The Effect of Material Transfer Devices on HMA Material Uniformity and Ride Quality

Alabama Department of Transportation (ALDOT) recently started to require contractors to use a material transfer device (MTD) in the construction of hot mix asphalt (HMA) pavements in order to minimize segregation. While some research has been done that indicates that the use of a MTD will minimize both temperature and gradation segregation of the mix components once the mix leaves the HMA plant, no research has been done to evaluate the impact of a MTD on initial ride quality. The objectives of this research were to document the influence of MTDs on improving both mix uniformity (i.e., lack of segregation) and initial ride quality. The scope of this project included the evaluation of four Alabama HMA projects constructed during the 2001 and 2002 paving seasons. On three of the four projects, both the binder and surface courses were evaluated. Areas of non-uniformity were identified during construction using an infrared camera, with areas having temperature difference of more than 19 degrees F being classified as non-uniform. Both ride quality and uniformity after construction was completed were identified using data from the Auburn University Roadware inertial profiler. Results show that the inclusion of a MTD in the HMA paving train can significantly reduce the non-uniformity of the mix as measured by either temperature differences or texture variations. A MTD also results in significantly smoother HMA pavements. These conclusions are based on the paving operations moving continuously. Any stops, with or without a MTD, will result in both more non-uniform (potentially segregated) areas and a rougher ride.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Edition: Final Report
  • Features: CD-ROM; Figures; References; Tables;
  • Pagination: 64p

Subject/Index Terms

Filing Info

  • Accession Number: 01003129
  • Record Type: Publication
  • Report/Paper Numbers: ALDOT Research Project 930-471
  • Files: NTL, TRIS, STATEDOT
  • Created Date: Aug 10 2005 2:41PM