Nebraska Department of Environmental Quality
Winter 2002/2003
Innovative Project Recycles Tires, Improves Road Surface
A mixture of asphalt and rubber from recycled tires being applied to Interstate 80 between Gibbon and Shelton.A pilot project completed in September on Interstate 80 demonstrates an innovative use for scrap tires. Over 47,000 scrap tires have been blended into an asphalt mix in the resurfacing of seven miles of I-80 between Gibbon and Shelton.
The Nebraska Department of Environmental Quality awarded a grant to the Nebraska Department of Roads to conduct this pilot project to test an asphalt rubber mixture. The mixture includes scrap tires generated in Nebraska which have been ground into fine particles.

The grant compensates the Department of Roads for the extra costs that the agency is incurring to develop and test this new mixture, when compared to the price of simply laying traditional asphalt, said Steve Danahy, Supervisor of DEQ’s Waste Planning and Aid Unit. DEQ and Roads officials expect that the costs incurred with rubberized asphalt will come down as more projects are pursued.

“We feel it’s an effective method of dealing with scrap tires, because it not only consumes a large number of tires, but there is a definite and measurable benefit when compared to conventional asphalt,” Danahy said. “Rubberized asphalt not only recycles tires but improves roads.”

It is expected that this rubber asphalt mixture will extend the life of the asphalt overlay, and will be less prone to cracking. And, if a similar project completed last year on Highway 2 in Lincoln is any indication, drivers will find that the new portion of roadway will provide a quieter, smoother ride for their vehicles.

Robert Rea of the Department of Roads said both the I-80 and Highway 2 projects have demonstrated that there are no “laydown problems” with this rubberized mixture – that is, this mixture is as easy for road crews to apply as conventional asphalt. Rea said that they are continuing to examine all aspects of the mixture to develop the optimal blend for Nebraska. One aspect being examined is whether to grind the rubber into even finer granules, to ensure maximum durability in Nebraska’s “wet and nasty winters.”

Ultimately, the rubberized asphalt mix could become cost competitive to conventional mixes, Rea said. He said that the first step is to get greater involvement with Nebraska contractors in this innovative approach. In the initial pilot projects, the Roads department brought in contractors from Arizona who had experience with the rubber blending process. This contributed to higher costs. However, the actual mix design, production and paving of the new mixture was performed by a local contractor, Dobson Bros. Construction Company of Lincoln. Through these pilot projects, Nebraska has been acquiring considerable practical knowledge about the process, and Rea said he hopes the state will soon undertake new projects that will include the rubber blending process with local contractors.

Future projects could also help to reduce a serious scrap tire waste problem in Nebraska, Danahy said. Nebraskans generate the equivalent of about 3.5 million scrap passenger tires every year, and tires are banned from being disposed of in landfills. Although there are other innovative on-going scrap tire projects funded by the state, there are far more scrap tires being generated than recycled annually in Nebraska.

The end result is that the majority of Nebraska’s scrap tires are being exported out of the state for disposal – which is both expensive and a waste of resources. Conceivably, road resurfacing projects could greatly reduce this scrap tire problem.

And, the recycling benefits don’t have to stop there, Danahy said. “Rubberized asphalt itself can easily be recycled again when the road is eventually resurfaced.”

Article by Brian McManus

Nebraska Department of Environmental Quality
1200 "N" Street, Suite 400
P.O. Box 98922
Lincoln, Nebraska 68509
(402) 471-2186