Study On The Bond Behavior Of Interface Between Carbon Fiber Cloth And Steel Fiber Recycled Aggregate Concrete

With the continuous development and expansion of the city circle,the emergence of construction waste is always difficult to prevent,and the placement and reuse of a large amount of construction waste has become a problem to be solved.Recycled concrete is the solution to this problem.However,under the same water binder ratio,the mechanical properties of recycled concrete are worse than that of ordinary concrete,which limits the use of recycled concrete in structural components,so it is of great significance to optimize the mechanical properties of recycled concrete.The bearing capacity of ordinary concrete members can be improved by adding steel fiber or sticking carbon fiber cloth.Whether the above optimization measures can achieve the purpose of gain in recycled concrete remains to be further studied and analyzed.In this paper,recycled concrete and steel fiber are used as experimental variables to study the basic mechanical properties.On this basis,the interface bonding mechanism of carbon fiber cloth steel fiber recycled concrete is analyzed to provide theoretical basis for the research and design of carbon fiber cloth reinforced recycled concrete components.The main work of this paper is as follows:（1）The recycled coarse aggregate and steel fiber were used as test variables to carry out compression,splitting tensile test and bending toughness test of six groups of cube specimens.Among them,0%and 50%recycled coarse aggregate were used to replace,0.4%,0.6%,0.8%and 1.0%steel fiber were used to mix.The influence mechanism of recycled coarse aggregate and steel fiber on compression,splitting tensile and bending tensile strength of concrete was analyzed.（2）The interface bond performance test of carbon fiber cloth and steel fiber recycled concrete is completed,the interface failure form and stress process are analyzed,the ultimate bearing capacity is obtained,and the interface stress transfer law,effective bond length and slip evolution process are described.The influence mechanism of the replacement ratio of recycled coarse aggregate and the content of steel fiber on the interface bond is discussed.（3）According to the interface bond slip relationship,the simplified Lu XZ model and the popovics model and are used to fit the bond slip curve obtained from the interface bond performance test.The fitting results of the simplified land sign model are more in line with the actual situation.Based on the model,the expressions of characteristic parametersτ_m,s₀,G_fand tensile strength f_tare established.（4）Based on the test data,the influence of recycled coarse aggregate and steel fiber on the interface peel bearing capacity is discussed.By comparing the calculated value of the existing model with the test value,it is found that the formula of the interface debonding bearing capacity with the interface fracture energy G_fparameter can still accurately calculate the interface debonding bearing capacity of carbon fiber cloth recycled aggregate concrete under the action of steel fiber.The gain of steel fiber to the interface bearing capacity of carbon fiber cloth and recycled aggregate concrete is better than that of carbon fiber cloth and ordinary concrete.