The Continuing Search for a HMA Cracking Test: Single Shot Versus Repeated-Load Testing

Hot mixed asphalt (HMA) overlay is one of the most commonly used methods for rehabilitating deteriorated pavements. One major type of distress influencing the life of an overlay is reflective cracking. Currently, the Texas Department of Transportation (TxDOT) uses the Overlay Tester to evaluate the cracking susceptibility of HMA mixes under repeated loading mode in the laboratory. In an effort to better understand the crack propagation properties of HMA pavement overlays, laboratory tests are performed to evaluate the fracture properties of HMA mixes. This study evaluated the prospects of using the Overlay Tester (OT) to perform a rapid monotonic loading “single shot” test as a practical method for characterizing the fracture properties of HMA mixes. HMA mixes that are typically used on Texas highways were tested at various temperatures and loading rates to evaluate the proposed monotonic OT test configuration. Analytical models were developed and used to compute the HMA fracture parameters, namely tensile strength, tensile strain at peak failure load, tensile modulus, and the fracture energy. Both the magnitude and variability of these fracture parameters were found to be comparable with the variability associated with the other monotonic fracture tests for HMA mixes. However, while variability was found to be lower, the OT monotonic test (tensile strength, strain at peak load, tensile modulus, and fracture energy) was not as effective as the standard repeated loading OT test (i.e., using the number of cycles) in terms of screening and discriminating mixes or being sensitive to changes in the asphalt-binder content or temperature variations.It is concluded that the repeated load test which incorporates a crack propagation phase is a much better discriminator of HMA cracking potential than any monotonic loading “single shot” test.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AFK50 Characteristics of Asphalt Paving Mixtures to Meet Structural Requirements. The DVD Table of Contents lists the title of this paper as "Continuing Search for a Hot-Mix Asphalt Cracking Test: Single Shot Versus Repeated-Load Testing".
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Walubita, Lubinda F
  • Faruk, Abu Nayeem
  • Das, Gautam
  • Izzo, Richard
  • Haggerty, Brett
  • Scullion, Tom
• Conference:
  • Transportation Research Board 91st Annual Meeting
  • Location: Washington DC, United States
  • Date: 2012-1-22 to 2012-1-26
• Date: 2012

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 17p
• Monograph Title: TRB 91st Annual Meeting Compendium of Papers DVD

Subject/Index Terms

• TRT Terms: Cracking; Failure; Hot mix asphalt; Laboratory tests; Overlays (Pavements); Repeated loads; Tensile strength
• Subject Areas: Highways; Maintenance and Preservation; Materials; Pavements; I30: Materials; I60: Maintenance;

Filing Info

• Accession Number: 01372861
• Record Type: Publication
• Report/Paper Numbers: 12-2595
• Files: TRIS, TRB
• Created Date: Jun 15 2012 4:04PM