Numerical Imitation On Cracking In Cement Concrete Based On Meso-Scale

Concrete is considered as a three-phase composite material consisting of aggregate,mortar matrix and the interfacial transition zone (ITZ) between them, and the macro-levelmechanical properties are decided by properties of material, ITZ and meso-mechanics. Atpresent, most mechanics properties of concrete material are researched on the basis ofexperiment. Nonetheless, the experiment sometimes does not work because of the limitationof the experimental condition, environment and the material itself.In recent years，numerical simulation has become a third investigation method besidesexperimental and theoretical study. In this paper，much effort is made on numericalsimulation on meso-scopic level.In the paper, According to the given testing size, aggregate gradation, mix proportion,random distribution feature of aggregate and the optimal gradation formula. The randomdistribution of aggregation specimen is generated by Monte-Carlo method. Throwingprogram of aggregates for two-dimension and three-dimension concrete specimen is madeby the second development of ABAQUS software. By batch commands scheme andgradually mesh generation method, the aggregate elements，the interface elements and thematrix elements are reasonably generated. In the same calculation precision of the premise,the gradually mesh generation method has high fasten calculate ability than mapped meshmethod because of less grid numbers, especially for three-dimension meso-finite elementmodel.Based on the application of random aggregate distribution meso-finite element model，kinds of typical numerical experiments such as uniaxial tensile test, splitting test anduniaxial compress test have been made.Rather than cracking initiation and crackingpropogation, as well as failure patterns and carrying capacity are simulated. The mechanicsparameters such as the tensile strength, the splitting tensile strength, the compressivestrength are acquired and deduced by the ultimate bearing capacity and the geometry size of concrete sample. In the end of this paper, the random aggregate model is expanded intothree-dimensional, and its uniaxial tensile experiment is simulated.The formation and propagation of concrete cracks as well as the failure mechanism ofconcrete material by meso-mechanics are studied in this paper.