Tire-Derived Aggregate (TDA)
Tire derived aggregate (TDA) is made from shredded tires and is used for a wide range of public works projects and other civil engineering applications. These include slope stabilization, retaining wall backfill, lightweight embankment fill, vibration mitigation, various landfill applications, and more. For more information about applications of TDA look at Civil Engineering Applications Using Tire-Derived Aggregate (TDA) or Continuing Education and University Curricula of Rubberized Asphalt Concrete and Civil Engineering Application of Waste Tires which is also available in Spanish.
Tire-derived aggregate provides the second largest reuse of scrap tires in the United States. California currently has the potential of using several million tires per year and increased use is anticipated in the future. TDA plays a major role in providing a solution to diverting California’s scrap tires from landfills and illegal tire piles.
The Department of Resources Recycling and Recovery (CalRecycle) encourages the use of TDA in California through several programs:
- Technical Assistance. CalRecycle provides engineering and technical assistance to local jurisdictions for education, design, and construction oversight on TDA projects in California.
- Green Roads. CalRecycle's Green Roads website promotes waste tires as a valuable resource and environmentally sound solution to solve engineering problems.
CalRecycle has a TDA grant program to provide assistance to local governments to fund TDA projects..
Note: In January 2010, the functions and responsibilities of the California Integrated Waste Management Board (CIWMB) were transferred to the new Department of Resources Recycling and Recovery or CalRecycle. This change was mandated by Senate Bill 63 and included merging the former CIWMB with the Department of Conservation’s Division of Recycling. SB 63 also called for establishing the newly formed CalRecycle within the California Natural Resources Agency; CIWMB had previously been a part of the California Environmental Protection Agency.
For historical purposes, the TDA website retains some references to our previous organizational identify to indicate which actions and activities, undertaken prior to January 2010, were done so by the CIWMB. More information about the new CalRecycle is available on our About Us page.