Allowable Maximum Recycled Binder Ratio (RBR) Specification

The Performing Agency shall explore the use of different recycled binder ratios (RBR) with mixtures containing recycled asphalt pavement (RAP) that range from TxDOT-friendly mixes—high cost, low risk (PG76, no RAP)—to contractor-friendly mixes—low cost, relatively higher risk (PG 64 + 50% RAP)— with sufficient control points in between to refine and validate the existing specification with and without warm-mix asphalt (WMA) and recycling agents. The work plan is to address four technical objectives: A. Evaluate the performance of existing sections constructed with different combinations of recycled materials, recycling agent dosages, WMA additives or processes, and binder substitution towards identifying problematic recipes and ultimately recommending changes to the current specification. B. Perform laboratory evaluation of binder blends with various RBRs (combinations of virgin binder, recycled binder, recycling agents, and warm- mix additives), and corresponding mixes. C. Conduct field evaluation of binder blends at average and high RBRs and corresponding mixes. D. Investigate methods to enhance blending of binder, recycled materials, and additives at the asphalt plant during mix production. The Performing Agency shall deliver two different options for implementing revisions to the existing RBR specification: Option 1: A partially validated and expanded ‘Table 5’ that allows improvisation as needed and incorporates different RBRs, including the influence of recycling agents and WMA. Option 2: A new and simplified form of ‘Table 5’ coupled with a simple test and specification requirement to screen out potentially problematic mixes.


  • English


  • Status: Active
  • Contract Numbers:


  • Sponsor Organizations:

    Texas Department of Transportation

    125 E. 11th Street
    Austin, TX  United States  78701-2483
  • Project Managers:

    Jensen, Darrin

  • Performing Organizations:

    Center for Transportation Research

    University of Texas at Austin
    1616 Guadalupe, Suite 4.202
    Austin, Texas  United States  78701
  • Principal Investigators:

    Bhasin, Amit

  • Start Date: 20170609
  • Expected Completion Date: 20190831
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01648556
  • Record Type: Research project
  • Source Agency: Texas Department of Transportation
  • Contract Numbers: 0-6947
  • Files: RiP, STATEDOT
  • Created Date: Oct 18 2017 4:01PM