Comparison Study on Flexural Behavior of Steel and FRPs Reinforced Concrete Beam

Fiber reinforced polymers (FRPs) have become a practical alternative construction material for substituting steel bars due to their lightweight, high strength, high corrosion strength, and good durability. As a result, many previous studies were interested to investigate the flexural performance of FRPs reinforced concrete (RC) beam. However, the investigation of flexural behavior of FRPs RC beam is still required. Therefore, the aim of this paper is to compare the flexural behavior of steel and FRPs bar RC beam. Four specimens consisting of the steel-reinforced concrete beam (CB), glass fiber reinforced polymer (GFRP) reinforced concrete beam, basalt fiber reinforced polymer (BFRP) reinforced concrete beam, and hybrid BFRP bar-BFRP grids reinforced beam were fabricated and tested. The beam specimens were designed to have the same moment capacity. To capture the crack pattern development of all beam specimens, the Digital Image Correlation method was used. The experimental results show that BFRP bar and GFRP bar can be used to replace the steel rebar in case ultimate limit state, but not in serviceability limit state. This is due to lower elastic modulus and bonding strength between FRPs-concrete interface. It also illustrated that the lower bonding strength of the FRP bar-concrete interface could induce the bottom cracks at the flexural zone to propagate rapidly which causes the beam to fail before the crushing of the concrete.