Research On Mechanical Properties Of Molybdenum Tailings Concrete Filled Steel Tube Stub Columns Subjected To Axial Compression

With the rapid development of economy,the increasing demand of molybdenum metal leads to the nowhere stacking of molybdenum tailings.Using molybdenum tailings to replace the raw materials of common building materials in a certain proportion to prepare new building materials with excellent performance has become a research hotspot,and molybdenum tailings concrete is one of them.Concrete-filled steel tube(CFST)columns have many advantages,such as short construction period,high bearing capacity,good seismic performance and so on.They are widely used in modern constructions.The existing specifications for concrete filled steel tube are designed with ordinary concrete as core concrete.If molybdenum tailings concrete is directly used as core concrete,the bearing capacity of molybdenum tailings CFST columns may be overestimated by using existing formulas.In this paper,the relationship between the substitution rate of molybdenum tailings and the bearing capacity of molybdenum tailings CFST tubes is highlighted by using the method of control variables.Experiments were carried out,detail is as follow:(1)Using molybdenum tailings to replace fine aggregates in concrete,two kinds of molybdenum tailings concrete with different strength were prepared with four different substitution rates.The mechanical properties such as cubic compressive strength,axial compressive strength and elastic modulus of molybdenum tailings concrete were obtained,and the influence of molybdenum tailings substitution rate on the compressive strength of molybdenum tailings concrete is analyzed.(2)32 specimens of molybdenum tailings reinforced concrete(RC)columns and molybdenum tailings CFST columns were designed.8 groups of stub columns were subjected to axial compression.The failure modes,ultimate bearing capacity,peak strain and ductility of the specimens with the same steel quantity and cross-section area are compared.(3)By comparing the calculated values of the formulas given in the regulations of CFST in various countries with the results of ultimate bearing capacity of specimens subjected to axial compression,the formulas that the calculated values are closest to the experimental values are found,and the modified formulas suitable for caculating bearing capacity of molybdenum tailings CFST stub columns with different substitution rates are given through analysis.