Development of In-Situ Hirsch Model for Prediction of Dynamic Modulus of Asphalt Layers

Mechanistic–Empirical Pavement Design Guide (MEPDG) uses dynamic modulus for flexible pavement design and rehabilitation. This parameter could be defined as the viscoelastic property of asphalt materials. Mechanistic–Empirical Pavement Design Guide (MEPDG) uses results of both Falling Weight Deflectometer (FWD) and laboratory dynamic modulus predictive models for determination of dynamic modulus of in-service asphalt layers. In this research, ten asphalt pavement sites were selected in Khuzestan and Kerman provinces in Iran. Field and laboratory testing were performed and dynamic modulus of in-service asphalt layers was determined. Hirsch predictive model for dynamic modulus of asphalt mixes was calibrated and new model was developed for predicting in-situ dynamic modulus of asphalt layers. Performance evaluation and validation of this new model showed very good correlation between predicted and measured values with high prediction accuracy and low prediction bias.Keywords: Dynamic Modulus of Asphalt Layers, FWD, Dynamic Modulus Predictive Models, Hirsch Model, Mechanistic–Empirical Pavement Design Guide (MEPDG).