The Use of Tire-Derived Aggregate in Road Construction Applications

The use of shredded scrap tires (also referred to as tire-derived aggregate: TDA) in civil engineering applications has three major advantages: shredded tires (TDA) have engineering properties that are beneficial to civil engineers; TDA is often the lowest cost material that can provide the engineering properties sought and TDA can use large-scale numbers of scrap tires. The use of TDA could provide a much-needed, large-scale market where few other viable end uses for scrap tires exist. Tire-derived aggregate can be used in a wide range of highway uses and is currently one of the three major markets for scrap tires. In 2007, an estimated 561.6 thousand tons of TDA was used in this market; about 12 percent of the total number of tires that went to an end use market (RMA, 2009). Furthermore, tire shreds have been shown to have a negligible impact on groundwater quality. This paper will present the special properties of tire shreds that drive engineering applications. Examples will be given of projects where tire shreds were used as lightweight fill for highway embankment construction, bridge abutment backfill and as a thermal insulation to limit frost penetration beneath roads. The guidelines to limit heating and water quality effects of tire shreds will be discussed. From the information presented below, it will be clear that the use of TDA can benefit civil engineering projects and can play a key role in putting this nation’s scrap tires to a productive reuse.