Study On Impact Energy Dissipation Of Rubber Concrete With Large Amount Of Rubber

Due to the low reuse rate of waste tires,incineration and landfilling will not only cause waste of resources,but also increase environmental pollution.In addition,with the rapid development of infrastructure,a large number of river sand mining has caused irreparable damage to the natural environment.The replacement of aggregate in concrete with rubber particles can not only solve part of the environmental pollution problem and reduce excessive dependence on natural resources,but also improve the mechanical properties of concrete.In order to ensure the feasibility of the test study,rubber particles with particle sizes of 20-40 were used in the test to replace fine aggregate in concrete with volumes of(0%,20%,40%and 60%).Meanwhile,the additive silica fume was used to replace cementing material cement in concrete with qualities of(0%,5%and 10%)to improve the strength of rubber concrete.This paper mainly includes three parts:testing and analyzing the static basic mechanical properties of rubber concrete,testing and analyzing the impact resistance of rubber concrete under low speed,testing and analyzing the dynamic mechanical response of rubber concrete under high speed impact.(1)The apparent density,compressive strength and splitting tensile strength of concrete at different ages were tested under four different rubber and three silica ash contents.The characteristics of static test after failure were observed and analyzed,and the influence of rubber content on concrete toughness was qualitatively analyzed.Finally,the tensile ratio of 28 days is analyzed to quantitatively judge the toughness of rubber concrete.(2)Three different drop hammer impact devices were manufactured to test the impact resistance of rubber concrete with large dosage at low speed.Firstly,according to the test device for the impact resistance of concrete circular cake made by ACI544 Committee,the energy consumed by the first crack and the energy consumed by the final failure on the upper surface of concrete specimens were tested with the increase of the mixture of rubber and silica fume.Secondly,according to the device modified by Professor Deng Zongcai of Beijing University of Technology to test the flexural impact energy of concrete beams,the energy consumed by the first crack at the bottom of concrete beams and the energy consumed by the final failure were tested with the increase of the mixture of rubber and silica ash.The third is the self-made cube test block rebound absorption energy test device.Through testing and calculating the falling gravitational potential energy of steel ball minus the rebound potential energy,the resilience absorption ability of rubber concrete can be judged qualitative.(3)The third part adopts the hopkinson pressure bar impact device with variable cross section and adopts four kinds of air pressure(0.4MPa,0.5MPa,0.6MPa,0.7MPa)to carry out impact tests on concrete with different rubber and silica ash content.The test results contents include:dynamic stress-strain curve,dynamic peak strength,peak strain corresponding to peak strength,relationship between strain rate and dynamic compressive strength,and relationship between impact pressure and dissipative energy density.Finally,the final failure state of concrete with various rubber and silica fume contents after the impact of different air pressure is analyzed.Test based on the large quantity of rubber concrete has carried on the basic mechanical properties test,impact test at low speed and high speed impact test,for large quantity of rubber concrete can be used in the anti-collision pier,coastal concrete protective structure,the pedestrian path and for large deformation demand provides the theory basis for building structures,etc.Figure[22]table[8]reference[78]...