Mechanical Properties Of Self-compacting Steel Tube Self-Compacting Iron Tailings Concrete Short Column Under Compression And Bending

Self compacting iron tailing concrete is a new type of concrete material which is made up of iron tailing as coarse aggregate and iron tailing powder with certain fineness as admixture on the basis of ordinary self compacting concrete.It can not only effectively solve the problem of shortage of sand and stone resources in China,but also relieve the shortage of supply of concrete mineral admixture in most parts of the country.The self compacting iron tailing concrete is placed in the steel tube.On the one hand,it can make use of the superior working performance of the self compacting concrete to effectively avoid the pouring quality problems during the concrete pouring.On the other hand,it can make use of the restraint performance of the steel tube to ensure the interaction between the steel tube and the core concrete.Since scholars at home and abroad have little research on self-compacting steel tube concrete tailings,further research is needed.The iron tailings powder substitution rate(0%,50%,100%)was used as a variable to test the working and mechanical properties of self-confined iron tailings concrete.Taking iron tailings powder substitution rate(0%,50%,100%),steel content(12%,17%,22%)and eccentricity(20 mm?40mm)as three variables,the influence law on the mechanical properties of 5 square steel tube self-confined iron tailings concrete axial compression specimens and 10 bias specimens was studied to verify whether the cross capacity was compared with the BS5400(2005)?AISC(2005)of rules based on superposition theory and GB50936-2014?GJB4142-2000?DBJ13-51-2003 calculation based on uniform theory.The results show that with the increase of the substitution rate of iron tailings powder,the slump expansion of self-compacting iron tailings concrete increases,the expansion time decreases,and all of them can meet the design requirements.The failure form of self-compacting iron tailings concrete test block is similar to that of ordinary concrete.The cube compressive strength,axial compressive strength,splitting tensile strength and elastic modulus of self-compacting iron tailings concrete show a downward trend with the increase of iron tailings powder substitution rate.In the middle and upper part of the axial compression specimens,the bulging failure occurred,and the bending failure occurred in the bias specimens.The bearing capacity and ductility coefficient of the specimen,the stiffness of the specimen increase obviously with the increase of steel content;the increase of iron tailings powder substitution rate has little effect on the bearing capacity and ductility coefficient of the specimen,and the stiffness of the specimen decreases;increasing eccentricity,the bearing capacity and flexural stiffness of the specimen decrease and the ductility coefficient increases.For axial compression specimens,the calculated bearing capacity GB50936-2014 the code is in good agreement with the actual bearing capacity;for bias specimens,the calculated bearing capacity results obtained DBJ13-51-2003 the code are less discrete.Therefore,it is recommended GB50936-2014 calculate the bearing capacity of the short column of axial compression of steel tube self-confined iron tailings concrete,and DBJ13-51-2003 the calculation of the bearing capacity of the short column of partial compression of steel tube self-confined iron tailings concrete.