The benefit of similar practices for recycling scrap tires in different regions of the world is uniformity and a standard of quality for the end products. If the various components of tires (steel, nylon, and rubber mix (natural and synthetic rubber and silica)) can be recovered, then the quality of the output can be checked through testing coupons as per ASTM (the American Society of Testing and Materials).

Pyrolysis, a technique that heats whole or shredded tires in a reactor vessel containing an oxygen-free atmosphere, has been introduced in the U.S. Rubber is softened and rubber polymers are broken down into smaller molecules that vaporize and then exit from the reactor. The minerals in the tire, about 40% by weight, are removed as solid ashes. When performed properly, tire pyrolysis is clean and produces little emissions or waste. However, concerns about air pollution due to incomplete combustion (as is the case with tire fires) have been documented.

The other emerging alternative is using chemistry to break down molecular bonds. The devulcanized rubber is then mixed with non-recycled rubber to mold new parts.

Whole tires can be used in gardens and playgrounds, around boat docks, as anti-collision stoppers, but these make for very limited applications. Stamping and cutting tires are used in emerging countries for some apparel products such as sandals. Shredded tires can also be used in civil engineering applications such as sub-grade fill and embankments, back-fill for walls and bridge abutments, sub-grade insulation for roads, landfill projects, and septic system drain fields. Artificial reefs are built using tires that are bonded together in groups, though there is some controversy on how effective tires are as an artificial reef system. An example of that is the Osborne Reef Project which became an environmental nightmare that cost millions of dollars to rectify. Using granulators, steel and nylon can be removed from rubber nuggets with further size reductions. Depending on the cleanness of the breakdown, steel and nylon can be recycled 100%. Crumb rubber can be used for many purposes, such as bedding for animals, mulch, landscapes and underlays, etc.

Further reductions in size result in rubber powder that can be used to surface sport tracks and ultimately as fillers (replacing carbon black for example). Post-recycling applications should be studied–for example, what happens when using rubber shreds instead of gravel for resurfacing a road (collecting tires is much easier than rubber nuggets that can be further spread with rains and winds)? An ultimate solution is to devulcanize the rubber so it can be re-molded, even if mixed with new non-recycled rubber.

Pneumatic tires are manufactured in about 450 tire factories around the world. Tire production starts with bulk raw materials such as rubber, carbon black, and chemicals, and produces numerous specialized components that are assembled and cured. Many kinds of rubber are used, the most common being styrene-butadiene copolymer (SBR).

In 2019, $258 billion worth of tires were sold worldwide. Over three billion tires are manufactured annually, making the tire industry a major consumer of rubber. It, therefore, makes sense to use recycled rubber in making new tires even if tires are highly critical components of vehicles. Essentially, two options are possible. First, using fine powder rubber from recycling tires as fillers in compounds for new tires, and second, devulcanizing crumb rubber and mixing it with non-recycled rubber for manufacturing tires.

Every ounce of recycled material reduces the need for the equivalent of new material eith the related discharge of greenhouse gases and the usage of electricity. The paradigm shift is in devulcanizing the ground rubber from recycling tires.