The National Asphalt Pavement Association has provided testimony to a U.S. House of Representatives subcommittee "to set the record straight about the environmental sustainability of asphalt pavements," it says.
NAPA’s testimony sets out asphalt’s record on recycling, low carbon footprint, safety enhancements and fuel consumption reductions. In addition, the testimony counters a number of statements about asphalt which were provided to the subcommittee by the American Concrete Pavement Association (ACPA).
NAPA President Mike Acott commented, "There is no question that asphalt is the more environmentally sustainable pavement of the two. NAPA’s policy in the past has been to strive for continuous improvement in all aspects of our product that affect the environment and to publicize the benefits of asphalt, but not to denigrate the competing pavement type in front of Congress. However, the concrete industry made a number of statements about asphalt and put them into the hearing record. We had no choice but to respond with factual information."
Acott said, "NAPA interprets the intent of ACPA’S testimony as an effort to alter time-tested pavement type selection processes which are working well. It also seeks to create federal guidelines based on ACPA’s vision of what makes a pavement sustainable and diminish the independence of state DOTs in pavement type selection."
The hearing was before the Subcommittee on Technology and Innovation, which is part of the Committee on Science and Technology. Neither the subcommittee nor the committee has oversight over highway funding, although they will have jurisdiction over sections of the highway bill governing research.
"NAPA determined that to stay silent in the face of ACPA’s attack might ultimately have proved detrimental to the asphalt industry," continued Acott. "In addition, NAPA opposes any attempt to federalize decisions about what pavement type to choose.
"NAPA’s position is that local conditions require the existing oversight of the state and local governments to remain in place. The asphalt pavement industry is proud to be a partner of the state DOTs, the American Association of State Highway and Transportation Officials (AASHTO), and the Federal Highway Administration (FHWA) in these agencies’ quest for continuing improvement in providing pavements that meet the nation’s needs."
The stated purpose of the hearing was to discuss ways to improve energy efficiency and sustainability in the transportation sector; to discuss research that would further those aims and to identify the appropriate roles of government agencies and academia.
Acott’s testimony emphasized the impressive track record of the asphalt industry in supporting and implementing research that improves pavement performance and durability – important factors in long pavement life and, therefore, in sustainability. These achievements include Superpave and stone-matrix asphalt. He cited the National Asphalt Roadmap for Research and Technology, which embodies the asphalt industry’s research agenda. The document was developed by a partnership that included FHWA, AASHTO, Asphalt Institute, National Stone, Sand, and Gravel Association, and NAPA. Acott also referenced the asphalt industry’s support of Arizona State University's National Center of Excellence on SMART Innovations for Urban Climate and Energy.
Additional achievements of the asphalt industry cited by Acott included:
- Recycling. The asphalt industry is America’s number one recycler. Recycling not only saves precious natural resources, it also reduces the carbon footprint and energy footprint of pavement construction. Of the 100 million tons of asphalt pavement reclaimed each year, about 75 million tons is mixed with virgin materials and incorporated into new asphalt pavement. This is called the highest and best use because the asphalt cement in the old pavement is reactivated, becoming part of the binder for the new pavement and replacing some of the virgin binder that would otherwise be required. Another 20 million tons of reclaimed asphalt pavement, or "RAP," is reused in other ways in highway building. Aside from recycling its own product, the asphalt industry incorporates materials from other industries, including used tires, waste roofing shingles, glass, and many others, into high-quality pavements.
- Smooth Roads. We know that smooth roads conserve energy and extend the life of pavements. Studies at a pavement test track in Nevada have shown that driving on smoother surfaces can reduce fuel consumption in the neighborhood of 4.5 to 5 percent compared to fuel consumption on a rough pavement. Experts also estimate that a 25 percent increase in smoothness can result in a 10 percent increase in the life of pavements. In other words, smooth roads conserve fuel, save money and last longer. While both pavement types can be constructed for smoothness, it is easier and more economical to build smooth asphalt pavements. Many states recognize this fact in their pavement specifications, requiring better smoothness scores for new asphalt pavements than for new concrete ones.
- Safety. Open-graded asphalt surfacings are widely used on highways to enhance safety. Ensuring the safety of our highways is always a top priority with agencies and contractors alike. Using porous friction courses on pavement surfaces helps to eliminate tire splash and spray in rainstorms. Not only does this enhance tire-to-pavement contact, and therefore safety, it also improves drivers’ visibility. In a high-accident area in Texas, replacement of a typical non-porous surface with porous friction course reduced wet-weather accidents by 93 percent and reduced fatalities by 86 percent. To date, a successful concrete open-graded surfacing material for high-speed pavements has not been developed because concrete’s brittleness causes it to crack and ravel under traffic.
- Porous asphalt pavements. Open-graded and porous pavements hold great promise for water quality improvement. Porous asphalt pavements of both types – open-graded surfaces for highways, and porous pavement systems for stormwater management – have been used widely for over 20 years with an excellent record of success.
NAPA’s response to ACPA’s assertions about asphalt came from Dave Newcomb, PE, PhD, NAPA Vice President—Research and Technology. Among the points raised:
- While ACPA alleged that concrete lasts longer than asphalt, NAPA cited studies from a number of states showing that asphalt is long-lasting and economical.
- ACPA asserted that concrete is 100 percent recyclable and reusable, but Portland cement cannot be rehydrated, and therefore reclaimed concrete yields low-value material which can be used only as aggregate in limited applications. This is in contrast to reclaimed asphalt, in which the asphalt cement is reactivated for the highest and best use.
- ACPA said that concrete pavements have a lower energy footprint than asphalt, but failed to include the manufacture of Portland cement in their calculations.
- ACPA claimed that constructing only concrete pavements throughout the United States would reduce carbon dioxide emissions significantly. NAPA countered with information from the National Information of Standards and Technology showing that CO2 emissions associated with asphalt are only about 30 percent of concrete’s.
- ACPA alleged that concrete pavements mitigate the urban heat island effect. NAPA pointed out that the United States Environmental Protection Agency says, "there is no official standard or labeling program to designate cool paving materials, and research in this area is in an early stage." Urban heat island mitigation is not a black and white issue. For example, concrete pavements surfaced with open-graded asphalt have been shown to be cooler than plain concrete pavements.
Acott and Newcomb’s testimony has been posted to NAPA’s Web site at www.hotmix.org/PDFs/2008/NAPAHearingStatement_FINAL.pdf.