Study On The Microstructure Of The Interface Of Rubber Concrete With Waste Tires And The Damage Law After High Temperature

Adding rubber particles(powder)into concrete can not only improve the performance of concrete,but also provide a way to deal with waste tires,which is an active response to the national environmental protection policy.Research on the application of waste tire rubber concrete on precast wallboard not only are development needs of prefabricated buildings,but also have significant meaning for the national energy conservation and emission reduction policy.In this paper,the mechanical properties,failure mechanism,pore distribution,thermal conductivity and mechanical properties after high temperature of waste tire rubber concrete are studied.The main results are follows:(1)The effects of rubber particle size and rubber replacement ratio on the mechanical properties of waste tire rubber concrete were studied by testing the cube compressive strength,axial compressive strength and splitting tensile strength of waste tire rubber concrete.The microstructure interface characteristics and failure mechanism of waste tire rubber concrete were observed by SEM electron microscope.The results show that the addition of rubber has a significant effect on the mechanical properties of concrete.Tensile strength and compressive strength are greatly reduced.(2)The pore structure of rubber concrete with rubber content and rubber particle size was studied by mercury injection test.The results show that the total porosity,median pore size,average pore size and specific pore volume of concrete increased with the addition of rubber particles,and the harmful porosity increased.(3)The thermal conductivity of waste tire rubber concrete with different water-cement ratio,different rubber particle size and different rubber content was measured by Hot Disk thermal constant analyzer.The model of thermal conductivity of rubber concrete with waste tire is fitted.The experiment shows that the thermal conductivity of concrete can be reduced effectively by adding rubber,and the bigger the ratio of water to cement is,the smaller the coefficient of thermal conductivity is.The difference of thermal conductivity between rubber concrete with different rubber particle size is very small.(4)Based on the tests of mass loss,cube compressive strength and splitting tensile strength of waste tire rubber concrete with different temperature and different rubber content,the damage law of waste tire rubber concrete at high temperature is analyzed.The damage models of cubic compressive strength,splitting tensile strengthand rubber content of waste tire rubber concrete are fitted.The test results show that the strength of rubber concrete decreases with the increase of temperature and the increase of rubber content.And the greater the rubber content,the faster the speed of reduction.