Crumb rubber, also referred to as ground rubber, asphalt rubber or size-reduced rubber, is most commonly derived from recycled automobile and truck tires. During the tire recycling process, all non-rubber materials such as dirt, bead wire and fluff, are removed. The remaining scraps of rubber are reduced to a more manageable size, usually by a mechanical grinder. Continued processing reduces the size of the rough grind into crumb rubber particles, which have various classifications, based on crumb rubber particle size and color.
The trend towards use of recycled materials has increased the demand for crumb rubber. The manufacture of asphalt rubber is the largest single application of crumb rubber, consuming an estimated 220 million pounds, or approximately 12 million tires annually. Crumb rubber can be blended with asphalt to improve the properties of the asphalt used in highway construction.1
Crumb rubber has other applications, including ground cover under playground equipment, running track material, and as a soil additive in sports and playing fields. Other uses for crumb rubber include molded rubber products (e.g., carpet underlay, dock bumpers, patio decks, railroad crossing blocks and movable speed bumps); new tire manufacturing; automotive parts such as brake pads and shoes; as an additive to injection molded and extruded plastics and as agricultural and horticultural applications/soil amendments.2