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The permanent deformation (especially rutting) is one of the most common failure of asphalt pavement, which seriously undermines the quality of highway service and is prone to induce cracks and other damage. Firstly, based on the laboratory Hamburg wheel tracking test, the AC-13 asphalt mixture virtual model was constructed through the particle flow code (PFC) of the three-dimensional discrete element method (3D DEM). Then, the virtual Hamburg wheel tracking test was performed to analyze at a mesoscopic level the deformation mechanism of the aggregate skeleton during the loading test, and the effects of temperature and pressure on the anti-deformation performance of asphalt mixture. The results demonstrated that the discrete element model can accurately simulate the rutting test of asphalt mixture, and the final relative error was below 10% in general. In addition, during the virtual Hamburg rutting test, the displacement of the aggregate in the Z-axis and X-axis directions increased with the growing numbers of loading, and there was a certain reciprocal movement of aggregate in the Y-axis direction. Moreover, the aggregate still maintained a high level of displacement at a certain depth from top to down inside the virtual specimen, indicating that the small depth of the asphalt pavement from the top to the bottom was the peak area where the structure suffered from shear.
Hui Wang; Zhenghui Zhou; Weilin Huang; Xinyu Dong. Investigation of asphalt mixture permanent deformation based on three-dimensional discrete element method. Construction and Building Materials 2020, 272, 121808 .
AMA StyleHui Wang, Zhenghui Zhou, Weilin Huang, Xinyu Dong. Investigation of asphalt mixture permanent deformation based on three-dimensional discrete element method. Construction and Building Materials. 2020; 272 ():121808.
Chicago/Turabian StyleHui Wang; Zhenghui Zhou; Weilin Huang; Xinyu Dong. 2020. "Investigation of asphalt mixture permanent deformation based on three-dimensional discrete element method." Construction and Building Materials 272, no. : 121808.
In order to investigate creep mechanism of asphalt mixtures from the mesoscopic level, a virtual dynamic creep test of asphalt mixture was conducted with two-dimensional discrete element method (DEM). Based on the probability theory and the Monte-Carlo method, a random generation algorithm was used to generate aggregate particles with irregular shapes. The virtual dynamic creep test, including the modeling of a virtual asphalt mixture specimen, the selection of contact models and mesoscopic parameters, and the realization of semi-sine wave intermittent dynamic loading, was simulated based on DEM. Then the simulation results were verified via the experimental dynamic creep test. It is demonstrated that the discrete element model effectively simulated the dynamic creep test, in which the relative error is less than 10% in general. During the simulation test, the contact force in the asphalt mixture was evenly distributed at the beginning of loading, but part of the contact bond was broken, and then redistributed and stress concentration appeared in the failure period. In addition, with the increase of temperature or contact pressure, the axial strain of asphalt mixture increased, and the resistance to permanent deformation decreased, which is consistent with law of the laboratory test. Moreover, the relation between the elastic modulus and axial strain in Burgers model indicates that the modulus of Burgers model is closely correlated with permanent deformation of asphalt mixture.
Hui Wang; Weilin Huang; Junjie Cheng; Gang Ye. Mesoscopic creep mechanism of asphalt mixture based on discrete element method. Construction and Building Materials 2020, 272, 121932 .
AMA StyleHui Wang, Weilin Huang, Junjie Cheng, Gang Ye. Mesoscopic creep mechanism of asphalt mixture based on discrete element method. Construction and Building Materials. 2020; 272 ():121932.
Chicago/Turabian StyleHui Wang; Weilin Huang; Junjie Cheng; Gang Ye. 2020. "Mesoscopic creep mechanism of asphalt mixture based on discrete element method." Construction and Building Materials 272, no. : 121932.
Asphalt migration is one of the significant detrimental effects on asphalt pavement performance. In order to simulate the state after the occurrence of asphalt migration amid asphalt pavement layers and further investigate the effects of asphalt migration on the dynamic modulus of asphalt mixture, samples with different asphalt contents layers were firstly separated into the upper and lower half portions and then compacted together. By conducting the dynamic modulus test with the Superpave Simple Performance Tester (SPT), the variation laws of the dynamic modulus (|E*|) and the phase angle (δ) at different testing temperatures and loading frequencies were analyzed in this paper. Further, the dynamic modulus and the stiffness parameter (|E*|/sinδ) at the loading frequency of 10 Hz and testing temperature of 50 °C were illustrated. Simultaneously, the master curves of the dynamic modulus and phase angle of asphalt mixtures under different testing conditions were constructed to better investigate the effects of asphalt migration on the dynamic modulus by means of Williams–Landel–Ferry (WLF) equation and Sigmoidal function. Results show that, after the asphalt migration, the dynamic modulus of asphalt mixtures increase with the increasing loading frequency while they decrease with the increasing testing temperature; the dynamic modulus and the stiffness parameter are the highest when asphalt mixtures have the optimum asphalt content layers, and then decrease with the incremental difference of asphalt content in the upper and lower half portions. Besides this, different from the master curves of dynamic modulus, the master curves of phase angle firstly increase with the increase of loading frequency to the highest point and then decrease with the further increase of loading frequency and are not as smooth as that of dynamic modulus. It can be concluded that the asphalt migration has compromised the mixture’s mechanical structure, and the more asphalt migrates, the weaker the mechanical properties of asphalt mixture will be. Additionally, based on the shift factors and master curves in the time–temperature superposition principle (TTSP), the effects of asphalt migration on the dynamic modulus and the variation laws of the dynamic modulus of asphalt mixture after the occurrence of asphalt migration can be better construed at the quantitative level.
