Experimental Study On Adhesion Performance Of Steel Fiber Modified Rubber Concrete And Deformed Steel Bar

Rubber concrete is a green building material composed of rubber particles ground from waste rubber.It has the advantages of low elastic modulus,good crack resistance and energy dissipation,and has a wide application prospect.However,the incorporation of rubber has reduced the strength of concrete,which greatly limits the promotion and application of rubber concrete.In order to make up for the strength defects of rubber concrete,this paper discusses the enhancement effect of steel fiber on its mechanical properties,and studies the influence of steel fiber volume ratio,anchorage length,steel bar diameter and protective layer thickness on the bonding performance of rubber concrete and deformed steel bar.The main contents are as follows :(1)Seven groups of specimens were designed by different rubber content and steel fiber volume ratio,and the cube compressive and splitting tensile tests were carried out respectively.The effects of rubber content and steel fiber volume fraction on the failure mode,cubic compressive strength and splitting tensile strength of the specimens were observed.The influence coefficient of rubber powder content on strength and the influence coefficient of steel fiber volume ratio on strength were fitted by statistical regression of test data.The formula of rubber powder content on the strength of C30 ordinary concrete and the formula of steel fiber volume ratio on the strength of rubber concrete are given.Determine the rubber powder content and steel fiber volume ratio of the steel fiber modified rubber concrete bonding specimen.(2)Through the pull-out test of 12 groups of bonding specimens,the influence of steel fiber volume ratio,steel bar diameter,protective layer thickness and anchorage length on bonding specimens was studied for 5 % rubber concrete.The failure mode of bonding specimens was observed,and the influence of the above factors on bond strength and bond slip curve was analyzed.The ultimate bond strength prediction formula of steel fiber modified rubber concrete was established.(3)According to the bond curve of steel fiber rubber concrete,the bond slip constitutive model is selected.According to the experimental data,the rising coefficient is fitted,and the relationship between the coefficient and the volume ratio of steel fiber is established.The average bond slip constitutive model of steel fiber modified rubber concrete and deformed steel bar is proposed.