An investigation was made of possible direct correlation between deflection and the deterioration of roads, deterioration characterized primarily by the development of rutting on the wheel paths. The experimental programme designed to relate deflection measured by the Benkelman Deflection Beam to pavement condition and traffic is briefly described. The preliminary information presented at the last Conference has been greatly extended and confirm strongly defined relationships between deflection measured early in the life of the road and the onset of critical conditions defining the need to strengthen. When combined with further similar relations known to exist between critical deflections and the traffic carried, design charts for predicting unexpired pavement life can be drawn up: these are presented for the main types of pavement. A system for predicting pavement life and designing overlays from this type of information obtained on the the road by surveys using the Deflectograph and the Benkelman Deflection Beam is briefly described, with reference to other published work. The latest development in the design procedure is a computer programme capable of treating the variability of deflection in a consistent manner in such a way as to eliminate the risks of localised early failure or over design in the strengthened pavement. Assessment of successive 100m lengths of road on a moving average principle is used to define minimum cost solutions which are then used by the engineer as the basis for designs which take into account engineering constraints. Deflection surveys carried out on a number of normal roads having a range of base types are compared with the predictions of the design charts presented. Samples are given of both new construction and strengthened pavements; one example where the design life of an overlay has now expired is considered in are detail. /Author/

Media Info

  • Features: Figures; References;
  • Pagination: p. 629-648

Subject/Index Terms

Filing Info

  • Accession Number: 00170240
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Mar 29 1978 12:00AM