| Abandoned bricks are construction wastes generated during demolition and renovation of old cities,and the disposal of industrial wastes such as fly ash and slag deserves attention.If part of broken waste bricks are used as coarse aggregate,fly ash and slag are used as cementitious materials,it has both environmental and economic benefits.Combining steel tubes with this type of concrete can overcome some of the drawbacks of recycled concrete and better promote its application in practical engineering.In this paper,the axial compression static performance of steel tube geopolymer concrete members containing recycled aggregate of broken bricks is studied.Considering the influence of factors such as benchmark strength,recycled aggregate replacement rate and diameter-to-thickness ratio,the main work is as follows:(1)Experiments were carried out on 25 geopolymer recycled concrete with broken brick aggregate confined by steel tubes,and the failure mode,bearing capacity variation law,peak strain variation law,etc.were analyzed,and the existing ultimate bearing capacity formula of recycled concrete confined by steel tubes was revised,and proposed fiber model constitutive.(2)An experimental study was carried out on 40(20 circular section,20 square section)geopolymer concrete-filled steel tubes axial compression short columns containing recycled aggregate from broken bricks.The failure mode,ultimate bearing capacity,stiffness,ductility coefficient and peak strain are analyzed.(3)In this paper,combined with the test and theoretical analysis,the existing constitutive model of steel tube-constrained ordinary core concrete is modified,and compared with the test specimens of 25 concrete confined by steel tubes to verify the accuracy of the model.And the40 short columns of concrete-filled steel tubes are simulated by the finite element software ABAQUS using the formula before and after the modification.The calculation results of the bearing capacity are in good agreement with the test results,and the modified stiffness calculation results are in better agreement with the test results.(4)432(240 circular sections and 192 square sections)geopolymer concrete-filled steel tubes axial compression short columns containing broken brick recycled aggregates were analyzed using the finite element software ABAQUS,and the finite element calculation results were compared with the existing calculation methods.By comparison,the existing calculation method for bearing capacity and stiffness can be used,and the calculation method of peak strain can be further modified. |
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