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| (Photo courtesy of NAPA) |
Highway contractors reuse millions of tons of asphalt pavement every year. Now, with the price of liquid asphalt up more than 40% on average over the past 12 months, they are looking to recycle more. Standing in their way are transportation engineers who believe that reclaimed asphalt pavement does not perform as well as virgin material.
“If you don’t solve this issue, we will charge you more,” says Dan Gallagher, vice president of operations at Thornton, Ill.-based Gallagher Asphalt Corp. Contractors in the Chicago area have more than 200,000 tons of reclaimed asphalt pavement (RAP) waiting to be used, he says, while the price of one ton of liquid asphalt in the region shot up from $170 to as high as $405 this year.
Asphalt, the syrupy glue that binds flexible pavement, makes up 5% on average of the total raw material in a road. In some regions of the U.S., high prices are making binder the largest cost input in a ton of mix. Asphalt concrete, on average, contains 13% RAP but can go as high as 50%. “We need to get the states to start trading in their old pavements,” says J. Don Brock, chairman and CEO of Astec Industries Inc., a bituminous equipment manufacturer in Chattanooga, Tenn.
Related Links: Highway engineers generally see RAP as friendly to the environment and the budget when used in small quantities. New methods for processing RAP gained momentum after oil prices spiked in the 1970s and early 1980s. Since then, however, the advent of volumetric “Superpave” mixes gave more credit to virgin materials and hindered RAP’s ability to compete. “If you put in more than 15% [RAP] you couldn’t run the specs,” says Brock.
Recycling experts claim that the equipment and methods are available to process large quantities of RAP with Superpave-like quality. Using “in-place” equipment, contractors can remove old pavement, mix it with new material, repave and reopen a road within hours.
As paving costs heat up, highway engineers are listening more to the recycling argument. “We are looking at ways to see if we can increase the RAP content,” says Ananth Prasad, chief engineer of Florida Dept. of Transportation. FDOT already has deferred $1 billion over the next three years due to high costs for asphalt, concrete, steel and earthwork.
Engineers like Prasad are targeting low-traffic roads for increased recycling but they approach Interstate specification changes with caution. For those roads, Superpave is the standard and “you don’t want to monkey with it too much,” he says. Fred Frecker, president of Flexible Pavements of Ohio, Columbus, says more research on higher RAP levels in Superpave is needed.
Most agree that more RAP content in roads would stretch budgets. Eric E. Harm, deputy director of Illinois DOT’s highway division, says that IDOT plans to develop new RAP guidelines that would become effective early next year. If they work, the agency could save up to 20% on its paving costs. “You’re talking about nickels and dimes, but it does add up,” Harm says.
Contractors, too, are eager to see states increase RAP allowances. If asphalt prices continue to rise, increased recycling could reward them with lower costs that yield larger profits.
