| This study is based on the research project of the force mechanism and design method of the FRP-concrete composite box section double-layer traffic structure system(No.51578236).In order to solve the problem of instability of the compression member in the space truss of the GFRP tube,the self-compacting RPC is used to fill the pressurized GFRP tube.Therefore,the mechanical properties of the self-compacting GFRP tube RPC column are studied.The main research contents are as follows:(1)On the basis of the benchmark mix ratio,by adjusting the water-to-binder ratio,the amount of expansion agent,the amount of fly ash and comparing their strength,fluidity and other properties,a self-compacting micro-expansion active powder concrete with a fluidity of more than 255 mm and a strength of 80 MPa under natural curing conditions is obtained.(2)The mechanical properties of GFRP pipes with different forming processes were tested,and the mechanical parameters such as axial ultimate strength,ring tensile ultimate strength,axial compression modulus and ring tensile modulus of GFRP pipes were obtained.It is found that the tension of the wound pipe is better,and the axial compression force of the pultrusion pipe is better,because the GFRP material is an anisotropic material.In engineering applications,it can be applied to different structures according to the stress characteristics of different forming processes.(3)The axial compression test of GFRP pipe self-compacting RPC short column was carried out.The effects of pipe forming process,expansion agent dosage and force mode on the mechanical behavior of the members were studied.The test results show that: 1)GFRP pipe RPC short column is a kind of lateral stiffening force member,the bearing capacity and deformation performance of concrete column are improved,and the space stiffness of GFRP pipe as structural member will also be improved;2)The incorporation of expansion agent in core concrete has little effect on the overall bearing capacity of GFRP pipe self-compacting RPC short column,but it reduces the shrinkage deformation of concrete after hardening,and the deformation performance of the member is improved;3)The bearing capacity of the full-section common compression member is similar to that of the core concrete compression member,but the deformation ability of the member is stronger only when the core concrete is stressed.(4)Comparing the experimental and calculated values,it is found that the test value and calculated value of the GFRP tube self-compacting RPC short column are in good agreement,and the error range is about 5%,indicating that the GFRP tube self-compacting RPC column studied in this paper is applicable to the existing theoretical formula.It provides a theoretical basis for the application of the composite component in practical engineering. |
