Standardization of SIP Calculation for Hamburg Wheel Tracking Test

The Hamburg Wheel Tracking Test (HWTT) is one of the most popular laboratory tests used by state highway agencies (SHAs) to evaluate the rutting resistance of asphalt mixtures. Because the test is conducted in water, it also allows the evaluation of moisture susceptibility based on the stripping inflection point (SIP). According to AASHTO T 324, SIP is determined graphically as the intersection of slopes of the two fitted lines to the creep and stripping phases of the HWTT curve. Although the definition of SIP is straightforward, accurately determining SIP can be challenging because HWTT data do not always provide well-defined SIP, especially those with a marginal stripping failure. Over the years, HWTT equipment manufacturers and asphalt practitioners have developed different methods for calculating SIP, but they do not always yield the same results. The lack of standardization for SIP calculation could cause unnecessary disputes for SHAs when evaluating the HWTT results for mix design approval and production acceptance. This proposed project aims to develop HWTT analysis software to standardize and automate the calculation of SIP, which allows SHAs to make the most informed and undisputable decisions on the HWTT results. The software will be compatible with different HWTT devices to enable direct reading and processing of the raw data files without subjective data manipulation and interpretation.

  • Supplemental Notes:
    • TPF-5(466)


  • English


Subject/Index Terms

Filing Info

  • Accession Number: 01905383
  • Record Type: Research project
  • Source Agency: Minnesota Department of Transportation
  • Contract Numbers: 1036333-WO-08
  • Files: RIP, STATEDOT
  • Created Date: Jan 23 2024 2:07PM