Research On Three Dimensional Numerical Simulation Of Asphalt Mixture Based On CT Images

With the appearance of CT technology, the combination of digital images andnumerical simulation may be provided possible, overcoming the limitations oftraditional methods, thus the unnecessary tests work are minimized. Now the study ismainly concentrated on the internal structure of asphalt mixture of quantitative orqualitative analysis based on the sample and one or several2D section, and using digitalimage processing to achieve the two-dimensional numerical model. This approach hassome limitations, and based on the specimens of true3D micro distribution model ofnumerical simulation test is more less, but the asphalt mixture is a kind ofinhomogeneous, anisotropic multiphase mixture material, its microscopic structuremainly comprises an aggregate, asphalt mortar and voids, macroscopic structuredestruction is the microstructure changes of accumulation of external performance, themacroscopical and microcosmic combine research have important significance.This paper is based on asphalt mixture performance of special materials, with theaid of CT scanning technique nondestructive Marshall test piece of asphalt mixture indifferent layers of the internal structure of the digital image, and the study analysis airvoids and distribution characteristics based on image processing, the result shows that,the air voids at two ends are bigger than that at the middle of layers, which confirmedthat the micro structure of asphalt mixture specimen is not uniform, then,thesignificance of the calculation result difference of air voids of specimen was statistical,the air voids of CT images can be used as the real air voids value of specimen, it isproved that the image processing is accurate and reliable.Based on MATLAB, the asphalt mixture is divided into three part using thetwo-peak method values, and to realize the three-dimensional reconstruction of asphalt mixture, and the reconstruction of the image information is introduced into a largecommercial FEM software ANSYS, establishing that consist of aggregate, voids andasphalt mortar. Asphalt mixture of three-dimensional microscopic structure finiteelement model, the generated model is more close to the asphalt mixture the realstructure, and then using ANSYS software calculation functions, and input the differentmaterial property values of finite element simulation, the results of numericalcalculation and splitting test physical test result are compared, show that the numericalsimulation is reasonable, engineering test is putted a strong basis.