Study On Mechanical And Thermal Properties Of Shale Ceramsite Concrete Based On Micromechanical Method

Lightweight aggregate concrete is a kind of concrete which is made of lightweight aggregate instead of ordinary aggregate,which ensures the basic strength of the material at the same time greatly reduces the weight of the structure.The use of lightweight aggregate instead of ordinary aggregate for a lot of concrete performance had a greater impact.In order to understand the thermal and mechanical properties of lightweight aggregate concrete,many scholars have carried out research on lightweight aggregate concrete.At present,the research on lightweight aggregate concrete mainly focuses on the improvement of the performance of the concrete on the macro level,such as adding various kinds of admixtures,fibers,etc.There are also studies on the effect of high temperature on the performance of lightweight aggregate concrete,but there is little research on the relationship between light aggregate and concrete.In order to understand the influence of lightweight aggregate on concrete performance and the relationship between the materials and concrete,the theoretical formulas of the parameters of lightweight aggregate concrete,cement mortar matrix and lightweight aggregate are established by means of the theory of micromechanics homogenization.At the same time,designing multi-level material test,determinating the performance parameters of concrete uniform and mortar matrix,carry out thermal coupling test,the experimental results are included in the theoretical formula to verify the accuracy and applicability of the theoretical model.In addition,based on the theory and experiment,establishing the random aggregate model and predicting the parameters of concrete by the finite element software,which makes the theory?experiment and simulation combine with each other.Under this premise,this article mainly carries on the following work:(1)Pruduct the concrete specimens with shale ceramsite aggregate in the ratios of 0%(cement mortar),20%,30%,40% in volume,to study the influence on the performance of concrete with different ratio of volume,and be a basis for inversion derivation of lightweight aggregate thermodynamic parameters.(2)Test compressive strength,elastic modulus and thermal expansion coefficient of the various lightweight aggregate concrete specimens,the result show that the lower the aggregate density,the smaller the elastic modulus? compressive strength and thermal expansion coefficient of lightweight aggregate concrete.In addition,the larger the volume ratio of lightweight aggregate,the smaller the performance parameters.(3)Deduce the relationship between the thermodynamic parameters of concrete and its components with the aid of micromechanics homogenization theory.Then,the elastic modulus and thermal expansion coefficient of lightweight aggregate are obtained by substituting the measured data.(4)Software simulation is used to get the performance parameters of concrete on the basis of the theoretical calculation and the experimental data,and compare with the theoretical results and the test conclusion.To make theory,test and simulation verify each other.