Flexural Strength and Serviceability of GFRP-Reinforced Lightweight Self-Consolidating Concrete Beams

Abstract

Considering the limited experimental work carried out on fiber-reinforced polymer (FRP) bars in lightweight concrete (LWC) beams, there is a need for more investigation to understand their flexural behavior and serviceability performance. This paper reports on an investigation based upon an experimental study that evaluated the flexural capacity and serviceability performance of lightweight self-consolidating concrete (LWSCC) beams reinforced with glass-FRP (GFRP) bars. Ten reinforced concrete (RC) beam specimens (200 wide × 300 high × 3,100 mm long) were prepared and tested under four-point bending up to failure. Eight specimens were made with LWSCC, while the other two were made with normal-weight concrete (NWC) as reference specimens. The test variables were concrete density (LWSCC and NWC), reinforcement type (sand-coated GFRP, helically grooved GFRP, or steel bars), and longitudinal GFRP reinforcement ratio. The lightweight coarse aggregate (Solite 343) was used along with the two types of fine aggregate [lightweight sand (Solite 307) and natural sand (NS)] in the LWSCC mixtures, leading to a concrete density of 1,800 kg/m3. The test results indicate that the GFRP-RC beams failed as a result of concrete crushing. The normalized moment capacity of the GFRP-reinforced LWSCC beams was approximately 0.90 times that of the counterpart GFRP-reinforced NWC beams. The predicted moment capacities of the GFRP beams were estimated based on the strain-compatibility approach in the design standards, which showed good agreement between the predicted and experimental results. Moreover, the recorded deflections and crack widths of the GFRP-reinforced LWSCC beams are presented and compared to those predicted with the FRP design provisions and the literature. The comparisons reveal that the deflections and crack widths of the GFRP-reinforced LWSCC beams can be estimated with the FRP design provisions with a variable degree of conservativeness.