A procedure is presented for flexible pavement design in the tropics along with deflection criteria for flexible pavements. The deflection data were obtained during a research program that included pavement evaluation of over 200 sections in Africa and South America. Maximum permissible deflections were established for various ranges of traffic and are given in terms of average deflections plus two standard deviations. For the selection of a design deflection, emphasis is placed on the degree of uniformity in construction that is generally obtained by local construction practices. The flexible pavements design procedure is based on two relations: The first is between deflection and performance, and the second is between deflection and pavement strength. The structural evaluations were conducted on 170 test sections where deflections had been measured. Index properties and California bearing ratio density-moisture relations were determined for each soil layer within the excavated depth of 90 cm (36 in.). The thickness and density of each structural course was measured. Structural coefficients were developed for various depths beneath the pavement surface rather than by layer description because of the multiple-layer systems encountered. A minimum thickness of cover for various California bearing ratio values was established to provide adequate support. A minimum thickness was also established to prevent excessive pavement cracking. Structural design curves were developed that provide a relation between design traffic and pavement structural index for 3 degress of pavement uniformity. Design curves were also developed that provide a measure of the subgrade support and show minimum thickness of surface, base, and subbase that is required. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 28-36
  • Monograph Title: Design and performance of pavement overlays
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00173943
  • Record Type: Publication
  • ISBN: 030902658X
  • Files: TRIS, TRB
  • Created Date: May 18 1978 12:00AM