Prediction of Rheological Properties of Asphalt Binder and Asphalt Mastic Containing Crumb Rubber Using Generalized Self-Consistent Micromechanical Model (GSCS)

Since the 1990s, micromechanical models have been used to predict mastic asphalt properties. However, a significant number of these models are deemed unsatisfactory in predicting the proper-ties of asphalt mastics due to their failure to account for the physical and chemical interactions between the bitumen and filler, as well as the interactions between filler particles. In this article, the generalized self-consistent scheme (GSCS) micro-mechanical model is investigated for its efficacy in predicting the complex shear modulus of modified bitumen with crumb rubber and asphalt mastics. The micro-mechanical model is founded on the mechanical properties of the constituent materials and their particle interactions. One base bitumen and two modified bitumens with crumb rubber at weight percentages of 10% and 15% were selected to produce asphalt mastics with two different filler volume ratios of 18% and 35%. The accuracy of the predictions was evaluated by comparing the relative difference between the experimental and predicted complex shear modulus curves using the GSCS model. The results demonstrate that the generalized self-consistent scheme model has satisfactory predictions for low filler volume ratios, but its accuracy is significantly influenced by frequency. Furthermore, as the filler percentage increases, the model error increases, and its reliability is compromised. Therefore, it is imperative to consider the chemical interaction between bitumen and filler, particularly modified bitumens and fillers, in developing models to address this inefficiency and problem.