Recycling of tear-off asphalt shingles is ready for full-scale, commercial operations.  That’s the message from two companies that sponsored a special event held in Shakopee, MN on October 21.  The main barrier is the need for a permissive materials specification from the Minnesota Department of Transportation (MnDOT).

Dem-Con Recovery & Recycling, a subsidiary of Dem-Con Companies, is a local recycling company that has recently invested in the equipment and systems needed to turn tear-off shingles into a culpable recycled product.

Once residential asphalt shingles have been sorted and cleaned to remove contaminants and then ground, the product can be introduced into the mix at hot mix asphalt (HMA) plants.

One recent study indicated that on a statewide basis, tear-off shingles recovery could reach at least 156,000 tons per year by 2012.  Given the oil content within tear-off shingles (at least 20 percent), about 32,000 tons per year of binder (virgin liquid asphalt oil) would be conserved by recycling shingles into HMA pavement.

Rotochopper Inc. is the equipment manufacturer that sold its “RG1” grinder to Dem-Con.  “We have seen numerous successful tear-off shingles recycling businesses around the United States and Canada” says Vince Hundt, vice president of Rotochopper.  “Our RG1 grinder can produce a high-quality, finely ground RAS product in one pass.  Recyclers like Dem-Con will be able to sell a valuable recycled product to HMA producers”.

Plehal Blacktopping installed the asphalt pavement at Dem-Con’s Shakopee plant.

“Our paving crew didn’t notice any difference,” says Jack Van Remortel, president of Plehal Black-topping. “The bituminous mixture was installed using normal equipment and procedures.”

MnDOT has been a leader in the country among other state departments of transportation when it adopted an earlier specification in 1996 for the use of manufacturers’ shingle scrap for use in HMA.

This “new” shingle scrap comes from the three shingle manufacturers located in Minnesota.  Since then, MnDOT has participated in five demonstrations of road construction projects that have successfully incorporated tear-off or “used” shingles into HMA pavements.

MnDOT is currently considering how best to write requirements for an updated new materials specification that would allow tear-off shingles in HMA.

Source: Asphalt Contractor December 2008, Paving Innovations