shreds often can lead to prolonged life of roads, and the implementation is usually
very cost effective (Clark, Meardon, & Russell, 1993).
The tyre shreds can be processed to even finer levels. This product, called
crumb rubber, is almost entirely devoid of contaminant wire and material.
Unfortunately the methods for producing crumb rubber are complex and expensive.
One method is to cryogenically freeze the rubber shreds and mechanically pound
them to break them into finer pieces, removing the fibers and metal wire thereafter
(Brown, 2002). Other methods exist for creating crumb rubber without the need for
cryogenic temperatures, but it is unknown if these are cost effective (Anthony, 1999).
This rubber product can be processed into such items as shoe soles, industrial mats,
and playground tiles (Steuteville, 1995).
2.2.2 Uses for Whole Tyres
Tyres do not need to be shredded to find use. Whole tyres have found a variety
of uses in civil engineering projects as well (Hylands & Shulman, 2003). When
strategically placed on hillsides or beaches, tyres can help fight erosion. Though
unsightly, it may be the best option for areas with little capital to spend processing the
tyres. Boats can use tyres as bumpers. A stack of tyres covered in fiberglass has been
found to make an effective highway barrier as well (Clark, Meardon, & Russell,
If tyres are linked together and placed on the ocean floor they can form an
artificial reef (Rowe, 2002). In the past, artificial reef projects using waste tyres were
prone to problems of tyres washing ashore in large numbers. This is often either due
to strong ocean currents or poor reef construction. Care must be taken to ensure the
binding material that holds the tyres can withstand the salty ocean environment;