The results of a survey by the Rubberized Asphalt Foundation (RAF), a research foundation dedicated to the science and practical use of recycled tire rubber in asphalt pavements, reveals that 70 percent of transportation agencies have previously used or currently use recycled tire rubber in asphalt. About half of the respondents indicate that they have a specification for using recycled tire rubber. The survey was conducted for RAF by the Highway Sustainability Research Center at the University of Massachusetts Dartmouth and was distributed to 152 transportation professionals, including members of each state transportation agency, the Federal Highway Administration (FHWA), and other government agencies.
“The results of our survey reveal the decisions currently being made by transportation officials regarding the use of recycled tire rubber in asphalt pavements,” said George Way, chairman of RAF. “In the future, we will conduct an analysis to account for the amount of recycled tire rubber being used by each agency.”
Agencies have utilized recycled tire rubber routinely for crack sealing (30 percent), chip seals (26 percent), dense-graded hot mix asphalts (15 percent), joint sealants (15 percent), stress absorbing membrane interlayers (11 percent), and open-graded friction courses (11 percent). Other respondents reported the same uses for rubberized asphalt on an experimental basis. Another aspect of the survey notes the technologies being used by transportation agencies to incorporate recycled tire rubber into their pavements. These results show that terminal blending is the predominate method currently being used. It is being chosen 59 percent of the time.
A full report of the findings is available at www.ra-foundation.org.