Experiment and modeling on axial behavior of carbon fiber reinforced polymer confined concrete cylinders with different sizes

In most experiments, small-size fiber reinforced polymer-confined concrete cylinders are used to study the axial compressive behavior. Based on the experimental results, many strength models and stress-strain relationships of confined concrete have been established. Whether the experiment-based strength models and stress-strain relationships can be directly applied to large-size circular concrete columns, however, is still an open issue. To clarify this issue, this article studies the influence of specimen sizes on the axial behavior of carbon fiber reinforced polymer confined concrete cylinders. Three types of concrete cylinders with diameters of 100, 200, and 300 mm, wrapped with one ply, two plies, and three plies of carbon fiber reinforced polymer, respectively, are cast and tested. The experimental results show that, under identical lateral confining stress, the compressive strength and axial stress-strain relationship are independent of the specimen size. Based on theoretical analysis and experimental data, an analysis-oriented stress-strain relationship and an analytical strength model are developed to predict the axial compressive behavior of fiber-reinforced polymer-confined concrete cylinders. The validity of the stress-strain relationship and strength model is verified with the experimental results and 16 existing models obtained from the literature.