Experimental Study On Bond-slip Behavior Between Steel Shape And Concrete In Steel Reinforced Recycled Concrete Structure

As a kind of green energy-saving building materials,recycled concrete not only solves the problem of shortage of resources,but also alleviates the environmental problems that caused by the accumulation of urban garbage.However,recycled concrete has many disadvantages,such as large water cement ratio,apparent density,porosity,low tensile strength,low elastic modulus,large creep deformation and poor seismic performance.Steel reinforced concrete members are widely used because of the advantages of large bearing capacity,high stiffness,good ductility,good hysteretic behavior and good seismic energy dissipation.In this paper,according to the characteristics of the two types of materials,the steel can be used in recycled concrete members to form the recycled concrete structure and the bond slip behavior between them has been researched.The cohesive action between steel and recycled concrete is the basis of work and direct effect on the mechanical behavior,failure mode,ultimate bearing capacity,stiffness,crack,and the deformation calculation theory.In the previous research based on the basic mechanical properties of recycled concrete,thirty-six pieces of standard push out specimens has been designed to study on the bond slip properties of steel reinforced concrete structure regeneration,considering influence of the factors of recycled coarse aggregate replacement rate,the tensile strength of recycled concrete,steel protective layer thick Ness,steel embedment length,stirrup ratio and so on.The following conclusions had been obtained through experimental study:(1)Builting the electronic slip sensor,the relative slip between steel and recycled concrete had been measured directly,and the strain of steel flange and web had been measured by the combination of steel;(2)Through analysis of the influence of the bond slip performance of concrete factors of steel recycled,the calculation formula of bond strength between steel and concrete regeneration had been established;(3)Based on the experimental results,the average bond strength of the recycled concrete structure and the slip distribution of the loading had been established;(4)Based on the experimental results,two position functions which can be used to determine the relationship between the bond slip and the anchorage length had been obtained;(5)Through the study of the stress state of the connection between steel and recycled concrete,bond failure criterion of steel reinforced recycled concrete structure had been established,based on failure mechanism and bond strength of recycled concrete.In this paper,the bond slip constitutive model of steel recycled concrete had been established,which builting the foundation for the finite element analysis and long-term deformation behavior of recycled concrete.