Markets for recycled tires are more diverse and sophisticated than ever, with rubber-modified asphalt an especially promising technology for the future, according to Dick Gust, director of government affairs and president of national account sales for Liberty Tire Recycling.
But effective management of end-of-life tires, whether by government or industry, still plays a major role in ensuring that scrap tires get to useful end markets, said Glenn R. Maidment, president of the Rubber Association of Canada.
Gust and Maidment were among the speakers at the 30th annual Clemson University Tire Industry Conference, held at Hilton Head, S.C., April 23-25.
The tire recycling market in 2013 was strong, but it still is not quite where the tire industry would like it to be, Gust said.
More than 302 million new tires of all sorts were shipped in the U.S. in 2013, he said. Meanwhile, industry experts indicate a tire recycling rate last year of between 85 and 90 percent of all scrap tires generated.
“The industry is trying to improve that percentage,” Gust said. “Off-the-road tires represent the new frontier in tire recycling.”
Tire-derived fuel and civil engineering applications long have been prominent in tire recycling, according to Gust. But new technologies in ground rubber—such as rubber mulch, playgrounds, athletic fields and rubberized asphalt—are threatening to surpass the more traditional markets, he said.
“Today's technologies clean, process and convert tire chips into a unique rubber mulch that is non-allergenic and harmless to plants, pets and children,” Gust said.
Synthetic turf for athletic fields has a sustainable layer of crumb rubber that ensures its stability and cushioning capabilities, he said. But the most promising crumb rubber technology, he said, is rubber-modified asphalt.
“Innovators of the industry are converting scrap tires into rubberized asphalt highways,” he said. “These highways ride quieter, last longer and use significantly less paving materials than traditional asphalt.”
Rubberized asphalt uses a lot of scrap tires and uses them well, Gust said. One mile of a four-lane highway paved with rubberized asphalt will use up to 80 tons of crumb rubber, equivalent to about 8,000 scrap tires, he said.