Experimental Study On The Interface Mechanical Properties Of Bamboo-geopolymer Concrete Composite Structure

The bamboo-geopolymer concrete composite structure is a new type of composite structure,which uses the engineering bamboo with higher tensile strength as the tensile zone,the fly ash geopolymer concrete with better compressive strength as the compression zone,and a shear connector at the interface between the two materials.In terms of material utilization,engineering bamboo and fly ash geopolymer concrete have the characteristics of resource regeneration,energy saving,and environmental protection.In terms of structural form and stress characteristics,the bamboogeopolymer concrete composite structure is similar to the bamboo-concrete composite structure,which can give full play to the tensile and compressive characteristics of the bamboo and concrete materials,and it can replace part of reinforced concrete to meet the demands of engineering field.Focusing on the research topic of the interface mechanical properties of the bamboo-geopolymer concrete composite structure,this thesis conducted the experimental research on the basic mechanical properties of the fly ash geopolymer concrete,interface-slip performance test of the bamboo-geopolymer concrete structure,and finite element analysis of bamboo-geopolymer concrete composite beam.The main research work of this thesis is as follows.Firstly,the basic mechanical properties of fly ash geopolymer concrete under uniaxial compression were studied experimentally.The tests include the mix proportion design of fly ash geopolymer concrete,compressive strength and elastic modulus tests,then stress-strain relationship and Poisson's ratio tests,and a study on the effects of different cement contents on the mechanical properties of fly ash geopolymer concrete.The research results show that the addition of cement and early temperature curing can accelerate the early strength improvement of fly ash geopolymer concrete,and the two methods have no obvious difference.The ultimate lateral expansion tensile strain of fly ash geopolymer concrete is much larger than that of ordinary concrete,and the Poisson's ratio of fly ash geopolymer concrete is obviously different from that of ordinary cement concrete.The Sazen model is used to describe the stress-strain relationship curve of the fly ash geopolymer concrete in this thesis,and the curve shape is modified according to the test results.Secondly,in this thesis,the interface-slip properties of the bamboo-geopolymer concrete composite structure were studied,and it is also known as load-slip test.In this experiment,a total of 12 specimens in 4 groups were designed and manufactured,the bearing capacity and failure form of the groove-bolt composite shear connector were studied.The results show that the failure of composite structure starts from the failure of concrete in the groove of shear joint,and the groove is the key factor affecting the shear performance of composite structure.It can be seen from the load-slip curve diagram that the single-groove composite structure is dominated by brittle failure,and the loading process is basically in the linear phase,while the double-groove composite structure has an obvious ductile failure.Finally,the finite element analysis of the bamboo-geopolymer concrete composite beam was carried out,the effects of different interface connections and different concrete materials on the overall mechanical properties of the composite beam were compared.It lays a theoretical foundation for future experiments.