The Experimental Study On The Split Strength Of SFRC

Steel Fiber Reinforce Concrete(SFRC) is made of hydraulic cements containing sand, aggregate and with randomly oriented steel fibers. Because the steel fibers reinforced the tension strength and toughness of the concrete, Steel Fiber Reinforce Concrete has been used as a construction material for tunnels, railway sleepers, nuclear reactor containment, airdrome, bridges, buildings and structures. During the using, the structures were unavoidable impacted by earth shake, blast and etc. Therefore, theoretically and practically, it is important to study the strength problem of steel fiber concrete. The main content of this paper includes:1. By the Brazilian disc split method, the spilt principle for the radial compression of rotating spheroid has been discussed. This method can realize C/T/T proportional loading by ordinary universal testing machine and the tested strength point with the Rode angelθ≡60 is on tension meridian line. The split principle and detailed operation method for concrete sphere specimen has been presented. The transform equation concerning Brazilian disc split strength, sphere specimen split strength, octahedral stress and the Rode angel has been obtained. The concrete specimen with 1% steel fiber has been tested.2. The influence of pulse shaper on the incident stress waver of split Hopkinson press bar has been calculated by FEM. The results show that the incident wave increases with the increase of thickness and reduction of diameter of the pulse shaper.3. The method to obtain the split strength of Brazilian disc by split Hopkinson press bar has been used to establish the testing method to gain the split strength of sphere specimen. The dynamic increase factors of Brazilian disc and sphere specimen has been obtained by the experiment on the concrete specimen with 1% steel fiber.4. The quasi-static three point bending fracture toughness test has been introduced to establish a series of fracture toughness testing methods by wedge split Hopkinson press bar on three point bending specimen. The plane strain fracture toughness under high and low strain rate has been obtained by the quasi-static and shock experiments on the concrete specimen with 1% steel fiber.5. The Ottosen theoretical model has been simplified by the property of the deviatonic stress plane envelope line of steel fiber concrete. The parabolic strength criterion model has been firstly presented for steel fiber concrete.6. Based on the experimental data, the linear computational model for dynamic increase factor has been presented, which is in simple form, easy to calculate and physically distinct and meets well with the experimental data.7. By the parabolic strength criterion model and the linear computational model of tension dynamic increase factor, the parabolic dynamic strength criterion model has firstly represented for steel fiber concrete. The results can provide some useful reference for the design, production, application and blast for steel fiber concrete.