Fiber-reinforced UHPC-concrete Composite Column Material And Force Performance Rresearch

UHPC-concrete composite columns can also be assembled in structure,which can be quickly and efficiently applied to engineering practice.In this paper,the bulk density theory of the UHPC material foundation is used as an entry point to conduct an in-depth study of the UHPC mix ratio,and use a large number of tests to verify its performance to obtain the best mix ratio,laying the foundation for the next step of research.Design the structural dimensions of UHPC-concrete composite columns.Finite element software was used to analyze the relationship between ultimate bearing capacity and load-strain.The basic performance of the combined column is obtained.The main research contents are as follows:Chapter 1: Introduce the current research status of ultra-high performance concrete(UHPC)and concrete-filled steel tube at home and abroad,elaborate on its research focus,and then put forward a new structural form of UHPC-concrete composite column,focusing on its characteristics.Chapter 2: Introduce the test method and equipment requirements of ultra-high performance concrete materials test,based on the maximum packing density theory Dinger-Funk equation,using the difference between the gradation of machine-made sand and river sand particles,design two kinds of admixture The proportioning method,through experimental analysis,determines the proportion coefficient in the mixed sand,which lays a solid foundation for the preparation of ultra-high performance concrete.Chapter 3: Material test: The material ratio,water-binder ratio,sand-rubber ratio and steel fiber volume fraction which have the greatest impact on the performance of ultra-high-performance concrete are used as the analysis variables.Several major influencing factors are determined step by step through the control variable method.Comprehensive analysis of pressure and splitting test data and SEM micro-analysis and slump and fluidity performance data determine the optimal ratio.And test and analyze the failure form,axial compressive strength and elastic modulus of ultra-high performance concrete with different steel fiber content.Chapter 4: Design UHPC-concrete composite columns with different wall thicknesses,different core concrete strengths,and different stirrup spacing to determine the constitutive relationship of UHPC,ordinary concrete,and steel.The selection of finite element calculation method to establish the model.Chapter 5: Finite element analysis of 8 size models through ABAQUS finite element software,mainly on its equivalent cloud diagram,ultimate bearing capacity,load-axial strain relationship,load-transverse strain relationship,load-stirrup strain relationship Comparative analysis.The effects of wall thickness,core concrete strength and stirrup spacing on the mechanical properties of UHPC-concrete composite columns are comprehensively described.