Tire recycling

Of the tires that were scrapped, 43% were burnt as tire-derived fuel, with cement manufacturing the largest user, another 25% were used to make ground rubber, 8% were used in civil engineering projects, 17% were disposed of in landfills and 8% had other uses.

Tire fires can easily occur, burning for long periods, up to a month and also creating substantial pollution in the air and ground.

An additional health risk, tire piles provide harborage for vermin and a breeding ground for mosquitoes that may carry diseases.

Tire storage and recycling are sometimes linked with illegal activities and lack of environmental awareness.

[16] Tires have also been cut up and used in garden beds as bark mulch to hold in the water and to prevent weeds from growing.

In either case, the high gas temperatures (1000–1200 °C) cause almost instantaneous, complete and smokeless combustion of the tire.

Alternatively, tires are chopped into 5–10 mm chips, in which form they can be injected into a precalciner combustion chamber.

These vapors can be burned directly to produce power or condensed into an oily type liquid, generally used as a fuel.

[22] The properties of the gas, liquid, and solid output are determined by the type of feed-stock used and the process conditions.

The remaining solid material, often referred to as "char", has had little or no value other than possibly as a low grade carbon fuel.

Char is the destroyed remains of the original carbon black used to reinforce and provide abrasion resistance to the tire.

This high volume component of tire pyrolysis is a major impediment, although this theme continues to be a source of innovation.

The drill forces athletes to lift their feet above the ground higher than normal to avoid tripping.

[26] Re-purposed tires can also be harnessed as an affordable alternative building material used in the framework of rammed Earth thermal mass dwellings.

[28] Rows of stacks of tires are often used as barriers in motor racing circuits as a method of dissipating kinetic energy over a longer period of time during a crash, comparatively to striking a less malleable material such as a concrete or steel wall.

They are more quiet than most roofs, hail resistant, and a high wind rating if there is a tongue and groove fitting at the front edge of the rubber shingle design.

[31][32] Due to their heavy metal and other pollutant content, tires pose a risk for the leaching of toxins into the groundwater when placed in wet soils [citation needed].