Study On Accumulation Behavior And Skeleton Structure Of Particle Pavement Materials Based On Meso-mechanics

Asphalt mixture is composed of discrete rigid aggregate and continuous viscous medium.From the volume composition,aggregate occupied the main part and accounting for about 90% of the asphalt mixture.The reasonable volume composition not only significantly improved the mechanical properties of asphalt mixture,but also balanced the complex contradiction of multiphase composites.From the meso point of view,the aggregate particles are dispersed randomly in asphalt mortar medium,and they will be squeezed and rubbed.Therefore,the physical,mechanical properties and meso interaction between aggregate components have great influence on the mechanical properties of asphalt mixture.However,the existing asphalt mixture design methods are mostly based on empirical methods,and they are overemphasis on the role of asphalt binder.The systematic study and analysis of dominant aggregate are neglected.With the research methods help of basic particulate matter theory,firstly,the aggregate spatial distribution model is put forward based on Monte Carlo method.The complex meso interaction between aggregates,such as friction,contact and interlock were analyzed,and the discrete element model applied to aggregate at meso simulation was established.The relationship between meso parameters of the model and penetration process was discussed.And results show that the sensitivity of particle friction coefficient and porosity is much larger than the particle contact stiffness ratio in the penetration process.The reliability of simulation test is proved by the existing experimental results.Secondly,the evaluation index of CBR and VCA are adopted to analyze the continuous gradation and gap gradation of aggregate mixture gradation rules based on the stage filling theory numerical test.The bearing capacity of aggregate mixture can be characterized by penetration resistance curve under same penetration displacement.And on this basis,the optimum gradation was put forward.Finally,the initial particle structure obtained by random packing model was analyzed statistically.After discrete dynamic calculation under gravity loads,the mean coordination number of single particle size loose particles increased with decreased void ratio.The overall mean coordination number of mixed size spherical granular changes in a small scope and basically a constant,which agrees with the literature measured results.The results show that the accumulation behavior of particles in gravity field can be better simulated by the proposed numerical simulation method in this paper.And on this basis,the meso-mechanical response of aggregate mixture was analyzed in penetration process.The network of force chain structure and change process of mean coordination number were observed.The migration and evolution law of aggregate particles was obtained by the varied particle displacement vector field.Research shows that,with the help of research methods of PFC3 D platform to pile up and stable skeleton process observation particles convenient and effective pavement materials,lay the foundation for particle migration and force stability Lian further research on complex shape behavior.