Axial Compressive Behavior Of FRP-confined Lightweight Aggregate Concrete:An Experimental Study And Stress-strain Relation Model

Because of its lightweight, high strength, excellent corrosion resistance and a series of advantages, FRP(Fibre Reinforced Polymer) is widely used in reinforced concrete and the production of FRP confined concrete in the construction field. Previous studies indicate that the strength and ductility of the normal concrete columns under the restriction of FRP are improved very well. However, due to the high density of normal concrete, the strength to density ratio of the composite component is difficult to be promoted. Structural lightweight aggregate concrete has the characteristics of high strength and light weight, but its development and application are limited because of its brittleness and poor workability. According to the existing researches on the FRP confined concrete column, it is reasonably to believe that FRP confined lightweight aggregate concrete column can greatly reduce the weight of structure and provide sufficient strength and ductility. In the field of the mechanical properties of FRP confined lightweight aggregate, at present there is no related research. This paper present the procedure, result and analysis of experimental study on the behavior of CFRP confined lightweight aggregate concrete(LWAC) column and CFRP-LWAC-steel double-skin tubular column under Axial compression.Firstly, the axial compression tests of CFRP confined LWAC columns are designed in this paper, including two parameters: the types of lightweight aggregate concrete and the thickness of the CFRP. The material properties, manufacture process of the specimens and the test process are stated. Then describe the experimental phenomenon in detail, analyze the failure modes and the mechanical performance considering the influence of types of LWAC and CFRP thickness.Then, comparing with the with the strength and strain model of FRP confined normal concrete after the analysis of the experiment data, it is found that it is not suitable for CFRP confined LWAC. It’s necessary to establish a new ultimate strength and ultimate strain model. The results show that the calculated values agreed well with experimental data using the stress-strain model of Wu-Zhou.Finally, in order to further reduce the weight of the component, improve the efficiency of construction, a CFRP-LWAC-steel double skin tubular column is designed. The research parameter is hollow rate. A detailed description of the test process, test phenomenon and failure mode is made. This paper analyzes the reinforcing effects of compound of CFRP pipe, lightweight aggregate concrete and steel tube, and analyzes the effect of the hollow ratio on the strength and ductility of the composite column. There is almost no effect on the ultimate strength when the hollow rate is in the 0~47% range. Then supplement the ultimate strength and ultimate strain models established based on the upper paper.