Publication Number: FHWA-RD-01-060
Date: January 2001

Highway Materials Recycling: Partnering for Sustainability

Recent European and U.S. advances in recycling highway materials, as well as opportunities for State highway agencies to partner with others on recycled materials use, were the driving themes for participants at "Partnerships for Sustainability: A New Approach to Highway Materials." Held on October 9-11, 2000, in Houston, Texas, the workshop attracted more than 100 attendees from both the public and private sectors. Workshop sponsors included the Texas Department of Transportation (DOT), University of New Hampshire Recycled Materials Resource Center, American Association of State Highway and Transportation Officials (AASHTO), Association of State and Territorial Solid Waste Management Officials, and the Federal Highway Administration (FHWA).

The workshop was an outgrowth of a 1999 scanning tour on recycled materials in European highway environments sponsored by FHWA's International Technology Scanning Program, which evaluates foreign technologies and innovations that could significantly benefit U.S. highway transportation systems. The US delegation visited Sweden, Denmark, Germany, the Netherlands, and France, meeting with representatives from transportation and environmental ministries, research organizations, contractors, and producers involved with recycled materials. All of the countries visited had policies promoting sustainability. For example, the Netherlands has a formal policy for sustainable development in highway construction that minimizes the use of natural materials and advocates the use of recycled ones. The government also provides clearly defined technical and environmental standards for recycling, which has contributed to high recycling rates for such materials as construction and demolition aggregates, blast furnace slags, recycled asphalt pavement, coal fly ash, and steel slags.

Most of the countries visited require that recycled materials meet the same specifications as natural materials and provide equal performance. A priority has been placed on carrying out performance-related tests, such as the cyclic load triaxial and gyratory compaction.

The European advances in recycling, including the Dutch sustainability model, were among the featured topics at the Houston workshop. Texas DOT's leadership in recycling highway materials was also highlighted. Since 1995, the DOT, in coordination with FHWA, the Texas Natural Resource Conservation Commission, and several Texas universities, has sponsored research projects investigating the use of a variety of recycled materials in road construction, including reclaimed asphalt pavement, concrete, fly ash, and plastics. Researchers have examined a number of potential applications for recycled materials, including use in roadway safety devices, embankments, and asphalt and concrete pavements. The agency has also reviewed its construction and maintenance specifications, eliminating all requirements for new materials and approving a number of specifications that specifically allow for the use of recycled materials.

With participants including highway agency staff, environmentalists, researchers, contractors, and suppliers, the workshop not only spotlighted technological advances but played an important role in building partnerships among all of those with a stake in highway recycling. "Some of the highway agency staff had never associated with the Federal and State environmental department staff and vice versa," says Jason Harrington of FHWA. "The workshop opened some eyes and some doors."

Recommendations made by workshop participants that are now being considered by the many stakeholders include establishing a National Steering Committee composed of Federal and State agencies and the private sector to further the concept of recycling in the highway environment and exploring legislation that might help promote recycled materials demonstration projects.

"We need to remove the stigma that recycled products and materials are inferior in performance," says Vince Schimmoller of FHWA and a coleader of the 1999 scanning tour. "We also need to encourage State and local governments to try new uses for recycled materials."

Another outgrowth of the workshop is a proposal that the AASHTO Subcommittee on Materials take a more aggressive approach in developing standards and guidelines for recycled materials use in highway construction. "AASHTO has made sustainability a priority and recycling is a big part of that," says Katherine Holtz of Texas DOT and cochair of the workshop.

For more information, contact Jason Harrington at 202-366-1576 (fax: 202-493-2070; email: k.jason.harrington@fhwa.dot.gov), or Taylor Eighmy at the Recycled Materials Resource Center, 603-862-1065 (fax: 603-862-3957; email: t.eighmy@rmrc.unh.edu). The workshop proceedings are expected to be available this month on the Web at www.rmrc.unh.edu. You can also find copies of the workshop program and presentations and the 1999 scanning tour report at www.rmrc.unh.edu/partner.asp.

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