Mesomechanical Model And Failure Analysis Of Concrete Material

In this paper, concrete is taken as three-phase composites consisting of mortar matrix, aggregate and the bond between matrix and aggregate. Based on the random distribution of aggregate in concrete, the optimal gradation formula is adopted, and the throwing program of aggregates for two- and three- dimensional concrete sample is made. By batch commands scheme and gradually mesh generation method, the aggregate elements , the interface elements and the matrix elements are generated. Especially for three-dimension meso-finite element model, the gradually mesh generation method has high fasten calculate ability than mapped mesh method because of less freedom degrees.Taking the aggregate, matrix and the interface as isotropic materials, and the mechanics parameters of aggregate, matrix and concrete are measured by experiments. With series of discrete value on interface parameter, the relationship curve diagram of elasticity modulus of interface and concrete is deduced by calculation, and the appropriate interface elasticity modulus is obtained with interpolation method.Based on the random aggregate distribution meso-finite element model, all kinds of typical numerical experiments such as uniaxial tensile test, uniaxial compress test, triaxial compress test, split test and the beam bending test have been made and their failure process are simulated. The strength parameters such as the tensile strength, the compress strength, the split tensile strength and the bending strength are gained subsequently deduced by the limit carrying capacity and the geometry size of concrete sample.The meso-finite element models with different shape aggregate such as circle, ellipse, prism and combined type have been established, and the correspond failure process and the limit carrying capacity are analyzed.The result fie is dealt with only for these element which belong to the biggest plasticity section domain by area(volume for three-dimension) weight method. And the elasticity modulus, the uniaxial tensile stress-strain relationship, the uniaxial compress stress-strain relationship, the triaxial compress principle stress-strain relationship are gained. By these stress-strain relationships, the micro mechanism of macro mechanicsproperties of concrete can be mastered better.