Although asphalt rubber recycling is typically frowned upon as it is understood to entail greater emissions than conventional-mix asphalt, this article relates that recent research indicates that rubber’s flash point is higher than that of liquid asphalt. Reclaimed asphalt pavement (RAP) became thought of as a high-pollutant from the blue smoke it produced when improperly recycled in plants which were not designed for it. However, a hot-in-place test in Arizona has demonstrated that emissions can be mitigated if it is processed properly. This type of asphalt consists of 15 to 22 percent crumb rubber obtained from reclaimed tires. When added to liquid asphalt, the procedure is known as a “wet process”, where rubber crumb reacts with liquid asphalt. It differs from the “dry process”, in which the asphalt crumbs are added with stone to form a different type of aggregate. The growing demand for RAP is demonstrated in Arizona’s Quiet Pavement Pilot Program, where the focus is directed at reducing tire/pavement noise on Arizona roadways. Research has found that rubber asphalt binder used on the surface of roadways can lead to a noise abatement of up to 4 dBA. Recent research by the California Department of Transportation (Caltrans) supports the viability of full-depth pavement reclamation, hot plant recycling, cold in-place recycling (including foamed asphalt), and hot in-place recycling. Additional studies on emission rates are also supportive, showing that rubber asphalt emission rates of particulate and toxic compounds were lower than those set forward by the Environmental Protection Agency as acceptable rates.

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  • Supplemental Notes:
    • Page range: pp 36-38, 40, 42, 44-47
  • Corporate Authors:

    James Informational Media, Incorporated

    2720 South River Road, Suite 126
    Des Plaines, IL  United States  60018-
  • Authors:
    • Kuennen, T
  • Publication Date: 2005-10


  • English

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Filing Info

  • Accession Number: 01007025
  • Record Type: Publication
  • Source Agency: UC Berkeley Transportation Library
  • Files: BTRIS, TRIS
  • Created Date: Nov 8 2005 7:36AM