Study On Bonding Performance Of Rc Beam Strengthened With NSM Aluminum Alloy Bars

Compared with external reinforcement technology,The near surface mounted(NSM)is more and more popular with researchers.That is,structural glue is used to fill the reinforcement into slotted concrete,to improve the debonding capacity of the members.The aluminum alloy(AA)embedded reinforcement technology combines the superior AA reinforcement with the embedded reinforcement technology,and gives full play to the mechanical properties of the reinforced reinforcement.However,there are still some problems in the practical reinforcement engineering,among which the outstanding problems are the bonding properties of AA-adhesive joint and adhesive-concrete joint.The bonding behavior and deboding capacity of AA-adhesive and adhesive-concrete are the importent problems in the field of embedded reinforcement technology,which play a decisive role in the bending of the structure.The bond-slip relationship is very important for the study of macroscopic mechanical properties of AA and structure.Therefore,based on the experimental study of AA embedded reinforced concrete beam,an analytical model is established to analyze the bonding behavior of structural glue-concrete interface.The bond-slip constitutive model of AA reinforced beam and the calculation model of interfacial peeling debonding capacity are derived.The main research work of this paper are:This paper uses the method of test and finite element model(FEM)on the interface,analyzes the fracture process,stress distribution of AA and the interface bond-sliding curve.The research results show that the interface debonding of the reinforcement beam starts near the loading end and develops to the reinforcement end.As the load increases,the reinforcement stress reaches the maximum near the loading end and the closer to the reinforcement end;The bond-slip curve shows the reinforcement beam from the beginning until the interface debonding,guiding for further theoretical research and FE analysis.Based on the FEM,the influence of concrete strength,number of AA bars and reinforcement steel bond length on the interface bond performance of reinforced beams is analyzed.The research results show that the concrete strength,the number of AA bars and the bond length of AA bars will have a great impact on the bond strength of aluminum alloy reinforcement beams.The bond strength of AA-adhesive joint and adhesive-concrete joint will increase by the concrete strength and the number of AA bars,and will gradually decrease due to the bond length of AA bars.Through numerical regression analysis,The expressions of main mechanical performance index and bond-sliding relation of multi-parameter interface are obtained.By simulated and analyzed the collected test beams,the results agree with the collected test results,providing an important theoretical basis for the calculation model of the interface debonding capacity.Based on the research results of FE analysis,the calculation model of the embedded reinforced beam is derived.In comparison with the collected debonding capacity calculation model,the proposed calculation model has better calculation effect and verified collected test data.The calculation model is derived by numerical analysis,which provides an important reference for the design and analysis of AA embedded reinforcement specimens.