Behavior Of Geopolymer Recycled Brick Aggregate Concrete Filled Stainless Steel Tubular Columns Under Axial Compression

Solid waste disposal and greenhouse gas emissions occur in global climate change as a result of fast expansion of industry and infrastructure,and as concrete is made with Ordinary Portland Cement(OPC)as the binder.Geopolymer concrete is thought to have a lot of potential for making "green" concrete with a lower carbon footprint.Fly ash,slag,and alkali activator,three types of industrial waste that are green and environmentally friendly,are used to make geopolymer concrete,which can either partly or entirely replace ordinary concrete.It has both environmental and economic benefits to use fly ash and slag as cementitious materials.Combining stainless steel tubes with Geopolymer recycled brick aggregates combine the advantages of the outstanding corrosion resistance of stainless steel and the composite action in concrete-filled steel tube(CFST)system,and environmentally friendly.The performance of Geopolymer recycled brick aggregates Concrete-filled stainless-steel tube(CFSST)under axial compression is analyzed in this paper.The main study is as follows,taking into account the influence of variables like cross-section type of the member,types of concrete,Replacement ratio of recycled brick aggregates,diameter(width)to Tube thickness ratio and types of steel.The research work in this paper includes:(1)Experimental studyAn experimental study was conducted on 20 steel tubes;including 16stainless steel tubes and 4 ordinary steel tube filled recycled brick aggregate concrete(Geopolymer or ordinary concrete)under axial compression.The analysis of the main parameters includes type of steel material(stainless and ordinary steel),cross section form,steel tube thickness,type of concrete(geopolymer and ordinary concrete).The failure mode,ultimate bearing capacity,stiffness,ductility coefficient and peak strain are analyzed.(2)Finite element analysisThe stainless-steel tube and ordinary steel tube filled geopolymer recycled brick aggregate concrete and ordinary brick aggregate Portland concrete axial compression finite element of 20 models were created.Reasonably determine the constitutive relationship model of ordinary steel tube and core concrete.This project intends to adopt the constitutive model of steel tube and core concrete proposed by Tao Zhong.considering the stress of steel tube and concrete under axial compression and pure bending.Force state and interaction,using the finite element analysis software ABAQUS to establish the mechanical analysis model of the geopolymer recycled brick aggregates concrete filled stainless steel tube column.(3)Parametric analysis and practical design methodThe finite element model is used to investigate the factors that influence the axial compression of a geopolymer recycled bricks aggregate concrete filled stainless steel tube and a simplified design method for bearing capacity and ultimate bearing capacity corresponding to strain is proposed,which serves as a reference for related engineering practice and specification formulation.A finite element model was established for 225 and 225 circular and square cross-section axially compressed steel tube geopolymer concrete short columns containing broken brick recycled aggregates,and the ultimate bearing capacity,stiffness and peak strain were analyzed,and compared with the existing Comparison of design methods,if the design method is suitable for this type of component,is directly adopted.