Experimental Study On Axial Compression Mechanical Properties Of Desert Sand Concrete Filled Steel Tubular Short Columns

Desert sand has been verified by many scholars to verify its feasibility in engineering construction.Xinjiang desert sand resources are abundant and the project cost is low,which can save the river sand resources that are getting scarce.Concretefilled steel tube has the advantages of high bearing capacity and good ductility,because of its relatively large internal space,it can conform to the shortcomings of desert sand concrete with low slump and poor fluidity.In this paper,by incorporating desert sand into ordinary sand,the concrete-filled steel tubular short columns with different desert sand substitution rates are compared with the ordinary sand CFST.The effect of the pressure properties of different desert sand replacement rates on the concrete-filled steel tubular short columns and basic mechanical properties of concrete are studied.The specific test content is as follows:(1)With different desert sand replacement rates,the compressive strength,splitting tensile strength test of concrete cube test blocks and the axial compressive strength test of cylindrical test blocks were carried out.The basic mechanical properties of desert sand concrete with different replacement rates(0%,20%,40%,60%,100%)were discussed.It was found that the replacement of ordinary sand with desert sand partially affected the strength of concrete to a certain extent,but the impact is not large.It is concluded that the strength of desert sand concrete with different replacement rates can reach the strength of ordinary sand concrete designed.(2)The axial compression test of the desert sand concrete-filled steel tubular short columns with different desert sand replacement rates was carried out,and the damage phenomenon of the short columns was observed and compared with the ordinary sand concrete-filled steel tubular short columns.The failure mode of the short columns was judged,and the ultimate bearing capacity,load-displacement curves,load-strain curvse and ductility of the desert sand concrete-filled steel tube short columns with different replacement rates were analyzed based on the experimental data.It is concluded that the incorporation of desert sand with different substitution rates can also make the mechanical properties of the CFST short column specimens reach the mechanical properties of the ordinary sand concrete-filled steel tubular short columns.(3)By using the calculation formulas of bearing capacity of concrete-filled steel tubular short columns in Europe,the United States,Japan and China,the theoretical value of ultimate bearing capacity of the desert sand concrete-filled steel tubular short columns is calculated.It is concluded that the theoretical values calculated by the technical specifications of China's concrete-filled steel tubular structures are most consistent with the experimental values.(4)Desert sand concrete can be applied to concrete-filled steel tubular members.