The upside-down design, consisting of a thin bituminous surfacing and an untreated granular base overlying a cement-treated sub-base, is discussed in this paper. The inter-dependence between the thicknesses of the three materials and the response to overloaded wheels were analysed with a computer program capable of stress-modulus iteration, PSAD2A. From this study it was concluded that the flexible surfacing should be about 30 to 35 mm thick and that it is structurally more beneficial to increase the thickness of the treated sub-base than that of the granular base. For highway-type loading the granular layer should preferably be 125 to 150 mm while the cement-treated layer should be about 300 to 375 mm thick. During overloading it is the cement-treated sub-base that is strained excessively and very little damage is done to the untreated granular base-course. /Author/TRRL


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 1-7
  • Serial:
    • Volume: 8
    • Issue Number: 1

Subject/Index Terms

Filing Info

  • Accession Number: 00164199
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS, ATRI
  • Created Date: May 18 1978 12:00AM