Experimental Study On Axial Compression Performance Of Square Steel Tube Self-Compacting Rubber Concrete Column

Steel pipe rubber concrete(Ru CFST)is to waste rubber is applied to concrete filled steel tube,steel pipe for rubber concrete tight force,make the rubber granule and compatibility is not good to improve the properties of cement paste,the bearing capacity of concrete core rubber increased significantly,energy dissipation ability will be improved,full use of the viscoelastic energy dissipation capacity of rubber,has excellent aseismic performance.At the same time,the use of steel tube rubber concrete will turn waste tire rubber into treasure,which is conducive to the realization of green building concept and promote the sustainable development of the construction industry.In this paper,the axial compressive properties of self-compacting rubber concrete steel tube columns are studied.The main research results are as follows:(1)The mixing ratio design of self-compacting rubber concrete was carried out,the strength grade was C40,and the raw material test was carried out at the same time.The conclusion was drawn that self-compacting rubber concrete could give play to its superior performance and effectively delay the cracking of concrete.Although the compressive strength of self-compacting concrete mixed with rubber decreases somewhat,the corresponding material properties are guaranteed under the condition of small rubber replacement rate(10%).(2)16 rubber self-compacting concrete filled square steel tubes specimens were subjected to monotonic axial compression test,get relevant test data,analysis of the test variables(rubber replacement ratio,water cement ratio,aspect ratio)on mechanical properties of rubber concrete,get the following conclusions:with the increase of rubber,the ultimate bearing capacity of the specimen is reduced,the rubber to replace rate under the condition of small,can approximate think rubber concrete filled square steel tubes carrying capacity of the specimens won’t happen loss,mixed with rubber falling load-displacement curve segments may be gentle,to improve the bearing capacity of the specimen degradation adverse conditions;When the water-cement ratio changes in a small range,the load-displacement curve of rubber concrete-filled steel tube does not change,and the ascending section of the load-displacement curve is almost the same.Height to width ratio on the specimen is bigger,in the case of height to width is larger,the specimen in the early loading specimen in slight bend,due to the limited scope of slip line extensions on the surface of the steel tube,the destruction of the specimen tend to occur in the upper and lower ends of the specimens,with the increase of aspect ratio,specimen ultimate bearing capacity increases after the first reduce trends;The addition of rubber can improve the ductility of concretefilled steel tubular(CFST)specimens.With the increase of rubber replacement rate,the ductility of the specimens increases first and then decreases,and the "best replacement rate" of rubber is 15%.(3)Taking rubber particle size and rubber substitution rate as test variables,the reloading test was carried out for 9 square steel tube self-compacting rubber concrete column specimens.The conclusion is as follows: the addition of rubber will reduce the ultimate strength of the rubber filled steel tube concrete specimen.Compared with the specimen with low content,with the increase of the rubber replacement rate,the rising section of the specimen will gradually become full,which can be realized as the increased energy dissipation capacity.Rubber powder(grain)elasticity,easy to deformation,the rubber for the compressive deformation of concrete in concrete space,the cushion,rubber particles can effectively reduce the friction loss in the process of crack sliding,slow down the damage development of core concrete,so as to make the specimen stiffness degradation in the late reloading,rubber particle size and rubber content had no significant effect on fitting parameters,the ductility of the specimens is good.(4)Part lists the standard formula at home and abroad and the derived formula,the calculation of its load carrying capacity of ordinary square concretefilled steel tube column,the measured data and the calculated value of literature,through the experiment discovered specification AIJ,2001,2004,lin-hai han formula GB50936,lv Westwood calculated by formula is derived,higher reliability,more close to the measured data,and it is concluded that the effective set of self-compacting concrete filled steel tube column coupling coefficient is0.635;In practical engineering application,15%-22% is considered as the preliminary calculated safety factor.