New Uses for Old Tires

“Ever wonder about tires?” Keith Morrison of Dateline NBC asks over a visual of piles and piles of retired—pun intended—tires. “What happens to them when they get old and bald?” Mound after mound of unused tires as far as the eye can see are taking up acres and acres of land across the United States and they have been aptly labeled an environmental nightmare.

One tire can hold up to a gallon of oil, meaning, if a tire—or tires—catch fire, they burn extremely hot and for a long period of time…as in, months long until, oftentimes, the tire burns itself out. These tire fires are the cause of enormous environmental problems by releasing particulate black smoke into the air and runoff into streams and rivers. Unused tires are one of the leading solid waste problems in the country, and one solution quite literally lies in “where the rubber meets the road.”

The use of rubberized asphalt concrete (RAC) began in the 1930s, but it wasn’t until the 60s that a man by the name of Charles McDonald was instrumental in developing a wet process used in hot mix patching and surface treatments for road repair and maintenance. RAC is used mostly in The Sunbelt States, which are Florida, California, Arizona and Texas and is a mixture of asphalt cement, ground tire rubber and other additives.

RAC has a number of benefits, including improved durability, resistance to fatigue and reflective cracking, as well as lower life cycle costs. Although it costs more, only half the amount is needed and the road lasts twice as long. So in the end, it is cheaper and more cost effective. RAC looks virtually unused even after a decade of use, Executive Director of the Rubber Pavements Association (RPA) Mark Belshe says, “The pavement becomes stronger, inch for inch.”

The RPA is a non-profit association that emerged from the Asphalt Rubber Producers Group, which was founded in 1985. According to their website, the RPA is dedicated to the promotion of greater usage of high quality, cost effective asphalt pavements containing recycled scrap tire rubber. They are based in Arizona, where there is the largest and most widely used users of Asphalt-Rubber in the United States, alongside the other Sunbelt States. Belshe wants RAC’s usage to spread, laying no claim on the unpatented resource. “It’s an open technology,” he says, “We’ll give out the information to anyone who wants to learn about it.”

Belshe says that although RAC is widely used in the Sunbelt States, it is being used in colder states like Massachusetts, New Jersey and Ontario, Canada. He says the RPA is working to dispel the image of asphalt rubber only being viable in warmer climates, “We have been trying to point out that while we don’t recommend placing asphalt rubber mix in the cold, it performs very well in cold climates. It’s just a matter of best practices during construction and proper mix design.”

The RPA promotes awareness for road recycling and endorses a product that’s been around for decades now. Crumb rubber is not a new innovation, but Belshe says, “People are noticing that it’s cost effective.”
“It becomes a big CO2 savings,” Belshe points out, and adds, “Then, of course, there’s also the recycling aspect. Forty to fifty million tires have been recycled over the last ten years.” Some additional environmental benefits include landfill diversion, reduction in tire piles and noise abatement.

The RPA carries out its mission through technology transfer and maintains the largest library of Asphalt-Rubber research documents in the world. The main technology transfer activities include workshops, seminars and conferences, the publication of a quarterly newsletter and other informational materials. Since 1997, the association has conducted over 75 workshops for federal, state and local agencies, and also maintains a website that has been visited by thousands of individuals, agencies and countries.

The association’s membership is made up of “User” (contractors) and “Producer” (crumb rubber processors) members, as well as non-voting associate, affiliate, and individual classifications. A Board of Directors governs the association, which is funded by its member companies through assessments on the sale or purchase of crumb rubber used in asphalt applications.

For more information about the Rubber Pavements Association visit www.rubberpavements.org or call 480.517.9944.

Story by Jade Acadia