Experimental and finite element modeling of concrete-filled basalt fiber reinforced polymer-polyvinyl chloride tube cylinders under axial compression

In this research, short cylinders of recycled aggregate concrete confined by basalt fiber reinforced polymer strips-polyvinyl chloride tubes mixture are taken as the object of investigation, and a mixture of experimental study, finite element simulation and theoretical analysis is applied. Through modifying the volume quantity of basalt fiber reinforced polymer employed, axial compression studies were performed on short cylinders of confined recycled aggregate concrete. The results demonstrate that the variable spacing of basalt fiber reinforced polymer strips and the number of strip layers have a bigger effect on the load carrying capacity and ductility of the confined specimens. Taking the unconfined specimen as a control, the load carrying capacity of the basalt fiber reinforced polymer-polyvinyl chloride composite-confined specimen was enhanced by 17.56-66.74%, and the maximum ductility index reached 3.1. A modified stress-strain model was then built based on the extant model. Using the computational results evaluated against the experimental results, the average error in fitting the formulas produced in this study are below 10%. The results reveal that the composite confinement system has good confinement effect and has certain reference value.