FRP Constrained Thin-wall Round Steel Tube Recycled Concrete Long Columns Under Axial Compression Stress Performance Research

In recent years, the rapid development of infrastructure construction, the real estate industry is developing rapidly, a lot of the old city demolition, which will produce a large amount of construction waste, has a serious impact on the natural environment that we live in. The use of river sand, gravel, water resources is limited, resulting in lack of building materials. How to deal with these waste materials, makes it again as a building material, sand and other natural resources to ease the demand, to meet the requirements of sustainable development. Scholars and engineers have payed more and more attention on it.In recent years, researchers have carried out studies on regeneration of building materials. Especially in the study of recycled concrete is particularly prominent.Through the construction waste crushing processing waste, produces the configuration of the thickness of aggregate concrete. But in the study, people have found many shortcomings, such as the mechanical properties of recycled concrete is worse, the larger variability of the strength of concrete, strength of mixing recycled concrete is also lower. In order to use these waste concrete effectively, realize the maximization of the mechanical properties and economy. Many scholars believe that the use of composite structures, the recycled aggregate concrete filled into steel tube and then stirring and vibrating compaction, the formation of recycled concrete steel tube. Through this method, the advantage of steel tensile strength and compression strength of concrete, can improve the mechanical properties of concrete, the full cooperation of concrete and steel.In engineering application and a lot of research in the laboratory, the limitations of structural style is found. For example: in the further the increasing load on the structure, bonding the structure of the loading area can not be increased accordingly, need thicker steel wall thickness to achieve the demand of bearing capacity. So as to improve the project cost, corrosion resistance, fire protection, earthquake are limited. So researchers consider whether there is a new type of technology, both can satisfy the requirement of load components, and do not change the original appearance shape, and lower cost but also make up for steel of various defects method? On this basis, the researchers in the concrete filled steel tube is coated with FRP FRP material, making the use of the tensile strength of the material features, constraint of the lateral deformation of composite column, increasing the bearing capacity of composite columns, playing the role of reinforcement.FRP of recycled aggregate concrete column filled steel tube is wound FRP material outside of steel pipe, Make the use of steel tube and FRP constraint on the core concrete, so as to improve the bearing capacity of member in the three axial compression.So this article mainly studies FRP parcel thin-wall round steel tube recycled concrete long columns under axial compression stress performance research.Therefore, based on the experimental research, theoretical analysis and finite element analysis, the constraints on FRP thin-wall round steel tube recycled concrete long columns axial compression performance are studied. Analysis of the recycled concrete replacement ratio, the length of column,the FRP layer number of packages and package method for the influence of factors on the experiment on the mechanical properties.