Structure And Performance Of High-performance Graded Crushed-stone Base Course Based On The Interaction Between Granular Materials

Based on the interaction between granular materials, the indoor test, finite element model and discreteelement model are used to study the structure and properties of high performance graded crushed stonebase in macro-scale and macro-scale.To satisfy the self-lock condition between granular materials, gradation design method is proposed bygrading fill test and the theory of maximum density curve. The influence from7common grading designmethods on the density and void fraction are analyzed, and from the comparative analysis result, I methodand grading fill method could make the graded gravel has high density and rational void fraction.Permeability of graded gravel with various void content are tested, and the minimum void ratio isproposed. By the dynamic cyclic tri-axial test, the maximum void ratio is determined based on the axialplastic strain demand. The CBR of graded gravel within the rational void ratio scope are tested to confirmthe excellent mechanical performance, and the gradations of high performance graded gravel arerecommended. The stability of graded gravel under variable load conditions is evaluated.Using the performance parameters form indoor tests, the elastic-plastic continuum finite elementmodel is established, and the transmission and distribution of the stress and deformation in macro-scale areanalyzed. Using the homogenization theory method, the mechanical properties and deformationcharacteristics in macro-scale are related with the contact force between particles and displacement ofparticles in micro-scale, and the multi-scale correlation method of graded crushed stone material is putforward.Three-dimensional elastic-plastic finite element model is set up, in different load level, structure,layer thickness, structure layer modulus, the stress indexes of asphalt pavement with graded gravel astransition layer or base layer are analyzed, and the regression equations of stress indexes are established.Based on the minimum stress index, the structure combinations of asphalt pavement with graded gravel astransition layer or base layer are proposed. Simulation models with top-down crack in surface layer andbottom-up crack in base layer are established respectively, the stress indexes are calculated and comparedwith the initial value, to analyze the influence on the crack propagation from the graded gravel transitionlayer.From the experimental study and the simulation model analysis, the design goals, design index,design criteria, and design method of high performance graded gravel with high strength, high deformationresistance ability and good permeability are proposed. And the construction technology requirements inpreparation, transportation, paving and compaction are proposed.