Study On Bending Behavior Of Reinforced Steel Fiber Recycled Concrete Beams

With the rapid development of the economy,the scale of the city continues to expand.More and more old buildings have been demolished,and the amount of waste concrete produced has also increased day by day,adversely affecting society and the environment.In order to utilize waste concrete and reduce waste of resources,recycled concrete came into being.A large number of experimental data show that the mechanical properties of recycled concrete are lower than ordinary concrete,which limits the application of recycled concrete in engineering.Adding the right amount of steel fiber to the concrete can enhance the performance of the concrete.In order to give full play to the advantages of recycled concrete and steel fiber,the two are combined to produce a new type of steel fiber mixed recycled concrete.For the time being,research on reinforced steel fiber mixed recycled concrete beams is not extensive and in-depth.Then four sets of reinforced steel fiber mixed recycled concrete beams were designed to study the mechanical properties and deformation characteristics of steel fiber reinforced mixed concrete beams under bending.By recording the experimental data and analyzing the test data,the calculation formula for the steel fiber recycled concrete beam is proposed.Based on the experimental phenomena and experimental data,the following main conclusions are obtained after analysis:(1)Reinforced steel fiber mixed recycled concrete beams can meet the flat section assumption under the condition of bending.From the beginning of loading to the failure,the failure morphology and deformation characteristics are basically consistent with ordinary concrete beams.(2)The current calculation method for the flexural capacity of normal section in the Technical Specification for Fiber Reinforced Concrete Structure(CECS38-2004)is applicable to steel fiber mixed recycled concrete beams.(3)The maximum crack width of the steel fiber mixed recycled concrete beam is Wfmax=λWmax(1-βcwλf),Wmax is calculated according to the "Concrete Structure Design Code”(GB50010-2010),and βcw and λf are valued according to the Technical Specification for Fiber Concrete Structure(CECS38-2004).λis a coefficient related to the strength of steel fiber mixed recycled concrete:λ=0.013*ffc+0.382.(4)The stiffness of the steel fiber-fiber hybrid recycled concrete beam is approximately 0.81 times the calculated value calculated according to the Technical Specification for Fiber Concrete Structure(CECS38-2004).