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Tire Recycling
Burning tires and other wastes in cement plants is NOT recycling. Combustion recovers only a portion of the energy contained in a tire; true recycling is much more energy efficient.
Tires are being recycled into running tracks, railroad ties, roofing shakes, parts on autos, sound barriers, playground safety mats, solid bicycle tires, tennis courts, compost bins, traffic delineators, slurry for levees and roads, flowable concrete, new tires, (current manufacturing processes allow up to 10% of a new tire to be made from recycled tires) and more:
Here in Belgrade, there is company named Big Sky Tire Feeders that makes livestock feeders out of used tractor tires. They hope to use 5,000 scrap tractor tires this year. See their website for more information.
Civil Engineering Applications
- Shredded tires are being used as lightweight fill which has improved permeability and greater insulating properties than traditional fill materials. Tire shreds can replace other conventional fill, such as expanded foam.
- Tire shreds can be used in septic tank leach fields, with an average four bedroom house using approximately 1,350 tires per system.
- Other civil engineering projects utilizing tire shreds and/or crumb rubber include overpass fill, levee slurry walls (mixed with concrete), frost barriers, retaining wall fill, roadway base fill, bridge abutment fill, highway edge drains, and leachate collection and methane gas collection systems in landfills.
Rubberized Asphalt Concrete
Rubberized asphalt concrete, or RAC, is made by grinding scrap tires into crumb rubber and blending the crumb with asphalt and aggregate. Los Angeles County has used rubberized pavement since 1993, with positive results. RAC roads are longer lasting, better riding, resistant to rutting and cracking; they reduce road noise by 50 to 80%, and are less expensive to build than traditional concrete highways. Surfacing roads with RAC uses up to 2,000 tires per lane mile. As with conventional asphalt, broken up rubber asphalt can be recycled into other road projects, so that scrap tires can be recycled over and over. See http://www.dot.ca.gov/ctnews/november00/ to read about California's use of tires in asphalt.
More Uses for Scrap Tires
- Waste tires can be compressed and bound into bales. Uses for tire bales include steambank erosion projects, feedlot drainage applications, livestock windbreak and corral applications, and firing range backstops.
- Crumb and granulated rubber is being recycled into molded rubber products.
Extending Tire Life
Tire manufacturers are producing long lived tires rated at 100,000 miles. Retreading extends tire life; truck and heavy equipment tires are best suited for retreading.
Energy Values
It takes approximately 55,000 BTU to produce a pound of rubber. Tires burned for fuel have an energy value of approximately 14,000 BTU per pound. It takes less than 1,000 BTU to convert a pound of waste tire rubber into good quality granulated or crumb rubber. Why 'recover' 14,000 BTU per pound of rubber in cement plants if we can preserve 54,000 BTU by recycling?
Considering the potential health and environmental hazards of tire burning and the low energy efficiency of incineration relative to recycling scrap tires into rubber products, burning tires in cement kilns is more than irresponsible, it's the worst thing to do with scrap tires.
To learn more, click on these links:
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