Study On The Interfacial Transition Zone Feature And Improving Mechanical Properties Of Rubber Concrete With Waste Tires

With the rapid development of the automobile industry,the number of used tires has also increased year by year,causing serious black pollution: polluting soil,water sources and even endangering human health.Therefore,solving the environmental pollution problems of waste tires and exploring effective ways to recycle them have gradually attracted the attention of the govermennt and society.In this paper,the structural characteristics of the interface transition zone,compressive strength,ultrasonic sound velocity and pore structure of the waste tire rubber concrete are experimentally studied.The main research results are:(1)The strength of waste tire rubber concrete is lower than that of ordinary concrete with the same mixing ratio.When the amount of rubber is the same,the strength of waste tire rubber concrete decreases with the decrease of the rubber particle size;When the particles of rubber is the same,the strength decreases with rubber content increases;the regression equation of the ultrasonic sound velocity and compressive strength of the waste tire rubber concrete is fitted.Under the same mix ratio,the change law of the ultrasonic sound velocity value of the waste tire rubber concrete is consistent with its strength;The silane modifier has a certain degree of improvement in the strength of the rubber concrete.The improvement effect of the modified rubber concrete strength is not that the larger the particle size,the better the improvement effect.The 1-3mm rubber particles have the best improvement effect.(2)Through micro-testing of waste tire rubber concrete,SEM and EDS were used to analyze the micro-structural characteristics of the interface transition zone;The effects of the modifier,rubber content and particle size on the micro morphology,hydration products,elements distribution,interface width and other effects of the interface transition zone were studied,the results show that:(1)There are cracks between the aggregate of ordinary concrete and rubber concrete or rubber and cement matrix;(2)The C-S-H content of the interface area of rubber concrete is less than that of ordinary concrete,in the case of larger rubber content,the hydration products in the interface transition zone are mainly CH;in addition,the C-S-H content of the rubber particle concrete interface zone is more than that of the rubber powder concrete;(3)The incorporation of rubber powder and particles changed Ca,Si,Al,Fe,Na and other elements distribution law and content;(4)Width of rubber powder concrete interface area>Width of rubber concrete interface area with rubber particle size of3-6mm> Width of rubber concrete interface area with particle size of 1-3mm> Width of reference concrete interface area;(5)The incorporation of modifier reduces the concentration of CH crystals and promotes the formation of C-S-H,which has a certain width on the interface area of waste tire rubber particle concrete.The effect of the reduction has a great influence on the redistribution of Ca element,but has little effect on the redistribution of Si element.(3)The internal porosity,pore size distribution and other parameters of waste tire rubber concrete were measured by mercury intrusion method.The influence of different water-cement ratio,particle size and modified rubber particles on the pore structure of waste tire rubber concrete was studied and analyzed the effect of the difference in pore structure on the mechanical properties of waste tire rubber concrete.The research results show that:(1)The smaller the water-cement ratio,the smaller the specific pore volume,total porosity,"harmful" porosity,and average pore diameter of the waste tire rubber concrete;(2)When the rubber is powder,the smaller the particle size,the larger the specific pore volume,total porosity,"harmful" porosity,and average pore diameter of the waste tire rubber concrete.When the rubber is granular,the larger the particle size,the specific pore volume,the total porosity,the "harmful" porosity,and the average pore diameter the larger;(3)The modifier improves the pore structure of the waste tire rubber concrete,which can significantly reduce the porosity and pore size of the rubber concrete.The paper has pictures 85;Tables 31;Referenrences 105...