Research On Compressive Behavior Of FRP Confined Recycled Geopolymer Concrete With Tailings Powder

The high-speedexpansion of urbanization and industrialization has led to the demand for natural aggregates increased,and the price of recycled aggregate continues to rise.Because of its low strength and ductility,the preparation of recycled aggregate from construction waste has become an obstacle to promote the resource utilization of construction waste and alleviate the shortage of natural aggregate resources.Because of its large reserves and difficult treatment,tailing has become a big problem of environmental governance.Geopolymer concrete has strong interface binding force,which can be closer combined with aggregate interface,which can make up for the defect of low strength of recycled aggregate.Secondly,tailings powder is a good raw material for geopolymer concrete.Therefore,recycled aggregate and tailings powder are used in geopolymer concrete to prepare ground mixed with tailings powder Polymer recycled concrete（GRC-TP）can make up for short slab,realize complementary advantages and improve resource utilization.Geopolymer concrete has higher brittleness and worse ductility than natural aggregate concrete,and external restraint is a common way to improve the strength and ductility of concrete structure.Fiber reinforced composite（FRP）is used extensively in project with the advantages of light weight,high strength,corrosion resistance,etc.,which can achieve good mechanical properties such as strength and ductility,and can be applied to corrosive environment The recycled aggregate concrete（FRP-GRC-TP）has a good application prospect.The main contents of this paper are as follows.（1）Study on the properties of raw materials.In this paper,the properties of recycled geopolymer concrete raw materials were tested,and the properties of CFRP and GFRP were tested by direct tensile FRP strip specimens,including tensile strength,tensile failure strain and elastic modulus.（2）Research on basic mechanical properties of GRC-TP.The cube compressive strength(f_cu),splitting tensile strength（f_t）,axial compressive strength（f_c）and elastic modulus（E_c）of 20 groups of specimens were tested with tailings replacement rate（r₁）and recycled coarse aggregate replacement rate（r₂）as variables.（3）Theoretical study on basic mechanical properties of GRC-TP.It is necessary to establish the early strength ratio prediction formula,analyze the relationship between f_t and f_cu,establish the relationship between f_c and f_cu,and establish the relationship between E_c and f_cu.（4）Research on mechanical properties of FRP-GRC-TP under axial compression.Taking FRP type,FRP layers and core concrete strength as variables,14 groups of cylinder specimens were tested and analyzed for compressive performance.The failure mode,ultimate bearing capacity and ductility,lateral expansion and stress-strain of the specimens were analyzed.（5）Theoretical analysis of FRP-GRC-TP under axial compression.At first,the classical design model and analysis model of FRP confined concrete are listed,and the experimental values of axial compressive streng th and axial ultimate strain are compared with the calculated values of the model,and the error s between them are analyzed.At last,taking the classical model with small error as the prototype,regression analysis and modification are carried out to obta in the axial compression strength calculation formula and axial ultimate strain calculation formula suitable for FRP-GRC-TP.