Axial Behavior of FRP Confined Concrete Using Locally Available Low-Cost Wraps

Abstract

This study investigates the influences of three types of locally available low-cost Fiber Reinforced Polymers (FRP) wraps and two concrete mix designs on the axial behavior of FRP confined concrete. The experimental program comprised four unconfined (control), four glass FRP Matt Strand (GFRP-MS) confined concrete, four glass FRP Rowing (GFRP-R) confined concrete and four carbon FRP (CFRP) confined concrete specimens with a diameter of 150 mm and a height of 300 mm tested under axial compression. The specimens were prepared using two normal strength concrete mix designs, i.e., Mix-A and Mix-B. The experimental results exhibited that an increase in the confined concrete strength per unit cost ratio of a single layer of GFRP-MS was about two times of a single layer of CFRP wrap, whereas the increase in confined concrete strength per unit cost ratio of single layer of GFRP-R was about four times of a single layer of CFRP wrap. GFRP-MS and GFRP-R wraps can exhibit similar confined strengths as CFRP wrap with six and twelve times lower costs, respectively, than CFRP wrap. Mix-B concrete specimens exhibited higher confined concrete strengths but lower confined concrete strain than Mix-A concrete specimens. A database of 140 FRP confined concrete specimens was developed based on a set of specific criteria to develop a design-oriented model to predict the FRP confined concrete strength. The predicted confined concrete strengths matched well with the experimental confined concrete strengths. The two layers of GFRP-R exhibited similar confined concrete strength as CFRP wrap. In addition, GFRP-R exhibited high cement strength index (CSI) and low embodied CO2 index (CI).