STRENGTHENING OF THIN ASPHALT PAVEMENTS. SIXTH INTERNATIONAL CONFERENCE, STRUCTURAL DESIGN OF ASPHALT PAVEMENTS, VOLUME I, PROCEEDINGS, UNIVERSITY OF MICHIGAN, JULY 13-17, 1987, ANN ARBOR, MICHIGAN

An overlay design method for strengthening thin asphalt pavements and gravel roads is developed. The method is based on deflection data and a two-layer elastic model, where the vertical compressive strain at the top of the subgrade is regarded as the critical response. The deflections are measured with the Falling Weight Deflectometer (150 mm radius of the loading plate) at the center of the loading plate (y sub 0) and at a distance of 450 mm from the center (y sub 450). The subgrade modulus is simply determined from the y sub 450 value, if the thickness of the granular base is less than 300 mm. The non-linear granular base modulus is replaced by an equivalent one-layer linear elastic modulus which is governed by the subgrade modulus and the type of base material. Measured deflections from a Swedish test road are shown to be in good agreement with those predicted by the two-layer model. The proposed failure criterion, developed from the AASHO Road Test data, can reasonably well explain the performance of two Swedish test roads with thin asphalt surfacings. The criterion leads to higher tolerable y sub 0 values with increasing y sub 450 values. The proposed overlay design method can be used for strengthening low-volume roads, if the existing pavement thickness is less than 300 to 400 mm. The deflections y sub 0 and y sub 450 and the thickness of the existing pavement are required data inputs.

  • Corporate Authors:

    University of Michigan, Ann Arbor

    Department of Civil Engineering
    Ann Arbor, MI  United States  48109
  • Authors:
    • Broms, H
  • Publication Date: 1987

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  • Accession Number: 00485651
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 31 1989 12:00AM