Study On The Composition Structure Characteristics Of Mineral Mixture Based On Packing Theory

In asphalt mixture,about 90% of the total volume is aggregate that plays an important role in the engineering characterist ics of asphalt mixture.However,in the current asphalt mixture material design procedures,the phenomenological method is widely used to study the macro properties of materials,ignoring the nonuniformit y and complexity of the composition of asphalt mixture.According to the packing structure of aggregate mixture composed by typical bulk particles,the structure characteristics of mineral mixture were studie d and analyzed based on the packing theory in this study,combining the test and simulation on discrete element method.The technology of X-ray CT tomographic scanning,image processing and PFC simulation based on discrete element method(DEM)were used in the process of research.First of all,combined with X-ray CT tomographic scanning and image processing technology,compare PFC particle accumulation model and the realistic model and a optimization process were conducted to the PFC particle accumulatio n model.Then test the consistency of result between PFC particle accumulation mode and realist ic model.Secondly,analyzes the effects of structure characterist ics of spherical aggregates on the accumulat ion system composition structure,from the two aspects of morpho logical features and morphology features that were separately represented by needle ratio and aggregate surface frict ion coefficient.The next,according to force chain theory and filling theory,three typical mineral mixtures(AC16,OGFC16,SMA16)are selected to study,the skeleton characteristics of coarse aggregate and the filling effect of fine aggregate change the proportion of fine to coarse aggregate in gradation.The sharing ratio of the skeleton force aggregate of each size of aggregate were analyzed.Taking the number of fine particles around coarse aggregate as an index,the filling effect of fine aggregate on grading system was analyzed.By using the Fourier series approximation method(FSA)on aggregate accumulat ion of composition str ucture analysis,force analysis the of normal contact force principal stress direction and anisotropic distribution of component anisotropic structure of the typical mineral mixture were studied.Then,regarded the graded particle accumulation as a system,using Partial Least Squares(PLS)multiple linear regression method,the correlation of the internal system of coarse aggregate skeleton characteristics and fine aggregate filling effect and correlation between the skeleton force and the particle composit ion were studied,analyzing the key types of particle of the mineral mixture can significant ly influences skeleton structure.Finally,considering the geometric characteristics and aggregate gradation,the generation and accumulation were realize by a Matlab-PFC 2D interactive program that was developed specifically.The effect of morphological characteristics and morphological characteristics on the densification degree and skeleton structure o f mineral mixture were analyzed.The significance test was carr ied out by means o f variance analysis.This study,based on the theory of accumulation,were executed using X-ray CT tomographic scanning and image processing technology,PFC discrete element method simulation and computer programming on the basis of the a lgorithm,studied and analyzed the composition structure evaluation method and influencing factors of mineral mixture on the mineral mixture,provides a good reference for the fo llowing design and performance detection of asphalt mixture.