Study On Interfacial Bond-Slip Constitutive Relation Between Prestressed Carbon Fiber Slab And Concrete

In recent years,carbon fiber has been widely used in civil engineering because of its lightweight and high strength,corrosion resistance and other characteristics.Because of its high material utilization ratio and good durability,carbon fiber board reinforcement technology also has a good application prospect in the field of engineering strengthening.The bond behavior of the interface between carbon fiber board and concrete is the most important factor for strengthening concrete structure.So it is necessary to study the bond slip constitutive relationship between carbon fiber board and concrete interface.At present,most of the reinforcement works of carbon fiber materials are common paste methods,but there are many problems in common bonding methods.Hupup Compared with the bonded carbon fiber material,the prestressed carbon fiber technology can make full use of the advantages of the high strength of the carbon fiber board material,and it can also effectively delay the peeling damage of the carbon fiber material and effectively reduce the strain hysteresis effect.In this paper,a total of 12 groups of specimens were designed and fabricated,respectively,three groups of ordinary carbon fiber board reinforced specimens and nine groups of prestressed carbon fiber board strengthened specimens.The bond slip constitutive relationship between carbon fiber board and concrete is studied by means of experimental test and numerical simulation.The main research contents and conclusions are as follows:The influence factors on the mechanical properties of the interface between prestressed carbon fiber board and concrete are studied.Three factors affecting the width of prestressed carbon fiber board,the thickness of adhesive layer and the size of prestressing force were tested,and the combination of the main influencing factors was selected by orthogonal test design method.Nine groups of experimental beams were designed and fabricated to explore the bond-slip constitutive relationship between prestressed carbon fiber board and concrete.The orthogonal test results of nine groups of prestressed carbon fiber board reinforced concrete beams are analyzed.The results show that the order of influence on the peeling bearing capacity of the interface between prestressed carbon fiber board and concrete is the width of carbon fiber board from large to small.Initial tensile strength of carbon fiber board and adhesive thickness of adhesive layer;The optimum combination is that the thickness of adhesive layer is 2 mm,the width of carbon fiber board is 5 cm,and the initial tensile strength of carbon fiber board is 1200MPa.The bond slip constitutive relationship between prestressed carbon fiber board and concrete interface is studied.Using the local bond-slip curve obtained from the experiment,the data fitting curve was carried out on the basis of the typical constitutive relation model and compared with the fitting curve of the test result.The T-Ueda model was close to the corresponding constitutive model of the experiment.Based on the T-Ueda model,the constitutive relation of the experimental data is fitted.The constitutive relation includes three influencing factors of the initial tensile strength of carbon fiber board,namely the initial compressive strength of concrete,the compressive strength of concrete,and the thickness of adhesive layer.The model of the carbon fiber board and the concrete interface is established by using the finite element software of ANSYS,and the test strain value and the finite element calculation strain value at different positions of the test piece are compared,and the result is in good agreement with the test value.