The present paper discusses the application of a high-cycle accumulation (HCA) model originally developed for sand for the prediction of permanent deformations in unbound granular material (UGM) used for base and subbase layers in pavements. Cyclic triaxial tests on pre-compacted samples of an UGM have been performed in order to validate and calibrate the model. The stress amplitude, the initial density and the average stress were varied. The test results are compared to those of air-pluviated samples of sand (subgrade material). Some significant differences in the behavior of both materials under cyclic loading are outlined. It is demonstrated that the functions describing the intensity of accumulation can be maintained for UGM with different material constants, but that the flow rule must be generalized in order to describe anisotropy. Recalculations of the laboratory tests show a good prediction of the modified HCA model.
