Study On Mechanical Properties And Application Of Layered Steel Fiber Rubber Concrete

The toughness,fracture resistance and deformation ability of the concrete can be improved by adding rubber powder to the concrete.However,the addition of the rubber powder will cause the concrete to be significantly reduced in strength,which limits the application of rubber concrete.The steel fiber is incorporated into the rubber concrete to form the new material composed of rubber concrete and steel fiber layers,which can effectively and economically enhance the reinforcing effect of the steel fiber on the concrete and overcome the decline of mechanical properties of concrete caused by the addition of rubber powder.Therefore,the concrete blended with steel fiber and rubber can be further developed and applied.Based on ordinary C50 concrete,adding three different sizes of rubber(No.20,No.40,No.60)with 5% cement quality and five different volume fractions of steel fiber(0.5%,1.0%,1.5%,2.0% and 2.5%),layer steel fiber rubber concrete is prepared.The main research contents are as follows:(1)Through cubic compressive test,splitting tensile test and four-point bending flexural test,the effects of volume ratio of steel fiber and particle size of rubber powder on compressive strength,tensile strength and flexural strength of steel fiber reinforced rubber concrete are compared and analyzed,and the failure process and failure mode of the specimens are observed.(2)By analyzing the freeze-thaw morphology,relative dynamic elastic modulus and mass loss rate of concrete after freeze-thaw test,it can be found that the size of rubber powder has a greater impact on the freeze resistance of concrete.The optimum degree of the size of rubber powder on the freeze resistance of LSFRRC is No.40 > No.60 > No.20 in turn.That is to say,LSFRRC with No.40 rubber powder has the best freeze resistance,followed by No.60 rubber powder,and No.20 rubber powder had the worst antifreeze effect.(3)According to the definition of damage variable of the concrete,the freeze-thaw damage model of layer steel fiber reinforced rubber concrete under freeze-thaw cycle is established,and its mathematical model of freeze-thaw damage is accurately regressed according to freeze-thaw test data.Finally,according to the freeze-thaw damage model,the freeze-thaw life of concrete is predicted.