Bending And Pulling Of Asphalt Mixtures Considering Coarse Aggregate Morphology Using Discrete Elements

Asphalt mixture bending test is a common indoor test used to study the mechanical properties of asphalt mixture bending failure at specified temperature and loading rate.At the same time,coarse aggregate has a great impact on the mechanical properties of asphalt mixture because of its large mass proportion in asphalt mixture,the traditional laboratory test is limited by its test time and the analysis of micro results.Combined with three-dimensional laser scanning technology and discrete element simulation method,this paper studies the relationship between coarse aggregate morphology and flexural tensile failure of asphalt mixture.This paper tests of the same batch of coarse aggregate with different revolutions are carried out to obtain the coarse aggregate with different edges and corners,and the coarse aggregate of this batch is classified according to its shape.The three-dimensional laser scanning technology is used to scan all kinds of coarse aggregates,combined with Geomagic Studio software,the contour models of different forms of coarse aggregates are constructed through point cloud data processing and surface fitting.The current evaluation methods of coarse aggregate morphology are summarized.The ellipsoid method and sphericity method are used to evaluate the angular characteristics and shape characteristics of coarse aggregate respectively,and the coarse aggregate profile is filled by using the filling function of EDEM software to obtain the coarse aggregate template.According to the mass content of each component of the mixture calculated under the specific porosity and asphalt aggregate ratio,the virtual trabecular specimen is generated in EDEM and simulated by bending test.The simulation results are verified according to the indoor test results.Using EDEM software,the effects of test loading rate,internal bonding characteristics of mixture and the shape of coarse aggregate on the flexural tensile properties of mixture are studied.At the same time,the crack propagation path,aggregate stress and internal bonding changes of asphalt mixture with different angular coarse aggregate are analyzed.