A MODEL UTILIZING CLIMATIC FACTORS FOR DETERMINING STRESSES AND DEFLECTIONS IN FLEXIBLE PAVEMENT SYSTEMS

In this paper, a model for determining the stresses and deflections at various locations in a multilayered flexible pavement system as a function of load, climatic exposure conditions, and material characteristics is described. Application of the model to a flexible pavement section at the AASHO Road Test and comparison of theoretical stresses and deflections with measured stresses and deflections at various times during the life of the section is made. The comparisons relate the applicability of the model for pavement analysis. The model combines a heat-transfer model for evaluating frost conditions and temperature-related effects, with an elastic layer model for stress and deflection determination. The heat-transfer portion of the model was derived from one-dimensional, forward-finite-difference, heat-transfer theory. This portion of the model was used to generate temperature profiles and frost-line locations in the pavement system at a specified time. It was designed to include many input parameters such as short-wave radiation, long-wave radiation, convection, and air temperature. Other factors considered are physical properties and thermal properties of the pavement materials including unit weight, moisture content, material classification, thermal conductivity, heat capacity, and latent heat. The model was developed so that appropriate thermal properties of the pavement materials are used depending on whether or not an unfrozen or frozen state exists. In addition, it can be easily expanded to include newly developed parameters. The model has been programmed for computer solution. The stresses and deflections at various locations in a multilayered flexible pavement system were determined based on Burmister's elastic layer layer theory. A computer routine, developed by Chevron Research Corporation and modified to work on the University of Illinois' computer system, was employed for solution. Modular values and layer thicknesses were established based on layer interface location, frost-line location, and layer condition (frozen or unfrozen). Stiffnesses of the asphaltic concrete surface and binder layers were determined by use of the procedure developed by Van der Poel and revised by Heukelom and Klomp. A correction for air content when in excess of three per cent, as suggested by Van Draat and Sommer, was also employed. Average layer stiffnesses for the surface and binder layers were determined and utilized for computation of stresses and deflections in the system at a specified time. Using the model, theoretical stresses and deflections for Section 581 from the AASHO Road Test were computed for the period of July 1, 1959 to June 30, 1960. Comparisons were then made between theoretical and measured stress and deflection values to substantlate the applicability of the model for theoretical analysis of pavement systems. /AUTHOR/

  • Supplemental Notes:
    • Presented at the Third International Conference on the Structural Design of Asphalt Pavements, Grosvenor House, Park Lane, London, England, Sept. 11-15, 1972.
  • Corporate Authors:

    International Conf Struct Design Asph Pvmts (3rd)

    University of Michigan, Department of Civil Engineering
    Ann Arbor, MI  USA  48104

    International Conf Struct Design Asph Pvmts (3rd)

    University of Michigan, Department of Divil Engineering
    Ann Arbor, MI  USA  48104

    Interrational Conf Struct Design Asph Pvmts (3rd)

    University of Michigan, Department of Civil Engineering
    Ann Arbor, MI  USA  48104
  • Authors:
    • Marek, C R
    • Dempsey, B J
  • Conference:
  • Publication Date: 1972-9

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 101-114
  • Serial:
    • Volume: 1

Subject/Index Terms

Filing Info

  • Accession Number: 00261969
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Oct 22 1974 12:00AM