| With the increasing of the total amount of building waste and the increasing pressure of natural environment in China,the 13th five-year Plan of China puts forward higher requirements for construction practitioners in terms of building energy efficiency and resource utilization.Because the performance index of recycled aggregate concrete is lower than that of ordinary concrete,its application scope has some limitations.Therefore,in order to broaden the scope of application of recycled concrete and reduce the influence of recycled aggregate on structure,recycled coarse aggregate is selected to replace some natural coarse aggregate to prepare standard recycled concrete.Steel-reinforced high-strength concrete composite structure has been widely used in engineering because of its high bearing capacity and good seismic performance,but its brittleness has hindered the development of this structure to a great extent.In order to improve the material properties,steel fiber reinforced high strength recycled concrete was prepared by adding steel fiber into reference high strength recycled concrete,and it was used in SRC structure.According to the existing research results,the primary factor affecting the working performance of steel fiber reinforced concrete is the amount of fiber.Therefore,the flexural properties of steel fiber-reinforced high-strength recycled concrete beams with different volume ratios of steel fibers were studied under two-point symmetrical concentrated load,and the group with the best working performance was selected,and the experimental results showed that the steel fiber-reinforced high-strength recycled concrete beams with different volume ratios of steel fibers had the best performance.The influence of reinforcement ratio and stirrups ratio on fiber reinforced steel reinforced concrete beams is analyzed.Nine groups of steel fiber reinforced steel high strength recycled concrete beams were made in this experiment.By changing the steel fiber blending ratio,reinforcement ratio and stirrups ratio,the failure form,deformation and bearing capacity of the steel fiber reinforced concrete beams were deeply analyzed.On thebasis of the existing codes,the formulas for calculating the flexural capacity of steel fiber-reinforced high strength recycled concrete beams are derived.At the same time,the finite element software ANSYS is used to simulate and analyze the test beam,and the finite element analysis results are compared with the test results.The results show that:(1)When the blending ratio of steel fiber is increased from 0.0%to 1.5%,the cracking load and ultimate load of the component show a tendency to decrease,and when the volume ratio of steel fiber is 1.0%,the bearing capacity and deformation performance of the component are the best.(2)When the reinforcement ratio increases from 0.7%to 1.9%,the crack load does not change much,the crack width decreases with the reinforcement ratio increasing,and the ultimate load increases significantly with the reinforcement ratio increasing.(3)When the stirrups ratio is increased from 0.21%to 0.38%,the cracking load and ultimate load of the members are not significantly different,but the increase of stirrups content can restrain the development of cracks and improve the ductility of members.The ratio of stirrups has a great effect on the deformation capacity of steel reinforced concrete beams at the later stage.(4)Combined with Steel-concrete Composite structure(SRC)and Steel Fiber reinforced concrete(SFRC),a formula for calculating the bearing capacity of steel fiber reinforced steel reinforced high strength recycled concrete beams is derived,and the rationality of the proposed formula is verified.(5)The finite element model of steel reinforced recycled concrete beam is numerically analyzed and calculated.The deviation between the simulated value and the experimental value of the test beam is within a reasonable range.It is shown that the simulation results of the ANSYS software are in good agreement with the measured values and meet the requirements. |
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