Recycled tire rubber

Schnormeier, R. Recycled Tire Rubber in Asphalt, 71st Annual Meeting Transportation Research Board Washington, DC, 1992. 

Schnormeier R (1992) Recycled tire rubber in asphalt. Presented at the 71st Annual Meeting of the Transportation Research Board, Washington, DC, p 537... 

Until recently, it was generally understood that only a few percent of ground rubber can be used in new tires. Scrap Tire Management Council reports that 5% of recycled tire rubber is used in an original equipment tire for the Ford Windstar. Although no other information on the amount of devulcanized rubber used in new tires is available in open literature, a possibility exists for the use up to 10 wt.% of recycled tire rubber in new tire compounds (Myhre and MacKillop, 2002). It was reported that actual road tests of buck tire containing 10 wt.% of the devulcanized rubber in the tread exhibited tread wear behavior almost equal to that for standard type with the new rubber compound (Fukumori et al., 2002). The increase in the amount of recycled mbber in tires is growing but it is likely that results will not be available for a number of years. 

Nehdi, M., Khan, A., 2004. Protective system for buried infrastructure using recycled tire rubber-filled cement mortars. Am. Concr. Inst. Spec. Publ. 219, 99 (in book Recycling Concrete and Other Materials for Sustainable Development). 

PE/PP Recycled tire rubber Thermoplastic vulcanizate described (Syman-T NRI Industries) based on recycled tire rubber blend with PE/PP mixtures 169... 

S. Bandyopadhyay, S. Dasgupta, N. Mandal, S.L. Agrawal, S.K. Mandot, R. Mukhopadhyay, A.S. Deuri, and S.C. Ameta, Use of recycled tire material in natural rubber based tire tread cap compound Part I (with ground cmmh rubber). Progress in Rubber, Plastics and Recycling Technology, 21(4), 299, 2005. 

There is a need to continue to perform research on methods of recycling tires, such as the use of crumb rubber in rubber products and plastics. Existing research on rubberized asphalt should be summarized, and a decision made regarding its feasibility for more widespread use, or if there are still technical or economic questions, determining exactly what additional research is needed to answer these questions, and then perform this research. States and Federal government, and environmental and transportation agencies, should coordinate research efforts so that fewer, more comprehensive research projects (particularly related to rubberized asphalt) can be performed. 

Recycling rubber from tires for use in asphalt pavements is a promising technology. Asphalt pavements incorporating tire rubber are claimed to have twice the lifetime of ordinary asphalt, but they can cost twice as much. Pavements with crumb rubber additives consume over one million tires per year now, and both asphalt-rubber and rubber modified asphalt concrete have considerable potential for expansion. If Federal, state, and local governments promote much broader use and demonstration of this technology, perhaps the technical issues will be resolved and usage will expand. 

Tires, Rubber—Recycling. 2. Recycling (Waste, etc.)—United States. 3. Waste products as fuel—United States. I. United States. Office of Solid Waste. II. Clark, Charlotte. 

The combustibility tests on small samples associated a classification of IV (moderate combustible) to the recycled tire and a value V (low combustible) to the dominantly green EPDM material. The EPDM material embodied some recycled rubber due to such inclusions, the combustibility class was reduced. 

Recycle Today there is a great emphasis on devulcanization methods to recycle the rubber in tires and other rubber products. Some of these new devulcanization methods use supercritical fluid technology, ultrasonic techniques, microwave energy, and biological modification.f These methods are explained in detail in the entry, which deals primarily with devulcanization. 

Recycle Research Institute, 2002 Scrap Tire Rubber Users Directory, 2002. 

The process is being used on a commercial scale on Hokkaido, Japan, but appears to be uneconomical in the United States. (Mixtures of scrap tires with waste plastics have also been pyrolyzed.247) It appears to be cheaper in the United States to burn the tires for energy at lime kilns, paper mills, and such.248 The sulfur in the tires must be trapped by the lime or by other means. The combustion conditions must be such that the usual thick black smoke of burning rubber is not present. Recycling the rubber in the tires to more items of rubber would be preferable to just burning them as fuel. The real key to fewer tires to recycle is to devise better land use systems that require fewer automobiles (see Chap. 15). 

There are various ways to recycle waste tire rubber. The first approach consists of reducing the tire rubber into scrap rubber. Sometimes, before retreading old tires with new rubber, the part of the tire that needs extracting is converted into scrap. 

Mechanical properties of asphalt can be improved [16] by modification with some polymers, especially stirene-butadiene-stirene (SBS) tri-block copolymer. SBS/ asphalt blends are prepared via dynamic vulcanization. Recycled tire crumb rubber is incorporated as a major component in its multi-layer construction [17] for a stadium field-turf. 

On the other hand, the mechanical properties of thermoplastic vulcanizates containing ground tire rubber have been investigated with the aim of increasing use of recycled rubber. The compositions tested included passenger car combined with EPDM, SBR rubber, isoprene rubber, and butadiene rubber. It was found that the particle size of the ground tire rubber had small effect on mechanical properties, but that the choice of the sulfur accelerator was significant [26]. 

Recycling waste tire rubber is such large a problem that it could be covered only by a book entirely devoted to the subject. Eollowing the scope of the present book concerned with the cure of rubbers, only general considerations have been made by giving attention to applications employing, to some extent, the cure process. 

Moore M. 2002. Better tires make recycling complex. Rubber and Plastics News. 24 5. 

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