Hui Wang; Shihao Zhan; Guojun Liu. The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture. Applied Sciences 2019, 9, 2747 .
AMA StyleHui Wang, Shihao Zhan, Guojun Liu. The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture. Applied Sciences. 2019; 9 (13):2747.
Chicago/Turabian StyleHui Wang; Shihao Zhan; Guojun Liu. 2019. "The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture." Applied Sciences 9, no. 13: 2747.
According to the characteristics of asphalt pavement, a kind of nano-TiO2 photocatalytic coating was prepared by using the emulsified asphalt as the carrier. All of its properties met the technical requirements. An exhaust gas degradation test device and its test steps were developed. The evaluation indexes, cumulative degradation rate, and degradation efficiency, were put forward. From the two aspects of the nano-TiO2 content in photocatalytic coatings and the spraying amount of photocatalytic coatings in the surface of slabs (300 mm × 300 mm), the exhaust gas degradation effects, the performances of skid resistance, and the water permeability of asphalt mixture were analyzed. The test results showed that the cumulative degradation rate of exhaust gas was better when nano-TiO2 content was increased in the range of 0–8% and the spraying amount was changed in the range of 0–333.3 g/m2. In practical engineering applications, the anti-skid performance of asphalt pavement can be satisfied when the spraying amount of photocatalytic coating was limited to under 550 g/m2. The spraying amount of nano-TiO2 photocatalytic coating had little effect on the water permeability of the asphalt mixture. Therefore, 8% nano-TiO2 content in the coating and a 400 g/m2 spraying amount were finally recommended based on the photocatalytic properties, as well as for economic reasons.
Hui Wang; Ke Jin; Xinyu Dong; Shihao Zhan; Chenghu Liu. Preparation Technique and Properties of Nano-TiO2 Photocatalytic Coatings for Asphalt Pavement. Applied Sciences 2018, 8, 2049 .
AMA StyleHui Wang, Ke Jin, Xinyu Dong, Shihao Zhan, Chenghu Liu. Preparation Technique and Properties of Nano-TiO2 Photocatalytic Coatings for Asphalt Pavement. Applied Sciences. 2018; 8 (11):2049.
Chicago/Turabian StyleHui Wang; Ke Jin; Xinyu Dong; Shihao Zhan; Chenghu Liu. 2018. "Preparation Technique and Properties of Nano-TiO2 Photocatalytic Coatings for Asphalt Pavement." Applied Sciences 8, no. 11: 2049.
Fatigue is considered a major pavement structural distress and an important part of a performance-based mix design. Currently, the fatigue model of asphalt mixture, especially the mixture incorporated with fibers, is not perfect. In this paper, the central-point bending fatigue test was conducted by constant strain mode with MTS apparatus. The fatigue performance and model of polyacrylonitrile (PAN) fiber-reinforced asphalt mixture produced with different fiber contents and asphalt contents were reported. The results indicated that the fatigue life of fiber reinforced mixture was higher than the reference one. The effects of fiber contents and asphalt contents on fatigue life were discussed. The mechanism of an optimum fiber content for the fatigue life in the fiber reinforced asphalt mixture was explained. The statistical analysis of variance (ANOVA) method and regression method were used to evaluate the effects of fiber content, strain level, and volumetric parameters, etc. on the fatigue life of an asphalt mixture. This paper presents a new fatigue performance model of a PAN fiber-reinforced asphalt mixture, including the fiber content, tensile strain, mixture initial flexural stiffness, and voids filled with asphalt (VFA). Compared to the earlier fatigue equations, the accuracy of the new fatigue model with the fiber content is improved significantly according to the statistical analysis results. Meanwhile, the model can preferably reveal the effect of fiber content, strain level, initial stiffness, and VFA on fatigue life.
Hui Wang; Zhen Yang; Shihao Zhan; Lei Ding; Ke Jin. Fatigue Performance and Model of Polyacrylonitrile Fiber Reinforced Asphalt Mixture. Applied Sciences 2018, 8, 1818 .
AMA StyleHui Wang, Zhen Yang, Shihao Zhan, Lei Ding, Ke Jin. Fatigue Performance and Model of Polyacrylonitrile Fiber Reinforced Asphalt Mixture. Applied Sciences. 2018; 8 (10):1818.
Chicago/Turabian StyleHui Wang; Zhen Yang; Shihao Zhan; Lei Ding; Ke Jin. 2018. "Fatigue Performance and Model of Polyacrylonitrile Fiber Reinforced Asphalt Mixture." Applied Sciences 8, no. 10: 1818.