Glossary of Terms and Acronyms Tire Chip A term used to define the approximate size of a shredded tire once it is shredded and screened or classified to create a consistent size. Typically, this term is used in conjunction with a size specification required by the end user. Examples are: 6”x6”/150 mm x 150 mm, 4” x 4”/100mm x 100mm, 2” x 2”/50 mm x 50mm, or 1”x 1”/25 mm x 25 mm. Tire Chips are generally smaller than twelve inches in length and most of the exposed metal is removed. Actual dimensions should be specified by the design engineer or design professional based on the specific performance criteria needed for the project. Tire Composition The weight percent of the respective tire components can be broken down for average passenger and truck/ bus original equipment tires. Since each manufacturer may have different design characteristics, the following tire compositions are offered for the average tire: Tire Composition Passenger/Light Truck Truck/Bus Natural Rubber 19% 34% Synthetic Rubber 24% 11% Compounding Additives 40% 34% Non- Rubber Steel 13% 21% Textile 4% 0% Note: Compounding additives include antioxidants, antiozonants, curing systems (sulfur/zinc oxide), carbon black, silica, processing oils. Tire-Derived Aggregate (TDA) Tire-derived material used to replace conventional aggregates like rock in civil engineering applications. The TDA consists of scrap tires cut into pieces that have a basic geo-metrical shape and are “generally between 0.5 inches (12 mm) and 12 inches (305 mm) in size and are intended for use in civil engineering applications” (ASTM D6270). There are two types of TDA: Type A with a maximum size of 3 inches (75 mm) and Type B with a maximum size of 12 inches (305 mm). Properties of Tire Derived Aggregate (TDA): • Capillary Break: TDA can be the material between the parallel layers stopping capillary action. The high porosity of TDA and its non-absorptive qualities prevent water from wicking toward the surface, eliminating frost heaving. • Lightweight TDA Definition: Tire Derived Aggregate is approximately 1/3 weight of soils (600 pounds per loose volume cubic yard). 1 ton = 1.67 cubic yards (in place). In place density = 45-50 pounds per cubic foot. • High Permeability TDA Definition: Drains ten times better than soil. TDA is free draining and has higher permeability than typical drainage rock. (> 1 to 30 cm/sec.)
RkJQdWJsaXNoZXIy NzU3OTQ=