Experimental Study On Forst Resistance And Damping Capacity Of Modified Rubber Concrete

When rubber particles are used in concrete,the utilization ratio of the waste rubber is improved,which is conducive to environmental protection and social sustainable development.The rubber particles were modified by NaOH solution.The effects of NaOH solution concentration,rubber particle size and content on the mechanical properties and frost resistance of concrete were studied.Free vibration tests of concrete cantilever beams with rubber particles modified by NaOH solution were carried out to study the influence of rubber content and damage degree on damping ratio.The test results show that:(1)The strength of concrete decreases with the increase of rubber content.The strength of the rubber particle size of 1～2mm concrete are larger than that of the 2～4mm.Modification of rubber particles with NaOH solution with a concentration of 5%and 10%can improve the strength of rubberized concrete.The modified effect of NaOH solution with a concentration of 5%is better than that of NaOH solution with a concentration of 10%.When the rubber content is 20%,the strength is increased by about 12%.(2)When the rubber content is less than 20%,the frost resistance of concrete increases with the increase of rubber content.The mechanism of frost resistance enhancement of rubber concrete is clarified through "freezing and thawing model".Compressive strength formulas related to rubber content and freeze-thaw cycles were established and compared with experimental data in the test and related literature.The calculated values were close to the experimental values.(3)The damping ratio of the rubber concrete cantilever beam increases with the increase of the rubber content and the damage degree.Compared with the base concrete cantilever beam,the damping ratio increases about 60%when the rubber content is 20%,and the damping ratio increases by about 160%when the damage coefficient is 0.8.(4)The mathematical model of damping ratio and bending dynamic stiffness loss degree of rubber concrete cantilever beam and the mathematical model between damping ratio and stress level of bending control section of cantilever beam are established.The calculated values are in good agreement with experimental data in the test and related literature,and the damping ratio can be estimated according to the static load effect of reinforced concrete cantilever beam.