Calibration studies

Parameters for the different models used in the incremental recursive design method have been determined through calibration studies, primarily using the California Heavy Vehicle Simulators (HVSs) (Ullidtz et al. 2007) but also some test track data (Ullidtz et al., 2008). Calibration of model parameters is an ongoing activity. The following papers on calibration are available: HVS calibration TRB 2008 and APT2008, WesTrack calibration AAPT 2008 and APT2008, Reflection cracking 6th-RILEM 2008 and APT2008,

The calibrations are normally done in two steps. First the pavement response calculated during the CalME simulation is compared to the measured response. The pavement response is used to predict the performance, in terms of permanent deformation and damage. It is essential that the calculated response is not too different from the actual, measured response, otherwise the calibration effort is without any value. The calibration studies till now have made use of resilient deflections measured using a Road Surface Deflectometer (RSD, similar to a Benkelman beam),Multi Depth Deflectometers (MDDs, which records both resilient and permanent deflections at several depths in the pavement structure) and/or a Falling Weight Deflectometer (FWD). Getting the pavement response correct involves the models for predicting the moduli of the materials and how they change with climate, damage and aging.

Once the CalME simulation can predict the pavement response for the whole duration of the experiment, then the models for permanent deformation can be calibrated.

Initial model parameters are derived from laboratory tests or from in situ tests such as FWD or Dynamic Cone Penetrometer (DCP). Damage function parameters are determined from laboratory fatigue testing (four-point bending, constant strain) and RSST-CH.

Materials that have been used in calibration studies are preceded by "Cal " in the Materials table of the database.