Research On Mechanical Properties Of Steel Slag Concrete Of Circular Steel Tube Under Axial Compression

Concrete-filled steel tube has been widely used in various practical projects because of its high bearing capacity,good toughness,strong plasticity,good seismic performance and convenient construction.However,due to the different Poisson’s ratio of materials,the interfacial bonding between concrete and steel tube is incomplete in the initial elastic stage.Steel slag is a by-product of steel-making process.In engineering,because steel slag contains active minerals similar to cement,it has hydraulic cementitious property,so it is often used as cement admixture and instead of aggregate to mix steel slag expansive concrete.In terms of compressive strength and durability,steel slag aggregate concrete is superior to ordinary sandstone aggregate concrete.Therefore,the steel tube steel slag concrete composite structure can not only give full play to the advantages of the two materials,but also promote the reuse of solid waste,reduce the project cost,and have significant economic and social benefits.In this paper,based on the expansive property of steel slag concrete,combined with the constraint effect of steel tube on concrete,the axial compression test of steel slag concrete with round steel tube was carried out,the jk-10000 k N multifunctional structure experimental system was used to study its mechanical properties under axial compression.The main research contents are as follows:1.The axial compression test of steel slag concrete short column with round steel tube was used to analyze the influence of steel slag replacement rate,steel tube diameterthickness ratio,and specimen size on its mechanical properties.The curve further analyzes the concrete replacement rate,the steel tube diameter-thickness ratio,and the influence of the specimen size on its bearing capacity.The test results show that the use of steel slag to replace natural coarse aggregates can effectively improve the axial compression performance of concrete-filled steel tube columns.The effect is particularly obvious when the ratios of coarse and fine steel slags to replace aggregates are 75% and 100% respectively;with the diameter-to-thickness ratio of steel pipes The load-bearing capacity of the specimen decreases,and the failure mode of the specimen also changes.Comparing specimens with different section sizes and equivalent steel content,it can be seen that the size effect has a smaller effect on the stress of the specimen,and is compared with concrete The replacement rate is closely related.2.By comparing the calculated value of the calculation formula for the axial compression bearing capacity of concrete filled steel tube in the current domestic and foreign codes with the experimental value of steel slag concrete filled steel tube.the result shows: the calculation results of the GB 50936-2014 code and the AIJ code formula are consistent with the experimental values,which can provide a reference for the calculation of the bearing capacity of the steel slag concrete short column of the round steel tube.3.Using ABAQUS finite element software to simulate the steel slag concrete model of round steel tube under axial compression.the result shows: The damage shape,loaddisplacement curve and ultimate bearing capacity of the simulated specimen are not much different from the test results,thus demonstrating the reliability of the finite element model.On this basis,expand the number of models to further analyze the influence of the diameterto-thickness ratio and the specimen size on the mechanical properties of the specimen.