Documenting the Impact of Aggregate Quality on Hot Mix Asphalt (HMA) Performance

In Texas, the Surface Aggregate Classification (SAC) system is currently used to qualify aggregates for hot mix asphalt (HMA), which ranks aggregates into SAC A, B, or C based on their magnesium soundness and acid insolubility values. Only SAC A aggregate is recommended on high volume roads. However, this classification has led to shortages of surfacing aggregates and increment in the cost of premium HMA surfacings because limestone, a main Texas aggregate source, has a SAC B designation due to the acid insolubility requirement. It is Texas Department of Transportation's (TxDOT’s) long-term goal to revise and possibly replace the existing SAC system with a system more related to in-service field performance. The main objective of this study is to provide the fundamental laboratory and field performance data required to make major changes of the current SAC system and provide guidelines for the enhancement of the Texas aggregate screening/selection criteria. To accomplish these objectives, the researcher team will use the existing databases (mainly the Project 0-6658 database with over 70 in-service highway test sections across the State and other in-house district databases) to correlate field performance in terms of skid resistance, as well as rutting and cracking, with the aggregate properties – supplemented with limited field data (skid) collection.


  • English


  • Status: Completed
  • Funding: $250000
  • Contract Numbers:


  • Sponsor Organizations:

    Texas Department of Transportation

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

    Kuhr, James

  • Performing Organizations:

    Texas Transportation Institute

    Texas A&M University System
    3135 TAMU
    College Station, TX  United States  77843-3135

    The University of Texas at Tyler

    3900 University Blvd
    Tyler, TX  United States  75799
  • Principal Investigators:

    Walubita, Lubinda

  • Start Date: 20170901
  • Expected Completion Date: 20201031
  • Actual Completion Date: 20191031

Subject/Index Terms

Filing Info

  • Accession Number: 01648624
  • Record Type: Research project
  • Source Agency: Texas Department of Transportation
  • Contract Numbers: 0-6959
  • Files: RIP, STATEDOT
  • Created Date: Oct 20 2017 11:45AM