Experimental on indirect tensile test for asphalt mixture based on discrete element simulation and fractal dimension(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2019年06期
- Page:
- 39-48
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Experimental on indirect tensile test for asphalt mixture based on discrete element simulation and fractal dimension
- Author(s):
- LI Xuelian; LIU Xueying; LYE Xinchao; YE Junhong
- (1. School of Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, Hunan, China; 2. National Engineering Laboratory for Highway Maintenance Technology, Changsha University of Science and Technology, Changsha 410114, Hunan, China; 3. China Railway Major Reconnaissance and Design Institute Co.,Ltd., Wuhan 430050, Hubei, China; 4. Guangxi Transportation Research & Consulting Co., Ltd., Nanning 530007, Guangxi, China)
- Keywords:
- road engineering; asphalt mixture; crack; discrete element; fractal dimension; indirect tensile
- PACS:
- -
- DOI:
- -
- Abstract:
- In order to investigate the evolution process of internal damage and the law of crack propagation in asphalt concrete, the indirect tensile test of asphalt mixture was carried out in the laboratory by using MTS universal test machine. The force, displacement and time data during the test were obtained. At the same time, the specimens were scanned by industrial CT equipment, and the scanning images before and after the indirect tensile test were obtained. In addition, the constituents such as asphalt mortar, coarse aggregate and air void were extracted by digital image processing techniques such as grayscale, image enhancement and threshold segmentation. Then, the discrete element model was built based on the constituents information, and indirect tensile simulation test was carried out. the development of cracks of the model was observed. The load, displacement and number of fractures of the joints Ncb were obtained. Finally, the development of the cracks was analyzed. The characteristics of loaddisplacement curves in the simulation test and that in the laboratory test were compared. Based on Ncb, the internal microscopic damage variable Dm was present, the boxcounting dimension variable Dc was proposed based on the crack image of the whole specimen, then the relationship between meso damage degree and crack development was established. The results show that the strength of the simulation test and that of the indoor test is very close. The trends of the loaddisplacement curve and the distribution law of these two tests are similar, and the feasibility of simulation test is verified. The development of cracks can be divided into four stages, in clude initiation, development, interconnection and after interconnection. Dm is lower during the initiation and expansion stages but higher during the interconnection stage. In addition, Dc is also closely related to the fractal characteristics of the crack. Dc changed monotonously in each stage of the crack, and the trend is obvious. In short, according to Dc, the development of the crack can be determined. Therefore, the mesoscopic damage inside the asphalt concrete can be evaluated indirectly. It also provides a new idea for pavement damage evaluation, which can be used to evaluate the degree of pavement damage according to the pavement crack condition. 3 tabs, 14 figs, 28 refs.
Last Update: 2019-12-19