This paper is to be considered as an attempt to develop a generally applicable method for calculating the permanent deformation of bituminous layers due to viscous flow. Using a computer program based on linear, elastic multi-layer theory, the stress/strain distribution in a road under a wheel load can be calculated. This permanent deformation in one layer caused by the passage of one wheel is calculated assuming viscoelastic properties characterized by a Maxwell element. The total rut depth is obtained by summing up the irreversible deformations of all viscoelastic layers. It is important to consider the viscosity of the dashpot as a time dependent value increasing with the number of loadings. Thus, the phenomenon of "consolidation" taking place in asphaltic layers under traffic can be described. The material characteristics are derived from an unconfined compression creep-test which is described in this paper. The following conditions which influence rutting are taken into account: temperature distribution, number and amount of wheel loadings, transverse distribution of wheel passages, and speed of vehicles. The proposed method can be used to evaluate the mechanical properties of bituminous mixtures required to resist traffic forces under different climatic conditions. The validity of this method is shown by comparing the results with measurements made on a Swiss test-road since 1972. The effect of consolidation is shown by comparing the mechanical properties of field core specimens from bituminous layers from the normal lane and from the passing lane. /Author/

Media Info

  • Features: Figures; References;
  • Pagination: p. 497-508

Subject/Index Terms

Filing Info

  • Accession Number: 00170233
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM