Fire Resistance Experimental Research On Simply-Supported Recycled Concrete Beam

The research and development of recycled concrete technology has extremely importantpractical significance,which is necessary for the sustainable development of constructionindustry.There has almost no research on the high-temperature performance of recycledconcrete,especially for the fire resistance of components or structure,the behaviour of buildingelements under fire is still unclear.For the current situation of lacking fire resistance research of recycled concretecomponents, fire resistance test of two full-scale C30simple supported recycled concretebeams is carried out, according to the standard time-temperature curve given by GB/T9978.1-2008.The fire resistance of simple supported recycled concrete beams have beeninvestigated by comparing with the corresponding reinforced concrete beams about thephenomenon of test, the fire resistance and the temperature of measuring points.The studyhave shown that:after the test,the cracks of recycled concrete beam are more clear and regular,smaller number and larger spacing,shorter crack region and larger width.The rate of deflectionincrease and temperature rise are slower than the corresponding ordinary reinforced concretebeams.The recycled concrete beam has a fire resistance of2.5hours,which is longer thanordinary reinforced concrete beam,whose is2.1hours.On the basis of the test, ANSYS finite element software is used to calculate thetemperature distribution in cross-section and displacement changes, which are comparedwith the results of tests and analyzed. The study have shown that: ignoring the influence ofevaporation and cracks, ANSYS can accurately simulate the temperature distribution ofrecycled concrete beams,the variation of which is similar to ordinary reinforced concretebeam.In addition,the steel bond strength of recycled concrete is tested through six recycledconcrete blocks exposed to fire.