A Mechanistic Design Approach for Graphite Nanoplatelet Reinforced Asphalt Mixtures for Low Temperature Applications

Abstract

This thesis explores the application of a widely used commercial discrete computational model (PF3D) for predicting the fracture behavior of asphalt mixtures at low tem- peratures using input parameters from simple experiments. In this discrete element model, coarse aggregates are explicitly represented by spheres, which are connected by bonds representing the fine aggregate mixture (i.e. asphalt binder with the fine-size aggregates). Bending beam rheometer tests are performed to obtain the mechanical properties of the fine aggregate mixture (FAM) at low temperatures. The model is then used to simulate the semi-circular bend (SCB) tests. The comparison between the sim- ulated and experimental results on SCB tests shows that the PF3D model could predict the peak load and post peak behavior of the SCB specimens if an appropriate scaling relation for the strength of FAM is taken into consideration. The post-peak behavior of the SCB specimens can only be captured by taking into account the energy required to fracture one bond which can not be directly obtained from experiments on the FAM and is a fitting pararmeter. A parametric study is performed to understand the influence of different model parameters of the PF3D on the predicted behavior of SCB specimens.