The deformation of an idealised pavement composed of linear visco-elastic materials subject to a pulse load is analysed as a means of assessing the reliability of an approximate method of computing the permanent displacement of the surface of a pavement, based on the use of independently computed stresses in association with measured deformation properties. It is shown that, in the linear visco-elastic system, the permanent deformation is independent of the elastic properties of the materials, and depends only on their viscous properties, and that the permanent deformation in such a pavement model can be computed using an 'elastic' program supplied with values of the deformation parameters rather than the elastic constants. The results given by the visco-elastic analysis and by the approximate method in a few cases are compared. In absolute terms, the approximate method seems unreliable, but it may give a reasonably reliable assessment of the relative performance of pavements. (Author/publisher)
Samenvatting