Crumb rubber is used in a variety of products, including rubberized asphalt for paving projects, hoses, auto parts, flooring and other applications, including some designed into new tires.
"Crumb rubber is something that hopefully will take over for TDF in the near future," Gust said.
The steel wire material is high carbon steel that is sent to smelters for processing and reused in such products as home appliances, automotive manufacturing, building construction, and water and fuel tanks, according to the TIA CEO.
He specifically noted that rubberized asphalt has made improvements in technology over the past few decades. There are new methods for combining ground tire rubber with asphalt; the cost of modified asphalt mixes with rubber have significantly reduced in cost; and it allows for the use of thinner, low-cost rubber pavements for light duty roads.
And the "dry process" rubber asphalt handles like regular hot mix asphalt, Gust said, but the modified pavement is more resistant to rutting and cracking.
"Rubber modified asphalt can be recycled back into another road. So it truly is a sustainable product," he said.
There also are emerging technologies that are becoming commercialized that will improve the quality and economics of recovering the raw materials in the tire. "When this happens, current recycled rubber end uses benefit, and the use of recycled material in tire production and other products will increase," Gust aid.
These include micronization, where liquid nitrogen freezes rubber to its "embrittlement temperature" and mechanical shearing is used to convert the particles to powder. In addition, devulcanization breaks the sulfur-to-sulfur and sulfur-to-carbon bonds between the polymer chains, leaving rubber particles.
Pyrolysis, or heating whole or shredded tires, is bringing companies in the business to open the door for easier carbon black recycling, with the benefit of steel and oil production, he said.
"The days of tires becoming an environmental problem are coming to an end," Gust said. "Better solutions are being developed to capture the high-quality steel and to recover the valuable raw materials designed into the tire. Instead of tire dumps and landfills, we see roads, playgrounds, rubber products, sporting fields and, yes, materials designed into new tires."