The paper first describes the method used to confirm the design of a pavement structure incorporating an old pavement and an overlay. A multilayer elastic model is used; an equivalent traffic and an equivalent temperature are used to take into account the variations of axle loads and pavement temperature. The method attempts to take into consideration the probabilistic nature of pavement distress, resulting from the scattering of pavement thickness, overlay material composition, fatigue life, and bearing capacity of old pavement. Distress risk has been choosen as a function of traffic. The method attempts also to take into account in someway the effect of future maintenance on the overlaid pavement. The overlay design method has the form of a Catalogue of overlay structures in which overlays are calculated once for all. For the overlay of old flexible pavements, the various old pavements have been classified in 36 cases, according the deflection and thickness of old pavements. The overlay thickness has been calculated for each of these cases and for several traffic classes. It has been found that for overlays with cement of slag treated base, the overlay thickness depends only on traffic and deflection of the old pavement; and that for overlays with bituminous base, the overlay thickness depends on traffic, deflection on the old pavement, and thickness of asphaltic concrete in the old pavement. A method is also given for the design of asphalt overlay of old pavement with cement treated (slag treated) base. Two cases must be considered: the cement treated base shows fatigue cracks but has kept its cohesion, or has lost its cohesion. For old pavements of that type, overlay thickness are always high. /Author/

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 557-588

Subject/Index Terms

Filing Info

  • Accession Number: 00170238
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Mar 29 1978 12:00AM