| Author: | Li, Gaoyang |
| Title: | Multiscale modeling of asphalt materials' complex moduli based on steady-state dynamic method |
| Advisors: | Leng, Zhen (CEE) |
| Degree: | M.Sc. |
| Year: | 2019 |
| Subject: | Asphalt -- Additives Asphalt concrete -- Testing Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Civil and Environmental Engineering |
| Pages: | ix, 78 pages : color illustrations |
| Language: | English |
| Abstract: | Complex modulus is an essential parameter to describe the viscoelastic properties of asphalt materials. This research aims to find a more effective and accurate method to predict the complex moduli of asphalt materials at different length scales. To this end, the Steady-State Dynamic (SSD) method coupling with a random aggregate distribution algorithm was proposed to multiscale modeling of asphalt materials. To prove the effectiveness and accuracy of SSD method in predicting complex modulus, both wearing course mixture and stone matrix asphalt mixture with a maximum nominal aggregate size of 10 mm, namely WC10 and SMA10, which are respectively dense-graded and gap-graded material, were utilized in this research for experiments and modeling. In the first part, experiments were conducted to obtain the complex moduli at each scale including binder, mastic, fine aggregate matrix (FAM) and mixture. To do so, the complex moduli of asphalt binder, mastics, and FAMs were characterized by Dynamic Shear Rheometer (DSR) machine. For asphalt mixtures, the Universal Testing Machine (UTM) was used to perform the tests. In the second part, the test data obtained from previous experiments were used to construct the master curves and fit the Prony series models. Two viscoelastic models, Christensen-Anderson (CA) model and modified Huet-Sayegh (MHS) model, were selected to perform the construction of master curves. For asphalt binder and mastic, the CA model was utilized to describe the frequency domain response data. For FAM and asphalt mixture, the MHS model was used to construct the master curves. The fitting results of these two models with the master curves obtained from the experimental data show a good agreement. Then the constructed master curves were further fitted by the Prony series model to input the properties of asphalt materials into the finite element program ABAQUS for simulation. The last part of this research is the numerical simulation. In this part, three types of geometrical finite element models were developed firstly, including the homogeneous model, heterogeneous model without a coating layer and heterogeneous model with a coating layer, both heterogeneous models were developed by the random aggregate distribution algorithm in ABAQUS. In this research, the asphalt binder was simulated with the homogeneous model to verify the effectiveness of the SSD method in predicting the complex modulus of asphalt materials. For mastic, FAM and asphalt mixture, heterogeneous models were developed to consider the microstructure. Further, the heterogeneous models with a coating layer were developed to take the coating layer on the surface of the aggregate into consideration. Then, to predict the complex moduli of asphalt materials, the FE simulations based on the SSD method were performed in the ABAQUS platform. Results show that the SSD method can accurately predict the complex moduli of asphalt materials at each length scale. Moreover, the SSD method was compared with the conventional transient dynamic (TD) method, which proves that the SSD method can significantly improve the computational efficiency and accuracy of prediction. Therefore, the proposed method provides a better approach to predict the complex moduli of asphalt materials. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 5275.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 5.41 MB | Adobe PDF | View/Open |
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