Confinement effects of glass FRP on circular concrete columns made with crushed fired clay bricks as coarse aggregates

This paper investigates the confinement effects of low-cost glass fiber reinforced polymer composites on circular concrete columns made with crushed fired clay bricks as coarse aggregates. Two types of locally available fired clay bricks such as solid fired clay bricks and hollow fired clay bricks were used to prepare the crushed fired clay brick aggregated. The crushed fired clay brick aggregates were replaced with natural aggregates by 50 %. In this study, a total number of 32 circular concrete columns were constructed and tested under monotonic axial compression. The other research parameters were strength of concrete (i.e., low strength and high-strength concrete) and number of layers of glass FRP composites such as two, four and six layers. Locally available bi-directional glass fiber and polyester resin were used to develop glass FRP composites. The salient features of glass FRP composites are low-cost, high strength and stiffness. The experimental results indicate that the use of glass FRP composite is very suitable to modify the ultimate load carrying capacity and stiffness of the circular concrete columns made with crushed fire clay bricks as coarse aggregates. In general, the confinement effects of glass FRP on circular concrete columns are found higher for concrete made with crushed fired clay hollow bricks as compared to the concrete made with crushed fired clay solid bricks. Also, increase in ultimate load carrying capacity is found lower for high-strength concrete circular columns as compared with the low-strength concrete circular columns. The analytical investigation reveal that the existing ultimate strength models are suitable to approximately predict the ultimate strength of glass FRP confined circular concrete columns made with crushed fired clay bricks as coarse aggregates. However, the existing ultimate strain models are not suitable to accurately predict the ultimate strain of glass FRP confined circular concrete columns made with crushed fired clay bricks as coarse aggregates.