Applying sound recycling principles that protect the environment, the Federal Highway Administration's Recycling Team is helping industry reclaim materials like asphalt and concrete pavement, foundry sand, scrap tires, and roofing shingles into new highway materials while conserving the Nation's natural resources. This article describes how recycling highway construction materials can be a cost-saving measure, freeing funds for additional highway construction, rehabilitation, preservation, or maintenance. The author discusses cost savings, the use of reclaimed asphalt pavement (RAP), the use of recycled concrete aggregate (RCA), three versatile methods for in-place recycling of asphalt pavement [hot in-place recycling (HIR), cold in-place recycling (CIR), and full-depth recycling (FDR)], the use of commercial construction debris to create recycled concrete aggregate as a base for highway construction, the use of industrial by-products such as foundry sand, and the re-use of asphalt shingles and scrap tires. The author comments on the stigma that has been associated with recycling in the past and emphasizes the need for a focus on environmental stewardship, regardless of the materials used in construction. The author includes examples of real-life use of recycled materials in highway construction projects in Arizona, Florida, California, Texas, Ohio, and New York. One chart summarizes the use of recycled materials in U.S. highway construction, including blast furnace slag, concrete, coal bottom ash, asphalt, base coal fly ash, structural fill (cement production), foundry sands, flowable fill (asphalt), cement kiln dust, stabilizer bottom ash, nonferrous slags, steel slags, recycled asphalt pavement, and reclaimed concrete.
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