| Recycled concrete refers to concrete that has been mixed with recycled aggregates from waste concrete during the configuration process.Compared with natural aggregates,recycled aggregates are more convenient and cheaper.Recycled concrete technology plays an important role in protecting the ecological environment,saving natural aggregates and promoting the sustainable development of the construction industry.Because recycled aggregates have higher water absorption and defection than natural aggregates.Steel pipes are combined with recycled concrete in order to make more rational use of recycled concrete.Researches on the regenerated recycled concrete filled steel tubular(RRCFST)columns have been poorly studied under fire in domestic and foreign countries.In order to study and deeply analyze the fire resistance of the regenerated recycled concrete filled steel tubular columns,the fire resistance performance experiment and finite element simulation of regenerated recycled concrete filled steel tubular columns under axially compressed was carried out.The research work in this dissertation was outlined as follows:(1)Experiments of eight regenerated recycled concrete filled steel tubular columns was carried out.The experiments mainly consider three parameters: concrete strength,recycled aggregate replacement rate and load ratio.During the experiment,the failure process was observed,and the temperature-time curve,deformation-time curve,and fire endurance of the test piece were obtained.(2)The ABAQUS software has been used to establish the finite element model of the the regenerated recycled concrete filled steel tubular columns under fire.The temperature field and deformation-time curve obtained from the analysis are compared with the test results.The experimental data is used to verify the rationality of the model.(3)The effects of slenderness ratio,load ratio,recycled aggregate replacement rate,steel yield strength and concrete strength on the fire resistance of recycled steel tubular columns with rectangular steel tubes were analyzed by using the above model.(4)Based on the finite element analysis,the simplified calculation formula of the fire endurance of the reinforced concrete column of the axially compressed rectangular steel tube is given,and the correctness of the formula is verified.The fire resistance limit of the column can be estimated by the main influence parameters. |
PDF Full Text Request