Study On The Meso Mechanism Of Rubber Concrete Strength

Strength is an important index of concrete structure design and safety evaluation.Because of the introduction of rubber material,the strength of rubber concrete is lower than that of ordinary concrete.It has seriously affected its application in practical engineering.In order to improve the performance of the rubber concrete,it is necessary to study the internal mechanism of the formation of the strength of the rubber concrete.In this paper,a numerical model for calculating the strength of rubber concrete is established by means of micromechanics,the cracking process of rubber concrete was simulated and the mechanism of strength formation was analyzed.The main contents and conclusions are as follows::(1)The constitutive relation and mechanical properties of the main components of the rubber concrete were analyzed.On the basis of investigating the current situation of rubber material and concrete interface transition zone,the related research results about the constitutive relation and mechanical properties,microstructure and mechanical properties of the interfacial transition zone of the concrete were sorted out.The results provide a basis for the determination of the constitutive relation of the material and the selection of the meso parameters.(2)A mesoscopic numerical model of rubber concrete is established.At the meso level,the rubber concrete is considered as a composite material consisting of mortar matrix,aggregate,rubber particles,coarse aggregate mortar interface,rubber particle mortar interface and initial defects.A mesoscopic numerical model is developed which is closer to the real structure of rubber concrete.The applicability of the model is verified by comparing the results of the tests with those of rubber concrete under uniaxial compression and splitting tensile tests.(3)The cracking process of rubber concrete is simulated,the effect of each micro component on the macroscopic strength was analyzed.The influence of the strength of mortar,the initial defects in the two kinds of interface,the content of rubber and the particle size on the uniaxial strength of concrete was analyzed;Among them,the influence of mortar strength and rubber content on the strength of rubber concrete,secondly,the initial defect content of interface;The rubber particle size and the initial defect content in the rubber particle mortar interface have little influence on the strength of the rubber concrete.(4)Comprehensive micro simulation and macroscopic test results,the strength and failure mechanism of rubberized concrete are studied in this paper.Compared with ordinary concrete,rubber concrete has a rubber mortar interface,as a result,the interface is more complex.With the addition of rubber,more pores,microcracks and other initial defects are brought into rubberized concrete,and the initial defect content increases with the increase of rubber content.By means of meso numerical simulation,the results show that the strength of rubberized concrete decreases continuously with the increase of initial defect content and element area.