Rubberized Asphalt Concrete (RAC)
Finding Alternative Beneficial Uses for Old Wasted Tires
Aug 3, 2008
The State of California through its Integrated Waste Management Board (CIWMB), like a number of other states, is actively diverting used tires from community landfills and putting them to work on public highways by blending the rubber from old tires with asphalt. Waste tires can pose health hazards by sheltering mosquitoes and rodents, accumulations of old tires are a fire hazard, and take up valuable space in landfills.
In a recent press release announcing the release of grant funds to California communities, Board Chair Margo Reid Brown states, “Disposing of tires in landfills and stockpiles creates a number of environmental and health hazards. Finding alternative uses such as RAC (Rubberized Asphalt Concrete) for waste tires is another example of Californians taking steps to protect the health of our people and our environment.”
What is Rubberized Asphalt Concrete (RAC)?
The use of waste tires in the production of asphalt started in the late 1970's in Phoenix, Arizona. Tire recyclers separate the rubber from the tire's fabric and steel components and grind it up into what is called "crumb rubber". Blending the crumb rubber with conventional asphalt produces Rubberized Asphalt Concrete or RAC. Up to 2,000 used tires can be used for every mile of road lane that is paved.
Benefits of Using RAC
In addition to providing an avenue for recycling waste tires, the use of RAC has other important benefits:
- Using RAC clearly reduces road noise by as much as 85%
- Applying a two-inch layer overlay of RAC can save $50,000 per lane mile compared to using four inches of conventional asphalt in the same application
- An overlay of RAC can prevent cracks in underlying pavements from reflecting through to the surface of the new paving
- RAC retains its original color better than conventional asphalt and markings remain more visible
- Using RAC saves on maintenance costs, a properly designed application can last 50% longer than use of standard asphalt
- RAC provides better traction and can reduce traffic accidents in poor weather
There are some limitations in using RAC, for instance it cannot be applied in very hot or cold weather. For the most part, the development of rubberized asphalt concrete has been a success story. Officials in California estimate that encouraging the use of RAC through state grants has resulted in at least 15 million waste tires being recycled. Funding comes through a recycling fee assessed during the purchase of new tires. Additional information concerning RAC can be found at the Arizona Department of Transportation website.
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