Quantifying the Role of Coarse Aggregate Strength on Resistance to Load in HMA

Several methods are available to determine aggregate characteristics, but their relationship to field performance, aggregate structure in hot mix asphalt (HMA), and traffic loading needs to be further investigated and defined. Current laboratory protocols do not correlate well with aggregate abrasion, toughness, and strength requirements during handling, construction, and service. Specifications should ensure that aggregate particles possess the necessary strengths to avoid degradation during handling, construction, and trafficking. This report discusses the determination of protocols and recommendations on the characteristics of the aggregates in a multifaceted way, considering the geological, geotechnical and mix design, to ensure accurate, economical, and time efficient testing methods. The use of these parameters in a micro-mechanical model to predict the performance is also discussed. Correlations and analytical investigations were performed on the results of existing Texas Department of Transportation (TxDOT) tests methods, as well as those not currently specified by TxDOT. The recommended tests were found to be promising with advantageous relationships with existing tests as alternatives. The Schmidt Hammer, Seismic Modulus (V-meter), and Indirect Tensile Strength tests were beneficial to be performed on bulk rock samples and cored rock specimens for their simplicity and time consumption. British Standards tests, i.e., Aggregate Crushing Value (ACV), prove to be very reliable methods in finding aggregate properties; for example, rock strength and modulus. Traditional tests are mentioned in this report as effective tests to characterize aggregate angularity and texture. The same investigation was done in HMA performance tests to discover methods that may prove to be useful and accurate. Dynamic Modulus and Flow Time are time consuming. Three other performance methods are tested to consider alternatives. The Indirect Tensile Strength, Seismic Modulus (V-meter), and the Hamburg Wheel Tracking Device tests demonstrate very good results to portray HMA performance and the role of aggregates in the new generation HMA mixes.

  • Record URL:
  • Supplemental Notes:
    • Research Study Title: The Role of Coarse Aggregate Point and Mass Strength on Resistance to Load in HMA.
  • Corporate Authors:

    University of Texas, El Paso

    Center for Transportation Infrastructure Systems
    500 W University Avenue
    El Paso, TX  United States  79968-0516

    Texas Department of Transportation

    Research and Technology Implementation Office, P.O. Box 5080
    Austin, TX  United States  78763-5080

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Reyes, Jaime
    • Mahmoud, Enad
    • Abdallah, Imad N
    • Masad, Eyad A
    • Nazarian, Soheil
    • Langford, Richard
    • Tandon, Vivek
  • Publication Date: 2008-6


  • English

Media Info

  • Media Type: Web
  • Edition: Technical Report
  • Features: Appendices; Photos; References; Tables;
  • Pagination: 172p

Subject/Index Terms

Filing Info

  • Accession Number: 01141681
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-08/0-5268-2, Report 0-5268-2
  • Contract Numbers: Project 0-5268
  • Created Date: Oct 9 2009 3:05PM