Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2021

A shared goal of the Federal Highway Administration (FHWA) and the National Asphalt Pavement Association (NAPA) is to support and promote sustainable practices, such as the use of recycled materials and warm-mix asphalt (WMA). The use of recycled materials, primarily reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS), in asphalt pavements conserves raw materials and reduces overall asphalt mixture costs, as well as reduces the stream of material going into landfills. WMA technologies have been introduced to reduce production and compaction temperatures for asphalt mixtures, which reduces the energy needed and emissions associated with mixture production. Additional benefits include improved low-temperature compaction of asphalt mixtures leading to improved pavement performance, as well as a longer paving season. WMA was chosen for accelerated deployment in Federal-Aid Highway, State Department of Transportation, and local road projects as part of FHWA’s 2010 Every Day Counts initiative. The objective of this survey, first conducted for the 2009 and 2010 construction seasons, is to quantify recycled materials used and WMA produced annually by the asphalt pavement industry to document the deployment of these technologies to understand where they are being used and where they are underutilized. Results show significant growth in the use of RAP, RAS, and WMA technologies since 2009, although the rate of year-overyear growth has generally slowed since 2013. The asphalt industry remains the country’s most diligent recycler with more than 99 percent of reclaimed asphalt pavement being put back to use. The average percentage of RAP used in asphalt mixtures has increased from 15.6 percent in 2009 to 21.9 percent in 2021. In 2021, the estimated RAP tonnage used in asphalt mixtures was 94.6 million tons. This represents 4.7 million tons (26 million barrels) of asphalt binder conserved, along with the replacement of more than 89 million tons of virgin aggregate. The use of RAS in asphalt pavement mixtures has decreased from 701,000 tons in 2009 to an estimated 630,000 tons in 2021 with the use of RAS increasing (7 percent) from 2020 to 2021. The combined savings of asphalt binder and aggregate from using RAP and RAS in asphalt mixtures is estimated at more than $3.5 billion and nearly 62 million cubic yards of landfill space. More than 1.3 million tons of other recycled materials were reported as being incorporated into nearly 9.2 million tons of asphalt pavement mixtures during the 2021 construction season, including recycled tire rubber, blast furnace slag, steel slag, and cellulose fibers. The estimated total production of asphalt with WMA technologies during the 2021 construction season was 177.9 million tons of which about 53 percent was produced at reduced temperatures. This was a 5 percent decrease from the estimated 186.4 million tons of WMA in 2020. Utilization of WMA technologies in 2021 was 959 percent more than the estimated 16.8 million tons in the 2009 construction season. Asphalt produced with WMA technology made up 41.1 percent of the total estimated asphalt mixture market in 2021. Chemical additive technologies, representing 60 percent of the market, is the most commonly used warm-mix technology; production plant foaming accounted for nearly 38 percent of the market. Differences were seen in which WMA technologies were used when production temperatures were or were not reduced.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: 12th Edition Final Report
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 153p

Subject/Index Terms

Filing Info

  • Accession Number: 01874563
  • Record Type: Publication
  • Report/Paper Numbers: IS 138(12e)
  • Contract Numbers: HIF180121PR
  • Files: TRIS, ATRI, USDOT
  • Created Date: Feb 24 2023 2:13PM