ROOFING SHINGLES AND TONER IN ASPHALT PAVEMENTS

Existing information on the use of roofing waste in hot mix asphalt (HMA) was obtained from reviews of published and unpublished literature and interviews of cognizant individuals. Ground waste roofing is available from at least 3 locations in Texas. Laboratory testing was performed on HMA containing roofing manufacturing waste (new roofing) and consumer (tear off) roofing waste. Two types of HMA were modified with ground roofing and tested in the laboratory: dense-graded and coarse matrix-high binder (CMHB) surface mixtures. Roofing waste was added to HMA at 5% and 10% and the engineering properties of the resulting HMA mixtures were compared to untreated mixtures. Laboratory tests consisted of Hveem stability, indirect tension, resilient modulus at several temperatures, moisture susceptibility, Texas Department of Transportation static creep, air void content, and voids in the mineral aggregate (VMA). The findings indicate that roofing waste is a viable waste stream that has utility in HMA. It should be possible to incorporate 5% or less roofing waste into typical HMA paving mixtures and have a product that will meet the standard quality control specifications. Because of the relatively higher VMA and asphalt film thickness, a CMHB mixture may be more capable of accommodating roofing waste than a dense graded mixture. Standard procedures for mixture design and quality control appear satisfactory for HMA containing roofing waste. Materials specifications and construction guidelines for using roofing waste in HMA paving mixtures were developed. The use of waste toner (dry ink) in asphalt is briefly mentioned on pages 11-12.