The Tyre:.Where does it Come From and Where does it Go?

WME Magazine

A standard car tyre consists of three components: the carcass, belts and tread. The carcass - in essence the main body of the tyre - is made of a synthetic rubber sheet with radial polyester or rayon cords running through it for strength.
The belts are rubber sheets embedded with brass-coated steel wire used to give additional strength and support under the tread, which is the layer of grooved rubber that makes contact with the road. The synthetic rubber and polyester are produced from fossil fuels, the steel is mined from iron ore and the_ rayon is a form of cellulose produced from wood pulp. These components are assembled and 'vulcanised' - pressed at around 198°C to make the sandwich of rubber tough and resilient to heat.
Creation of a standard family car tyre uses 27 kg of raw material and 584 L of water. In the process, it produces 4.4 kg of waste and 13.5 kg of materials extracted but not used. Australia disposes of 20 million car tyres annually. Once the tread has worn away - after an average life of 50,000 km - tyres in Australia go to one of four destinations: landfill, incineration, retreading or recycling.
Around 57 per cent of Australian tyres go to landfill each year but this is by far the worst option environmentally. Without sunlight a tyre takes up to 30,000 years to degrade, taking up valuable space, providing havens for vermin and mosquitoes, and posing a fire hazard. A further 13 per cent are dumped.
Since tyres are essentially just processed hydrocarbons, they burn readily. The calorific value of a tyr8is 34 MJ/kg, better than Australian black coal at 28 MJ/kg. In Victoria tyres are used to power a cement factory. The drawback is that only a small proportion of the energy taken to create the tyre is recovered. Incomplete combustion can also occur if the tyres are not incinerated at sufficiently high temperatures, creating gases such as carbon monoxide.
Retreading extends the life of a tyre, so it seems like the best end-of-life use. However, the jury is still out on this one. While retreads do postpone the need for a new tyre, they have a higher rolling resistance than a new tyre and as most of a tyre's impacts come about as a function of this resistance, some studies have shown the environmental benefits of avoided resource use are outweighed by running an inefficient tyre. Others say the scale tips about even.
Belgian tyre researcher BLIC says the best use for a used tyre is to pulverize it into crumbs and reuse it in another guise. In both the Eco-Indicator 99 and Environmental Policy Strategies (EPS) method of lifecycle analysis, recycling is good for the environment. Crumbed tyres make good road bases and playground and sporting surfaces, and can be used in construction as a replacement for gravel or, in some. cases, processed into building materials.

Fossil fuels used to make 1		2 mined for steel.		3 used to produce rayon.
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Materials are assembled.

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Materials are 4 to increase strength.

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Average tyre used for 5 then disposed of.

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Landfill = least attractive environmental 6		Incineration = recovers low percentage of 7		Retreading = environmental benefits may be 8		9 = best choice.