Research On The Properties Of Rubberized Concrete Containing Surface-modified Rubber Powders

Mixing rubber powder made from waste tires into concrete can not only improve the performance of concrete(toughness,impact resistance,impervious,freeze resistance,etc.),but also effectively realize the resource utilization of waste tires,which is of great research significance.Previously,the majority of researchers have carried out in-depth research on the performance of rubber concrete,found that though the addition of rubber powder improved the performance of the concrete,but also reduced its strength,which seriously hindered the development and application of rubber concrete.In order to improve the strength of rubber concrete,this paper analyzed the reasons of the strength decrease,used three surface modification methods(NaOH soaking,sulfonation and amination)to pretreat the rubber powder,and through water contact angle test,FT-IR characterization and scanning electron microscopic revealed the modification principle from the microscopic,compared the effect of each modification method,and tested the mixture performance,basic mechanical properties(the compressive strength,flexural strength,splitting tensile strength,impact resistance,modulus of elasticity)of rubber concrete before and after modification.The influence of surface modification of rubber powder on the properties of rubber concrete is analyzed,finally,ANSYS software was used to simulate the experiment.Through the experimental analysis and research,the following main conclusions are obtained:(1)the hydrophobic property of rubber powder surface and the low elastic modulus of rubber powder are the main reasons for the reduction of the rubber concrete strength.The influence of the elastic modulus can be weakened by reasonable mix design,while the hydrophobic property of rubber powder surface needs to be solved by surface modification.(2)NaOH immersion,sulfonation and amination modification all improved the hydrophobicity of rubber powder surface,but NaOH immersion only dissolved impurities insoluble in water on the surface of rubber powder,and the surface of rubber powder was still hydrophobic.Sulfonation and amination introduced a large number of hydrophilic groups on the surface of the rubber powder,and the surface of the rubber powder completely changed to hydrophilic.(3)the working performance of the newly mixed rubber concrete after modification is improved to a certain extent compared with that of the unmodified rubber concrete,but the gas content will be reduced to a certain extent,but it is still higher than that of ordinary concrete.(4)NaOH modification has little effect on the compressive strength of rubber concrete,but it can greatly improve the flexural strength and splitting tensile strength of rubber concrete,and the.impact resistance is 1.8 times as high as that of ordinary concrete.(5)the strength of amine-modified rubber concrete reaches 96-98%of that of ordinary concrete,and the impact resistance of sulfonated rubber concrete is twice as high as that of ordinary concrete.Both modified rubber concrete by the two modification methods have broad development prospects.(6)the calculated value obtained by ANSYS simulation test after modeling approximates the measured value of the test,indicating that the modeling is accurate and reasonable,and it can be used for simulation analysis of rubber concrete in future studies.