Experimental Research On Interfacial Properties Of Concrete-Filled Steel Tube Structure After High Temperature

Concrete-filled steel tube structure (CFST) is a new structure form developing in recent decades, due to its high bearing capacity, good anti-seismic performance, convenient construction, good economic benefits and many other advantages, which are widely used in various construction projects. The bond of CFST is a complex interaction interface between steel and concrete, through which the interaction interface of two kinds of material to achieve transfer force and to coordinate the deformation, it is the premise of two materials of steel tube and concrete components to work together, has great influence on the deformation and the bearing capacity in member.Generally speaking, after the high temperature fires, physical and mechanical properties of structural components such as deterioration of bonding properties between steel tube and concrete will deteriorate, resulting in deformation of the structure increases, causing redistribution of internal force of structure, decreasing the bearing capacity of the structure, or even leading to the progressive collapse and overall structural damage, people has yet to fully master the architectural structure of the thermal reaction of fire, the current design methods also can not effectively reveal the internal mechanism of the structure collapsed. With CFST application gradually increased in practical engineering, it urgently need to carry out study on bond between steel and concrete performance after high temperatures (fire).This paper first prepared C60self compacting concrete (SCC) in a wide range of engineering applications recent years, and study the physical and mechanical properties after the high temperature, followed CFST conducted at different temperature, different heat treatment ways of fire simulated experiment by the muffle furnace and combustion furnace, finally, it carried out push-out test of16CFST.Through the experiment summed up the variation of physical and mechanical performance of SCC before and after high temperature, proposed a measure of "reserved holes" to prevent the bursting of the high temperature of SCC. In addition the test got the rule of the bond strength and the relative ultimate slip varies with temperature change, provide the bond-slip constitutive relationship contains high temperature (fire) impacts.