DISTRIBUTIONS OF STRAIN COMPONENTS AND WORK WITHIN FLEXIBLE PAVEMENT STRUCTURES

An investigation was made to determine the location along the centerline of the axle of the maximum strain energy density, or work, in the pavement as defined by classical physics. The location is under the inside edge of either dual tire. The most influential strain was the shear component. The distribution of shear strains and stresses with depth through the full-depth asphaltic concrete and into the subgrade was investigated. Using Simpson's rule for an even number of increments, or using the trapezoidal rule, allows the summation of strain energy density to be calculated at various depths. The sum of work throughout the pavement structure provides a greater insight to the behavior of the pavement because all components of strain, or stress, are considered and the variation throughout the depth may be large according to the location within the tire print. The sum of strain energy density is much greater under the edge of the dual tire than under the center of the dual tire, yet the magnitude of the strain energy density at the bottom of the asphaltic concrete may be nearly identical. For an 18-kip, four-tired, single axle load, the depth of maximum shear is approximately 35 to 40% of the thickness from the surface downward for a maximum pavement thickness of approximately 8 in.; thereafter the depth of maximum shear moves toward the surface as thickness increases. An investigation of shear stress indicated that the maximum value was approximately 67 psi due to an 18-kip single axle load and tire contact pressure of 80 psi within a 4-in. full-depth asphaltic concrete pavement. Investigation of three pavements indicated shear flow could be seen as deep as 6 in. below the surface. From the stress analyses presented, the stress at the 6-in. depth would be approximately 25 psi. An established critical value for the shear stress of asphaltic concrete is not known.

Media Info

  • Features: Figures; References;
  • Pagination: p. 39-50
  • Monograph Title: Pavement analysis, design, rehabilitation, and environmental factors, 1991
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00621580
  • Record Type: Publication
  • ISBN: 0309051177
  • Files: TRIS, TRB
  • Created Date: Apr 30 1992 12:00AM