Tires are made of many materials, and their process of development and production is extremely complex; for they are developed to be gifted with great resistance and durability, and this is precisely the origin from which problems arise when it comes to recycling.
From the point of view of materials they are made of, a tire is a mixture of synthetic and natural rubber, to which a great variety of specific substances are added, in order to ensure functioning, durability and safety.
These include mineral oil, infillings such as strengtheners (carbon black and silica) and vulcanizing agents (sulfur) which act as catalysts to accelerate the vulcanization process. These features contribute in many ways to permitting the development of a great variety of uses and final destinations, which come from recycling.
Among these applications we have: Shore protection, erosion barriers, artificial reefs, breakwaters, protection against avalanches, slope stabilization, road embankments, construction infilling, noise barrier and insulation. Today this market is made of individual projects and therefore they are small scale.
Whole tires are cut into pieces mechanically, ranging in size between 25 and 300 mm.
Rubber pavements are used as bottom layer for roads and railways, replacing drainage material made of sand and gravel.
They are also used as infill in constructions, such as foundations and retaining walls, infilling for walls and bridges, and foundation insulation for roads.
After removing the steel and the textile component, the remaining rubber is reduced to rubber granules.
Among uses for it we have rubber molded products, such as tires for carts, bins, trolleys and lawn mowers, and street furniture and signage.
The granulates and rubber powder can also be found on playground surfaces, sports courts and athletic tracks, safety flooring for schools and stables, tiles for patios and pools, as well as roofing.
Rubber granules are widely used in the construction of artificial grass pitches for football or rugby, acting as infill material.
Asphalt gives good use to elasticity and noise absorption property of rubber. Although increasing the useful life of the road surface, rubber reduces noise pollution, and increases safety in case it is wet … it is still relatively little used (a few hundred kilometers of road in total) despite its multiple advantages.