Prediction of dynamic shear modulus of fine aggregate matrix using discrete element method and modified Hirsch model
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© 2019 Dynamic shear modulus of fine aggregate matrix (FAM) has a significant impact on the mechanical response of an asphalt mixture, and micromechanical computational models have proved to be suitable for predicting the modulus of the FAM and the asphalt mixture. However, the model programming is complicated and time-consuming, and it is difficult to be applied directly in pavement design. This study aims at developing a micromechanics-based model which can be used to predict the dynamic shear modulus of the FAM at a variety of frequencies and temperatures. The laboratory Dynamic Shear Rheometer (DSR) tests of asphalt mastics and the oscillatory torsional tests of the FAM are conducted at 7 angular frequencies and 5 temperatures to construct master curves. A three-dimensional discrete element model (DEM) of the FAM is developed to validate the dynamic shear modulus tests. The effects of volumetric and mechanical properties of individual constituents on the simulation results at different frequencies and temperatures are also investigated. After that, the modified Hirsch model is implemented to predict the composite modulus of the FAM. The results show that the DEM is a promising tool to analyze the dynamic shear modulus of the FAM. The modified Hirsch model predicts the dynamic shear modulus of the FAM successfully over a wide range of frequencies and temperatures.
author list (cited authors)
Zhang, Y., Ma, T., Luo, X., Huang, X., & Lytton, R. L.