Study On Mechanical Properties Of Discarded Hub Fiber Concrete

In recent years,with the rapid development of the automobile manufacturing industry,more and more discarded tires have been produced,which makes the problems of resource and environment have gradually become the focus of social attention.At the same time,the cost of concrete is high,the reinforcement effect of new steel fiber is good,but the cost is high.Therefore,it will bring huge economic and social benefits if the discarded automobile tire can be processed into discarded hub fiber instead of steel fiber to play the role of strengthening and toughening in concrete.On the basis of the existing relevant specifications for the selection of steel fiber concrete test variables,this paper takes the volume ratio of discarded hub finer(0,0.5%,1.0%,1.5%,2.0%)and the length-diameter ratio(40,60,80,100)as variables to research on the workability of mixture and strength of concrete.Through the axial compression test and beam bending test,the constitutive relation and bending characteristics of the discarded hub fiber concrete are studied.Finally,the finite element simulation analysis is performed using ABAQUS CAE.The main content of this paper includes the following aspects:1)The basic physical properties of raw materials are tested to obtain the length,diameter,density and ultimate tensile strength of the discarded hub fiber,and the silt content,crushing value and other indicators of fine aggregate and coarse aggregate;2)Through the experimental study on the slump of 17 groups of mixtures with different mix ratios,the variation law of the workability of the mixture of discarded hub fiber concrete with fiber volume rate and fiber length-diameter ratio is discussed.3)The compression strength,splitting strength and flexural strength test of 17 groups of cube specimens(150mm*150mm*150mm),17 groups of cylinder specimen(Φ150mm*300 mm)and 17 groups of prism specimens(550mm*150mm*150mm)after standard maintenance of 28 days is performed respectively.Through the experimental results and the experimental failure modes,the variation of the compression strength,splitting strength and flexural strength of discarded hub fiber concrete with the volume ratio and length-diameter ratio of fiber is studied,and the mechanism of the discarded hub fiber in concrete is analyzed;4)The uniaxial compression test of cylinder specimen is conducted by using the WWWS-1000 B microcomputer controlled electro-hydraulic servo universal materialtesting machine to analyze the stress-strain relationship of discarded hub fiber concrete under different fiber volume ratio;The stress-strain scatter diagram of the specimen with the fiber volume ratio of 1.0% and length-diameter ratio of 80(note: this is the optimal fiber volume ratio and length-diameter ratio obtained from the above test conclusion)is fitted and modified,and the constitutive equation of the discarded hub fiber concrete is derived.According to the stress-strain diagram,the elastic modulus of concrete under each volume ratio is calculated,and the influence of fiber volume ratio on the elastic modulus of concrete is analyzed.5)According to the optimal fiber volume ratio and the optimal fiber length-diameter ratio,the beam of discarded hub fiber concrete is prepared,and the bending test is carried out to analyze the variation law of load(force)and deflection(displacement)during the bending process,which is compared with the plain concrete.On the basis of the test,the beam bending performance of discarded hub fiber concrete is analyzed nonlinearly by using ABAQUS,a large general finite element software,and the stress distribution in the bending process of discarded hub fiber concrete is studied by comparing the numerical analysis results with the test results.