Experimental Study On The Axially Compressed Circular Concrete Column Confined By Basalt Fiber Reinforced Plastic Sheet

Basalt Fiber Reinforced Plastic Sheet is a new kind of fiber reinforced materials. Because of its outstanding mechanical properties, physical properties and ideal ratio of property and price in concrete engineering, the research and application on basalt fiber reinforced plastic sheet (BFRP) are paid more attention. This paper presents an experimental investigation on axially compressed circular columns confined by BFRP which 20 sets of 40 concrete cylinder specimens with high and diameter aspect ratio 2 are researched on the strength and size effect of circular columns. Base on a performance test of concrete circular columns confined by BFRP under axial compressed load, the deformation and failure modes are depicted in details. The strength and size effect of stress and strain of concrete circular columns confined by BFRP are studied. The influence of BFRP layers confining the circular columns on ultimate strength and the stress and strain of concrete are discussed. The performance of concrete circular columns confined by BFRP and CFRP under axial compression is also studied. The effect of wrapped way of BFRP and CFRP on strength and deformation is analysied. The research conclusions are as following.1. Under the same circular constraint force, the ultimate stress and peak strain of C30 concrete circular columns are decreased as the size of columns increases. The size effect on the strength and stress-strain relation between concrete circular columns with similar shape is presented. The size effect of low-grade concrete circular columns confined by BFRP is more significant than the high-grade one.2. The strength, the transverse strain and axial strain of concrete cylinder confined have been improved with the increase of BFRP layers, especially the transverse strain. The amount of increase is decreased as the number of layers of BFRP.3. For the same grade concrete columns confined by BFRP and CFRP the ultimate strength and ductility of concrete columns confined by CFRP wrapped the inner and BFRP in the outer is better than BFRP wrapped the inner and CFRP in the outer.4. The concrete columns confined by hybrid BFRP and CFRP are recommeded under the consideration of the capacity, economic efficiency and ductility, which high strength FRP wraps in the inner and good ductility FRP in the outer.