HMA mixtures. In addition, shingle can b e used in stone mastic asphalt mixtures. Even with shingle added, the stone mastic asphalt may still need a polymer modified asphalt, or fiber, such a s cellulose, to control draindown.