Micro-meso Mechanical Behavior Of Asphalt Mixtures Based On Locally Effective Properties

Asphalt mixtures are kinds of compounds which consist of aggregate with complexsurface properties, asphalt mortar with complicated rheological behaviors and voidsamong random distribution, its macro performance is relative with micro structures andmeso-scale distribution. It is remarkable that current design methods of asphalt mixturesare based on phenomenological theory, which just establishes relation between designindex and macroscopic performance of asphalt pavements, neglects the influencebetween mixtures’ micro-meso structural parameter and mixes properties. On the otherhand, on the basis of continuum mechanics and layered elastic theory, asphalt pavementstructural design method does not take complicated properties and micro structures,meso-scale distribution into consideration. During the pavement design, micro-mesostructural information is ignored. Therefore analysis of micro-meso propertiescontributes to build the relation with macroscopic performance.Firstly, raw materials properties of mixtures were obtained through laboratory tests,confirmed that all data met the requirement of standards. Asphalt mixture was dividedinto two main components (coarse aggregate and mortar) ignoring voids, on account ofstatic pressure resilience modulus and static creep experiments, mortar materialparameters were tested. Digital image processing technique was applied to gain blackand white images of different gradations, then gained and analyzed the feature indexesof coarse aggregate.Secondly, considered micro interface properties then established interfaces’ microstructural models of different asphalt mixes, designed and adopted pullout test toevaluate interface properties, damage parameters of CZM and XFEM were acquired.Comparatively analyzed FEM data of different interface CZM and XFEM modelsintegrated with VCCT then concluded the influencing rule between micro-mesostructures and anti-cracking capacity of interface, mortar.Finally, based on FEM modeling technique, analyzed uneven distributed under mesostructure of different asphalt mixtures. Homogenization of asphalt micro and mesostructure was completed based on moving windows technique and locally effectivematerial, which aimed at averaging the big gap between coarse aggregate and mortarwith respect to their elastic modulus. Through FEM analysis and operational test basedon digital image correlation in lab, the meso structural model was proved to be proper insome degree. Composite autocorrelation function was applied to collect structuralparameters, the different models of various gradations were conducted to describe therelation between original gradations and local effective material models, the structuralparameters influenced the compression, traction, shear resistance. Intended to research mechanical behavior under muti-scale of various asphalt mixes,discussed the bridge mechanism between muti-scale. Meso structural effective modelsnot only content detailed information of original structures but also locally homogenizethe big different material properties of two main components. According to FEManalysis, this kind of model could characterize the mechanical feature of macroscopicperformance in a certain extent. This model has some application value while used intoreal pavement performance evaluation.