C&D World: Shingle Minded

Concerns over asbestos and PAH (polycyclic aromatic hydrocarbons) contained in asphalt shingles are a major barrier to recycling the material, but the industry lacks data on the real risks, according to Dr. Timothy Townsend of the University of Florida, who spoke at a session about shingle recycling at the C&D World Exhibition & Conference recently held in San Antonio.

The primary concern of regulators is the possible presence of asbestos, which can be released into the air through processing or potentially leach into the groundwater if stored improperly. Contamination issues also extend to the use of recycled asphalt shingles in hot mix asphalt (HMA), again either through air emissions or through direct human contact with the product.

However, the industry currently lacks data on how much of these contaminants are actually present in asphalt shingles to the point where it affects whether they can be recycled, according to Townsend. “The challenge is to satisfy regulations and protect the environment without overburdening the recyclers who are trying to process the material,” Townsend said.

With the increasing price of petroleum, which is driving up the cost of virgin asphalt, using recycled asphalt shingles in an HMA product is a valuable application for the material, added Dan Krivit of Dan Krivit & Associates. In fact, Krivit said he expects the competing cost of virgin asphalt will continue to drive the use of recycled asphalt shingles for the near future.

In addition to saving HMA producers money, using recycled asphalt shingles incurs other benefits, such as conserving landfill space and added rutting resistance, especially in warmer temperatures, according to Krivit. However, Krivit added potential disadvantages to using recycled asphalt shingles in HMA include contamination when using tear-offs of nails and possibly asbestos, added cost of processing and use and increased low-temperature fatigue and cracking.

Other issues facing recyclers who process asphalt include dust control, which is important for operations as well as obtaining permits to operate, and economic/political issues like tips fees, which drive recycling in general. Additional information about shingle recycling is available at www.shinglerecycling.org. The Web site was developed by the CMRA in partnership with the U.S. EPA Region 5 and the University of Florida.

The C&D World Exhibition & Conference was Jan. 14-16 in San Antonio. More information is available at www.cdworldshow.com.