| In recent years,Our country has made a series of brilliant achievements in the field of transportation,especially in the field of highway construction.However,with the increase of the use time of highway,a series of prominent problems appear slowly,especially under the repeated wheel pressure of heavy-duty vehicles,asphalt mixture pavement has not reached the design service life and is forced to withdraw from service due to fatigue damageThe traditional fatigue failure mode of asphalt pavement is mainly bending fatigue failure of asphalt pavement,which mainly forms bottom-up cracks.However,with the increase of overloaded vehicles and the use of semi-rigid base,the main form of cracks has become top-down shear fatigue failure.Therefore,shear fatigue has become the main failure mode of asphalt pavement.Therefore,this paper uses CT scanning technology and digital image processing program of Sub-Microstructure Analysis System of Asphalt Concrete(MASAC)to obtain the internal specific information of asphalt mixture specimens.Based on the three-dimensional discrete element method,the virtual three-dimensional discrete element model of asphalt mixture specimens is established by using software PFC3D,and the shear fatigue test value of asphalt mixture is further calculated on the basis of the obtained model.The simulation is then validated by the results of laboratory tests to explore the effects of different gradation types,different asphalt-aggregate ratios,different temperatures and other factors on the fatigue life of asphalt mixtures.The results show that aggregate gradation,asphalt-aggregate ratio,temperature,air voids,loading frequency and so on have an impact on the fatigue life of asphalt mixtures;the virtual shear fatigue test of asphalt mixtures established by three-dimensional discrete element software PFC3D is effective and feasible in simulating the uniaxial repeated penetration test of asphalt mixtures,and the effect is outstanding. |
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