Overlay Tester: A Simple and Rapid Screening Test for Characterizing Crack Resistance of HMA Mixes

Stiffer binders and good stone-to-stone contact may provide improved rut resistance, but they may also reduce the mix flexibility and thus, crack resistance. This paper investigates the feasibility of using the Overlay Tester (OT) as a simple test for characterizing crack resistance of asphalt mixes. The OT can be run on standard size samples, typically 150 mm long by 75 mm wide by 38 mm high, which can be prepared from either field cores or from lab molded specimens. Sensitivity studies indicated that the OT provides reasonable results, in that raising the asphalt performance grade and decreasing the testing temperature will lead to shorter cracking life. Furthermore, in a series of controlled tests it was found that asphalt absorption by aggregate appears to have a major impact on crack resistance of asphalt mixes. The effectiveness of the OT as a crack resistance test was validated by five reflective cracking case studies in Texas and tests conducted on cores from MnROAD low-temperature cracking sections. The OT results correlated well with field performance. A laboratory study was also conducted to compare the OT results with those from the bending beam fatigue tests. A good correlation was also obtained. The OT device appears to be a practical tool to characterize cracking resistance of asphalt mixes and to let the mix designer balance the competing requirements of both rut and crack resistance.

• Corporate Authors:

  International Society for Asphalt Pavements

  4711 Clark Avenue, Suite G
  White Bear Lake, MN  United States  55110
• Authors:
  • Zhou, F
  • Scullion, T
• Conference:
  • 10TH INTERNATIONAL CONFERENCE ON ASPHALT PAVEMENTS - AUGUST 12 TO 17, 2006, QUEBEC CITY, CANADA
• Publication Date: 2006

Language

• English

Media Info

• Media Type: Print
• Pagination: p. vol1,215-24
• Monograph Title: 10th International Conference on Asphalt Pavements - August 12 to 17, 2006, Quebec City, Canada

Subject/Index Terms

• TRT Terms: Bituminous mixtures; Conferences; Cracking; Hot coated materials; Overlays (Pavements); Rutting; Test procedures
• Geographic Terms: Canada
• Subject Areas: Construction; Highways; I52: Construction of Pavements and Surfacings;

Filing Info

• Accession Number: 01084449
• Record Type: Publication
• Source Agency: Transportation Association of Canada (TAC)
• Files: TAC
• Created Date: Jan 16 2008 9:05AM