Consequently, TxDOT has begun evaluating the feasibility of incorporating recycled materials into various concrete construction applications. Previously, researchers have successfully used fly ash, silica fume, and other inorganic waste materials in concrete. Plastics are derived from oil and gas, so recycling existing plastic conserves an important natural, nonrenewable resource.
Car tires present a complex disposal problem.
Tires are designed to be indestructible, and they don't break down in landfills. They are also difficult to recycle. Industry figures show approximately 2 billion scrap tires are currently stockpiled in the U.S., with as many as 240 million additional scrap tires generated each year. The crumb rubber studied in this project is produced when tires are reduced to small particles through mechanical processes. RAP is gaining popularity in road construction.