Scrap tires have many uses and multiply as the size of the particles decreases.
One of the key applications for scrap tires is soil preparation and improvement, said Valerie Shulman, secretary-general of the European Tyre Recyclers' Association.
When the chips are buried under the surface soil, they can act as a drainage layer, offering physical support for the ground above while allowing water to drain through the subsoil.
One advantage of the chips is their weight. They are much less dense than gravel, aggregate or other traditional materials and require lighter foundation work, Shulman said.
If the tires are ground to smaller sizes-around 1 millimeter-then the range of applications expands. Apart from the traditional markets such as sports surfaces and children's playgrounds, the granulate can be used in paving blocks, livestock mattresses, roofing materials and other large volume applications for covering significant areas of land with soft or forgiving surfaces.
All these applications, she said, are independent of the type of rubber used, and they can accept small shreds of steel cord within the material.
Most engineering companies insist on having material that offers consistent properties over time. This means processors have to deliver similar material from one year to the next in terms of particle size distribution and particle shape as well as chemical composition and dynamic performance of the particles.
While such specifications might be hard to meet, the rewards are greater than for simple shred or granulate, Shulman said.
The first priority for any entrepreneur thinking about establishing a tire recycling business is to ensure there are customers for the resulting materials, according to the secretary-general.
Many look at the economics and see that a shredding machine costs relatively little, and that companies will pay to have tires taken off their hands. They also can sell the resulting crumb for large amounts of money, she said. When they add up the figures, the business looks very attractive.
However, Shulman said, many people don't look at the costs of fire prevention or maintaining the shredder. Plus they tend to think that it will be easy to find buyers for their products. This is a very dangerous assumption, she said.