Not only does asphalt provide the smoothest, quietest ride, it also is the most sustainable option for paving. Over the years, the asphalt pavement industry has been a constant innovator in finding ways to make its products more environmentally friendly — from reclaiming old asphalt pavements and rejuvenating their component parts for use in new pavements to the incorporation of recycled materials to the adoption of energy-saving warm-mix asphalt technologies.
As early as 1993, the Environmental Protection Agency and Federal Highway Administration identified asphalt pavement as America's No. 1 recycled product in a report to Congress. It continues to be reclaimed and reused at a greater rate than any other product in the U.S. A wide range of waste materials are now incorporated into asphalt pavements, including ground tire rubber, slags, foundry sand, glass, and even pig manure, but the most widely used are reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS). The use of recycled materials in asphalt pavements saves about 50 million cubic yards of landfill space each year.
NAPA, in partnership with the Federal Highway Administration (FHWA), is quantifying the use of these technologies through industry surveys. According to the latest survey data, during the 2015 construction season more than 74.2 million tons of RAP and nearly 2 million tons of RAS were put to use in new pavements in the United States, saving taxpayers more than $2.6 billion. Also, about a third of all asphalt pavement mixture produced in the country that year was made using warm-mix asphalt (WMA) technologies.
When reclaimed asphalt pavement and shingles are reprocessed into new pavement mixtures, the liquid asphalt binder in the recycled material is reactivated, reducing the need for virgin asphalt binder. Using reclaimed materials also reduces demands on aggregate resources. Warm-mix asphalt technologies allow asphalt pavements to be produced at lower temperatures, which means reduced energy demands, as well as lower emissions during production and paving.
Compared to previous FHWA/NAPA surveys covering the 2009–2014 construction seasons, the use of these sustainable practices has continued to increase.
In 2015, RAP usage in new asphalt pavement mixtures reached 74.2 million tons, a 32.5 percent increase from 2009. An additional 5.5 million tons of RAP were used as aggregate. At year-end 2015, some 85 million tons of RAP was estimated to be stockpiled for future use across the country. More than 99 percent of asphalt pavement reclaimed from roads and parking lots was reclaimed for use in new pavements instead of going into landfills. In the survey, 99 percent of producers reported using RAP in their mixes for new construction, pavement preservation, rehabilitation, and other projects.
RAS usage also continued to be strong, reaching to nearly 2 million tons in 2015 — a 175 percent increase since 2009. Since 2009, RAS usage has been reported in 41 states. RAS includes both manufacturers' scrap shingles and post-consumer roofing shingles, and about 15 percent of the total supply of waste shingles nationwide are recycled into asphalt pavements.
Producers were also asked about ground tire rubber, steel and blast furnace slags, and other waste materials repurposed into pavements. Although national estimates of usage were not calculated, survey respondents reported using more than 1.1 million tons of these materials in 2015 in the production of 8 million tons of asphalt paving mixtures.
In 2010, FHWA made warm-mix asphalt part of its Every Day Counts initiative to speed the deployment of technologies that can improve highway projects' quality, sustainability, and safety. In 2013, NAPA and FHWA were honored by the Construction Innovation Forum, earning a NOVA Award for their work promoting the uptake of WMA.
In 2015, total WMA tonnage in the U.S. was estimated at nearly 120 million tons, a greater than 5 percent increase from 2014 and a 614 percent increase since 2009. Most WMA in the U.S. was produced using a plant foaming process, which injects a small amount of water into the mix; warm-mix chemical additives accounted for about 25 percent of the WMA tons produced.
The full report and related materials, including a state-by-state breakdown of recycled materials usage, can be downloaded below:
- Press Release (2 pages)
- IS 138 Executive Summary (3 pages)
- IS 138 Full Report (40 pages)
- Appendix A (Survey Forms) (19 pages)
- Appendix B (State-by-State RAP, RAS, WMA Usage) (54 pages)
- The Impact of Asphalt Sustainability Infographic (High Resolution)
- Asphalt Pavement Mix Production Survey, 2009–2010
- Asphalt Pavement Industry Survey, 2nd Annual, 2011
- Asphalt Pavement Industry Survey, 3rd Annual, 2012
- Asphalt Pavement Industry Survey, 4th Annual, 2013
- Asphalt Pavement Industry Survey, 5th Annual, 2014
- Asphalt Pavement Industry Survey, 6th Annual, 2015