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Mixedmode fracture behavior of asphalt mixture
based on discrete element method
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(1. School ofTransportation, Southeast University, Nanjing, Jiangsu 211189, China; 2. School of Civil Engineering, Central South University, Changsha, Hunan 410075, China; 3. School of Road Bridge & Harbor Engineering, Nanjing Communication Institute of Technology, Nanjing, Jiangsu 211188, China)
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Abstract To analyze the mixedmode fracture in asphalt mixture(AM) from microscopic view, according to the microscopic characteristics of AM, the asphalt mixture was divided into aggregate, asphalt mortar and air voids to determine the conversion relation between macroscopic and microscopic parameters, and the discrete element method(DEM) model was established with microstructure feature. The reliability of the predefined parameters of DEM model was verified by comparing the results of virtual model and laboratory test. According to the results of the virtual experiment for the prenotched beam samples with different mixmode cracking patterns, the propagation of cracks, the stress intensity at the tip of cracks and the displacements around the cracks were analyzed. The results show that the main factor for controlling fracture path is fracture mode followed by relative position of aggregates and cracks. With the increasing of cracking type II, the width of the fracture process zone becomes narrow, and the stress level is decreased with weakened softening character. The displacements on both sides of fracture are increased with the offset of precrack, which makes the material tend to brittle failure.
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Received: 07 August 2018
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