Relating full-scale pavement rutting to laboratory permanent deformation testing

The study concerns the full-scale testing of a low-volume road pavement using the heavy vehicle simulator (HVS-Nordic) and the complementary testing of the same materials in the laboratory, especially using a repeated load triaxial test. The objective of the study was to develop an analytical method of calculating the permanent deformations on the basis of the stresses calculated by a finite element program, using input data obtained from laboratory assessments. It was found that the growth of permanent deformation as a function of load repetitions can be estimated using Sweere's Formula, but that an allowance for the stress state needs to be made. This was achieved by allowing a stress dependency in Sweere's parameter b, as a function of the failure ratio q/q f. It is shown that this can be estimated with a simple linear function according to the HVS and laboratory results. The resilient moduli needed for the finite element calculations were back-calculated from in situ loading tests. Both resilient and permanent deformations proved to be bigger in the HVS tests than those suggested from the laboratory tests.