Models for Predicting Top-Down Cracking of Hot-Mix Asphalt Layers

Until recently, load-associated fatigue cracking of hot-mix asphalt (HMA) concrete-surfaced pavements that occurs in the wheel path has been thought to always initiate at the bottom of the HMA layer and propagate to the surface. However, recent studies have determined that load-related HMA fatigue cracks can also be initiated at the surface of the pavement and propagate downward through the HMA layer. The penetration of water and other foreign debris into these cracks can further accelerate the propagation of the crack through the HMA surface layer. These studies indicate that environmental conditions, tire-pavement interaction, mixture characteristics, pavement structure, and construction practices are among the factors that influence the occurrence of this cracking. Hypotheses regarding top-down cracking mechanisms have been suggested; test methods for evaluating HMA-mixture susceptibility to cracking have been proposed; and preliminary models for predicting crack initiation and propagation have been developed. Recent work completed under NCHRP Project 1-42 provided further review of some of the issues related to top-down cracking (see Special Note A). However, additional research is needed to address these and other issues associated with top-down cracking and to develop mechanistic-based models for use in mechanistic-empirical procedures for design and analysis of new and rehabilitated flexible pavements. The objective of the research is to identify or develop mechanistic-based models for predicting top-down cracking in HMA layers for use in mechanistic-empirical procedures for design and analysis of new and rehabilitated flexible pavements.


  • English


  • Status: Completed
  • Contract Numbers:

    Project 1-42A

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590

    American Association of State Highway & Transportation Officials

    444 North Capitol Street, NW, Suite 225
    Washington, DC    20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  USA  20001
  • Project Managers:

    Hanna, Amir

  • Performing Organizations:

    University of Florida, Gainesville

    219 Grinter Hall
    Gainesville, FL  USA  32611
  • Principal Investigators:

    Roque, Reynaldo

  • Start Date: 20060501
  • Actual Completion Date: 20091231
  • Source Data: RiP Project 11843

Subject/Index Terms

Filing Info

  • Accession Number: 01462921
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 1-42A
  • Files: RiP, USDOT
  • Created Date: Jan 3 2013 2:13PM