SHEAR SUSCEPTIBILITY OF ASPHALTS IN RELATION TO PAVEMENT PERFORMANCE

In order to study the shear susceptibility parameter in relation to the performance of in-service pavements, six test pavements (6 experimental sections of ID-2 wearing course surfaces) constructed of graded asphalt from different sources were evaluated in a closely controlled research project. Periodic core samples were used to determine air voids in the pavements and the rheological properties of the aged asphalts. Details of the rating method for evaluation of the effect of asphalt aging on pavement condition are detailed in a reference. Viscosities were determined at 39.2 G, 77 F and 115 F over a range of shear rates, using the sliding plate microviscometer and viscosity at 140 F was determined using the Cannon-Manning Vacuum Viscometer. The aging indices were determined (considering the changes in viscosity at 77 F and viscosity at 140 F), as follows: aging index = viscosity after aging/viscosity before aging. The shear susceptibility (shear index) value as employed in this-study is the tangent of the angle of log shear rate (x-axis) versus log viscosity (y-axis) determined during performance of the viscosity test. The effects of temperature and asphalt composition on shear susceptibility are discussed. Very good correlation was observed between aging indices and shear susceptibility values of the aged asphalts. Aging index-shear susceptibility of relationship appears to determine pavement performance. Control of grain in shear susceptibility and aging index seems to be a necessary specification requirement for paving asphalts. The studies indicate that the ratio of asphaltenes to Nitrogen Bases affects the shear susceptibility of asphalts.

  • Supplemental Notes:
    • Proceedings of the meeting held in Houston, Texas, February 1973.
  • Corporate Authors:

    University of Minnesota, Minneapolis

    155 Experimental Engineering Building
    Minneapolis, MN  USA  55455
  • Authors:
    • Kandhal, P S
    • Sandvig, L D
    • Wenger, M E
  • Conference:
  • Publication Date: 1973

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 99-125
  • Serial:
    • Volume: 42

Subject/Index Terms

Filing Info

  • Accession Number: 00127326
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 16 1975 12:00AM