Synthesis of Information Related to Highway Practices. Topic 52-17. Use of Rejuvenators in Asphalt Concrete Mixtures Containing High RAP

The Federal Highway Administration (FHWA) has highlighted the importance of using recycled materials in the highway construction industry, due to the engineering, economic, and environmental benefits. In the case of reclaimed asphalt pavement (RAP), its use continues increasing in highway construction, particularly to reduce the amount of virgin and non-renewable materials, as RAP contains old asphalt binders and aggregates. Milled asphalt concrete (AC) mixtures are significantly stiffer than fresh mixtures as they have experienced in-service oxidative hardening and other aging-related processes. Thus, although the use of high RAP (more than 25% of the total mixture) in new AC mixtures may increase the rutting resistance of pavements, it may also compromise cracking resistance performance. To avoid this problem, AC mixtures with high RAP contents usually require the use of a softer binder or a rejuvenator. Not all departments of transportation (DOTs) have experimented with high RAP content mixtures. The common factors preventing the use of more RAP include specification limitations, lack of expertise in processing RAP, lack of availability of quality RAP, and negative prior experiences. The objective of this synthesis is to document current practices in DOTs to rejuvenate AC mixtures with high RAP contents. Information to be gathered includes (but is not limited to): (1) Existing policies and guidelines related to the use of rejuvenators; (2) Current practices for the use of rejuvenators in AC mixtures with RAP; and (3) Rejuvenation techniques and evaluation methods (e.g., physical, mechanical, chemical, mathematical, and chemical models) and performance metrics. Information will be collected through literature review, a survey of DOTs, and follow-up interviews with selected agencies for the development of case examples. Information gaps and suggestions for research to address those gaps will be identified.


  • English


  • Status: Active
  • Funding: $45000
  • Contract Numbers:

    Project 20-05, Topic 52-17

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Gause, Jo

  • Start Date: 20200501
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01739674
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic 52-17
  • Files: TRB, RiP
  • Created Date: May 18 2020 3:05PM