Rigorous computations of the permanent deformation in pavements by methods which satisfy all the necessary equations of equilibrium, compatibility and material behaviour are difficult and extremely time-consuming, so that simpler approximate methods are normally used. The implications of one such approach, which is in common use, are discussed. The further simplication is often made that in the computations, a moving load can be replaced by a pulse load, but the results of computations made by this separative method for pulse moving loads, using both linear and various non-linear deformation laws, lead to the conclusions that this approximation can result in serious distortions of the assessment of the relative contribution to the total surface displacement from the individual layers. Because of several doubts and difficulties associated with the use of separative approximations, the permanent deformation in a linear visco-elastic model of a pavement is discussed. It is shown that the permanent deformation in such a structure depends only on the deformational properties of the layers, and not at all on their elastic properties; this is in total conflict with the separative approach. It is concluded that to obtain physically reasonable results by either the separative approximation or a visco-elastic approach requires a knowledge of the deformation properties at low as well as at high stresses. /Author/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 540-554

Subject/Index Terms

Filing Info

  • Accession Number: 00170237
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Mar 29 1978 12:00AM