Performance of eco-friendly lightweight concrete in-filled Fiber Reinforced Polymer composite columns under axial compression-An experimental, numerical, and theoretical approach

In this study, innovative Lightweight Self-compacting Geopolymer concrete made of industrial and agricultural wastes is developed and used as the in-fill material in Fiber Reinforced Polymer (FRP) composite columns. The axial compressive performance of the columns is investigated with critical parameter variations such as the effect of the Diameter to thickness (D/t) ratio and fiber orientation of the FRP tube. Two types of D/t ratios, i.e., 30 and 50, and three fiber orientations +/- 0 degrees, +/- 30 degrees, and +/- 45 degrees were used for the key parameter variations. An increased D/t ratio from 30 to 50 reduces the performance in terms of load despite increasing the deformation. The columns containing the fiber orientation of +/- 0 degrees exhibit greater performance compared to other types of fiber orientation (+/- 30 degrees and +/- 45 degrees). The experimental results and failure patterns were compared and validated against the numerical and theoretical studies. A Finite Element model is developed and validated with the experimental results with errors ranging from 0.84% to 4.57%. The experimental results were validated against various existing theoretical prediction models with a percentage error of 7% to 14% An improved theoretical model is proposed for predicting the axial load of concrete-filled FRP composite columns.