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Partnering plus "Three E's" equals recycling success
Jason Harrington, Recycling Technology Engineer, and Bill Bolles, Marketing Specialist, Federal Highway Administration, Washington, D.C.
We at the Federal Highway Administration (FHWA) know that in overseeing our nation's highways and bridges, we must also be stewards of the environment that is impacted by those highways. FHWA has been very active in promoting various industrial by-products to be used as alternative materials for highway and bridge construction. We want to keep spreading the word to the road construction community that the engineering feasibility and environmental soundness of using recycled materials has been confirmed in research, field studies, experimental projects and long-term performance testing and analysis. By correctly applying the principles of engineering, environment and economics—the three E's—an agency can help ensure the overall successful use of recycled materials in their programs.
Partnering makes recycling happen
Creating and using partnerships can make recycling programs more effective and efficient. Partnering helps different groups share information on the best recycling techniques for particular situations. And partners can carry this information, and the recycling message, to other parts. For instance, the Green Highways Partnership (GHP, www.greenhighways.org) has brought together many different groups—FHWA, the U.S. Environmental Protection Agency (EPA), other federal agencies, state transportation and environmental agencies, industry, trade associations, members of academia and contractors to encourage an environmentally friendly and systematic roadway planning, construction and maintenance program.
In August 2007, the FHWA, EPA and the Industrial Resources Council sponsored a workshop entitled "Conserving Resources and Building Infrastructure with Recycled Materials" in Baltimore, Maryland. Eighty transportation professionals attended this workshop to learn more about the use of recycled materials and identify ways to implement them into everyday highway construction practices.
During the workshop, representatives from Maryland reported that the state recycled more than one million tons of asphalt and concrete in 2005, as well as 145,000 tons of fly ash and more than 275,000 tons of construction debris. Virginia Department of Transportation (VDOT) reported that its transportation projects have included RCA, RAP, TDA, glass, granulated ground blast furnace slag, and fly ash. In Virginia, RCA has been used in embankments and as fill for roadway bases, and fly ash is regularly used as a cementitious material in Portland cement concrete, as a mineral filler in hot-mix asphalt (HMA), and in embankment construction.
Attendees from Pennsylvania reported during the conference that it has used a range of recycled products in transportation applications, including fly ash as structural fill, scrap tires as lightweight embankment fill, and crumb rubber to modify the asphalt binder for HMA.
Conference discussions produced a number of action items to be worked on. The states and GHP are to work to harmonize Mid-Atlantic Regional State specifications for using recycled materials. More demonstration of real-world applications of recycled materials in highway construction should be carried out. GHP Recycle/Reuse Team is working with VDOT to incorporate recycled materials into multiple projects in 2009. "We are considering three possible project sites right now," says Stan Hite, Assistant Materials Engineer for VDOT. "Recycled materials being considered for use include shredded tires, steel slag, asphalt shingles and foundry sand." Other materials that will be considered are coal ash and paper mill sludge compost. Once projects have been selected, the GHP plans to showcase them in a 2009 workshop for the Mid-Atlantic States.
One of the key recycling partners is the Recycled Materials Resource Center (RMRC), which is staffed by national experts in the area of industrial by-product materials used in recycling. The center is staffed by engineers from both the University of New Hampshire and the University of Wisconsin at Madison, and is an important source of information for agencies and contractors considering greater use of recycled materials. The RMRC systematically tests, evaluates and develops guidelines for the use of recycled materials in transportation infrastructure construction and maintenance. Visit the RMRC website (http://www.rmrc.unh.edu/) where published research findings and technical information on the use of various by-products are posted.
Recycling successes continue to increase
Each year, approximately 80 percent of 200 million tons of old asphalt roadways are milled and hauled offsite for processing to later be recycled into new Hot Mix Asphalt (HMA) or used in some other application for highway construction. The transportation industry leads others in this respect. For instance, the amount of municipal solid waste recycled yearly (cans, bottles and newspapers) is 82 million tons—only about half of the amount of asphalt roadway material being recycled.
In addition, nearly 50 million tons of asphalt paving is being recycled-in-place, to be reused in the project. This in-place recycling process allows for 100 percent of roadway material to be reused while conserving resources of asphalt binder and aggregates, and reducing greenhouse gas emissions and fuel resources.
FHWA has done several state-of-practice reviews on the use and benefits of recycling. Two of the recycling technologies that were reviewed, Recycled Concrete Aggregate (RCA) and Cold In-place Recycling, are particularly underutilized. Use of Reclaimed Asphalt Pavement (RAP) was studied to help encourage use of this material at a higher rate in HMA. The findings from the different reviews were encouraging in that more states and agencies are using the technology and some good practices were gathered up for the report. For instance, when looking at the rate of reuse of RAP in HMA, it was noted that the process is helping to reduce energy consumption by 29 trillion BTUs yearly. The amount of RAP used yearly in HMA production has avoided almost two million tons of carbon dioxide emissions.
Coal fly ash, a product of the burning of coal in power plants, is another material commonly recycled in roadways. Not only does fly ash replace structural fill in road construction, it also replaces a portion of the Portland cement that is used to make concrete. Currently 15 million tons of fly ash is used in place of cement, which reduces carbon dioxide emissions by 10.5 million tons.
FHWA and the Asphalt Recycling and Reclaiming Association recently hosted the first regional in-place recycling workshop in Salt Lake City. More workshops are planned for the future. For more information on upcoming workshops, contact FHWA's pavement recycling expert, Jason Harrington, at (202) 366-1576 or Jason.Harrington@dot.gov.
Goals for the future of recycling
In light of the rapidly rising cost of materials, as well as the diminishing supply of quality aggregates, recycling technologies are almost required in order to effectively and economically build, rehabilitate and preserve our nation's highways. This issue alone is a major reason to take a closer look at recycling technologies and how they can be used in your program.
We can't stop here. We need to continue to provide the best resources, keep demonstrating beneficial uses and, through research, improve materials and technologies. Strong partnerships have been a big part of past success, and FHWA will do more to reach out to local agencies to share information, and encourage use of the various recycling technologies.
The FHWA looks forward to working with APWA and their members for help in sharing recycling technologies so that highway industry can make an even bigger impact—on saving money, improving roads and helping to enhance the overall environment. For more information, contact FHWA's Jason Harrington at (202-366-1576) or Jason.Harrington@dot.gov.
Three E's of Recycling
Engineering feasibility. A project will need to perform as designed and provide acceptable service over the life of the design. FHWA does not want to incorporate a material or process that will adversely impact the service life of a highway.
Environmental soundness. The project's elements should not impact the local human and natural environment. The U.S. EPA and the various state environmental regulators are excellent sources of technical information on using industrial by-products for highway construction materials.
Economic efficiency. The materials being used should not be cost-prohibitive. But initial cost should not be the sole consideration because enhanced performance or reduced maintenance needs over time can result in overall cost savings. Other cost savings associated with using recycled materials are lower disposal fees and landfill conservation of space. Other potential benefits are reduced greenhouse gas production, reduced energy costs and fewer impacts from not having to mine virgin materials.
Government-wide Recognition for Recycling Success
The FHWA was recently notified it had won the "Closing the Circle" award from the White House Office of the Federal Environmental Executive. This prestigious award recognizes outstanding achievements by federal employees and agencies for efforts that resulted in significant contributions to positive impacts regarding environmental stewardship. FHWA received the award in recognition of the efforts of staff members at many levels to help promote recycling technology across the nation, working with partners across the highway industry.
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