The orientation of aggregate particles in field and laboratory compacted specimens

A study was undertaken to determine whether there were differences in aggregate particle orientation between field asphalt and laboratory compacted samples manufactured using Marshall and Gyropac equipment. Samples of one particular mix composition were obtained from the Accelerated Loading Facility (ALF) asphalt deformation trial in Queensland. Field mix and laboratory compacted samples were sectioned and the orientation angle of exposed aggregate particles determined by visual inspection of the cut faces. Orientation angle data were graphed as frequency histograms, using 10 degree class intervals, and as cumulative frequency polygons. Application of the Tukey Chi-Square method indicated that, in most cases, there was evidence of aggregate particles having a preferred orientation (as opposed to being randomly orientated). Two quantitative measures of orientation direction were developed: (a) the mean orientation angle, calculated by vector addition of the resolved vertical and horizontal components of the orientation angles, and (b) the proportion of particles oriented within 22.5 degrees of the horizontal. The results suggested that aggregate packing in the Marshall and Gyropac compacted samples was different to that in field compacted mix. Although the Gyropac results indicated a slightly closer orientation of particles to the horizontal than Marshall, this could not be confirmed. The available data was insufficient to determine the repeatability and reproducibility of the orientation parameters and a more extensive investigation would be required to verify the conclusions on a statistical basis.

Language

  • English

Media Info

  • Pagination: 9.1-17
  • Serial:
    • Issue Number: 12

Subject/Index Terms

Filing Info

  • Accession Number: 01437729
  • Record Type: Publication
  • Source Agency: ARRB
  • ISBN: 086910683X
  • Files: ATRI
  • Created Date: Aug 24 2012 9:00PM