otherwise the material will corrode and release the tyres creating an environmental
disaster. If done properly tyre reefs can form a great natural habitat for fish and other
Whole tyres can also be burned for fuel directly without the need for
shredding or processing, though this requires existing kilns to be modified (Clark,
Meardon, & Russell, 1993). These modifications to accommodate whole tyres can be
expensive and problematic due to the accumulation of incombustible products. If the
whole tyres are burned the ash contains lots of carbon material and steel slag which
can also be used in civil engineering applications such as mixing with concrete.
2.2.3 Rubber Asphalt
Rubber asphalt is an interesting application of tyre waste. Used to coat the top
layer of roads, rubberized asphalt contains at least 15% reclaimed tyre rubber by
weight. The rest of the asphalt is composed of regular asphalt cement and additives
(Rubber Pavements Association, 1998).
Besides the great benefit of recycling tyres, rubberized asphalt has plenty of
advantages over regular asphalt. These include reduced pavement thickness,
absorption of traffic noise (up to 85% has been noted), and longer road life. About
2,000 tyres are recycled per “lane mile”. The road life can be dramatically increased
which can help save costs in the long run. Furthermore, rubberized asphalt can be
recycled, used in diverse climates, and the emissions at the processing plant are
similar to that of regular asphalt (Rubber Pavements Association, 1998).
There are initial costs associated with rubberized asphalt. The processing
equipment is a significant investment, though once set up regular equipment can be
used to apply the asphalt to the road. Processing the waste tyres to create a fine