Browsing by Author "Hendrickson, Rebecca"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    A Mechanistic Design Approach for Graphite Nanoplatelet (GNP) Reinforced Asphalt Mixtures for Low-Temperature Applications
    (Minnesota Department of Transportation, 2018-01) Le, Jia-Liang; Marasteanu, Mihai; Hendrickson, Rebecca
    This report explores the application of a discrete computational model for predicting the fracture behavior of asphalt mixtures at low temperatures based on the results of simple laboratory experiments. In this discrete element model, coarse aggregates are explicitly represented by spheres, and these spheres are connected by bonds representing the fine aggregate mixture, a.k.a. FAM, (i.e. asphalt binder with the fine-size aggregates). A literature review examines various methods of computational modeling of asphalt materials, as well as the application of nanomaterials to asphalt materials. Bending beam rheometer (BBR) tests are performed to obtain the mechanical properties of the fine aggregate mixture (FAM) at low temperatures. The computational model is then used to simulate the semi-circular bend (SCB) tests of the mixtures. This study considers both the conventional asphalt materials and graphite nanoplatelet (GNP) reinforced asphalt materials. The comparison between the simulated and experimental results on SCB tests shows that by employing a softening constitutive model of the FAM the discrete element model is capable of predicting the entire load-deflection curve of the SCB specimens. Based on the dimensional analysis, a parametric study is performed to understand the influence of properties of FAM on the predicted behavior of SCB specimens.
  • Thumbnail Image
    Item
    A Mechanistic Design Approach for Graphite Nanoplatelet Reinforced Asphalt Mixtures for Low Temperature Applications
    (2017-05) Hendrickson, Rebecca
    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.