Information on research, handling techniques and case studies in recycling asphalt shingles were all part of the Second Asphalt Shingles Recycling Forum, which took place April 13-14 in Minneapolis. The event featured several speakers who discussed issues facing the industry today, and also allowed the more than 100 participants to talk to their peers from across the country.
The focus of the presentations was mostly on using recycled shingles in hot-mix asphalt, although other end products were also discussed. The forum was sponsored by the Minnesota Department of Transportation (MnDOT), Minnesota Office of Environmental Assistance, U.S. EPA Region 5 and the Construction Materials Recycling Association. It was partly funded by the Recycled Materials Research Center (RMRC), Durham, N.H.
Among the speakers was Jeff Melton of RMRC, who reported that the barriers to asphalt shingle recycling are both real and perceived, but that quality control and quality assurance on the parts of the shingle processor and asphalt producer are important to overcome those barriers.
Dave Newcomb, currently with the National Asphalt Pavement Association (NAPA), was at one time part of MnDOT and participated in that agency’s groundbreaking research 10 years ago on recycled shingle use in hot mix. He stated that the results, which were positive for the process, are still valid today.
He also added that NAPA believes that additions to hot mix, such as recycled shingles, needs to meet three criteria: the end product should not be hurt by use of the waste; that use of the waste should not affect worker safety and health, nor have any other detrimental environmental effects; and, the practice is economically feasible. The organization also contends that the use of the recycled debris should not be mandated.
Kent Peterson of CMRA-member Bituminous Roadways, Minneapolis, was the first of many recyclers who related their experiences recycling shingles. His company is in the process of a pilot project on using post-consumer shingles for non hot-mix products, although for more than five years his company has been grinding and adding shingle manufacturers’ debris into its hot mix plant. He feeds the shingles into the plant through the recycle bin, he says. While now asphalt that uses shingles is accepted by many customers, at first he had to overcome the perception that it was “garbage” in the mix and a health hazard. After it was explained this was untrue, he was able to grow the business.
Bob Ayres of Allied Blacktop, Eau Claire, Wis., another CMRA member, shared his company’s experience using recycled shingles in hot mix. His company has only been doing it for a few years. In his operation the shingles are added at a rate of 5 percent, and using the material reduces the need for asphalt emulsion as much as 4.9 percent. With emulsion going for around $200 per ton, that can be a tremendous savings. Allied Blacktop will experiment with new mix designs, including adding shingles to make up as much as 10 percent of the mix.
Randy Williams of Roofing Recycling Center, Portland, Ore., also shared his company’s experiences using tear-off shingles in a variety of end uses. He shared the fact that Vulcan Materials has done testing on processed shingles from his site, and while the large aggregate company with hot-mix plants in his area would not divulge the results, they were positive enough that the two companies are now negotiating to work together.
Dale Decker, a consultant and expert on asphalt based in the Toledo, Ohio area, spoke on the economics of using recycled shingles in hot mix. He recommends that shingle recyclers don’t get the material too wet during grinding, as that moisture will require the hot mix plant to use more fuel to burn off the moisture, and to handle the product properly to make sure there are no contaminants in it. In general, Decker said, shingles added at a rate of five percent can save 70 cents per ton of asphalt.