Validation of a plastic deformation model for UGMs using accelerated pavement test results

The paper presents the results of a project aimed at investigating the deformation behaviour of unbound granular materials in pavement structures. In particular, the validation of a laboratory-based deformation model with results of accelerated pavement tests undertaken at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF) in Christchurch, New Zealand will be described in detail. A total of 11 different pavements were tested at CAPTIF at three different loads where the asphalt surface thickness was 25 mm. The experimental results from CAPTIF tests were compared with those from pavement modelling performed with ReFEM 3D-Finite-Element Program incorporating the DRESDEN-Model, which was verified and calibrated in Repeated Load Triaxial (RLT) tests. The plastic model that was developed on the basis of the laboratory tests assumed that the plastic deformation behaviour is a volume constant process. However, the plastic basecourse deformation profiles measured at CAPTIF shows that the plastic deformation behaviour is not totally a complete volume constant process. This effect was incorporated into the finite element program to account for the proportion of the volume constant and non-volume content plastic deformations. Overall, a good agreement between the measured and calculated plastic basecourse strains was achieved.