Base courses beneath highway and airport pavements that becomes saturated are reduced in modulus and bearing capacity, and pumping may develop at pavement joints. Base-course drainage is often required to preclude this major cause of pavement deterioration. A number of theoretical models for developing design guidelines for drainage requirements of pavements are discussed; the models include the original one by Casagrande and Shannon, which assumed a straight-line phreatic surface and an impermeable subgrade. The influence of subgrade drainage on drainage time and the influence of the use of the more theoretically correct parabolic phreatic surface, especially in deep base courses or on flat slopes, are found to be substantial. New models are developed to include these features and the calculated results are, in general, in good agreement wit field data observed on full-scale pavements. Example calculations are presented to illustrate the effect of subgrade drainage on the drainage time for base courses. (Author)

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 1-10
  • Monograph Title: Subgrade moisture: soil properties, foundations, tunnel reinforcement
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00389565
  • Record Type: Publication
  • ISBN: 0309036666
  • Files: TRIS, TRB
  • Created Date: Oct 30 1984 12:00AM