Experimental and analytical flexural analysis of steel and GFRP reinforced reactive powder concrete beams

Glass fiber-reinforced polymer (GFRP) bars, categorized as non-metallic materials, are being explored as a substitute for steel bars in concrete structures because of their strong tensile strength and long-term durability property. This research investigates the flexural and deflection response of reactive powder concrete (RPC) beams reinforced with 10 mm diameter steel and GFRP bars. In total, six RPC beams with 100 × 100 mm cross-sectional dimensions were tested under four-point lateral loading across a 300 mm bending span with simple support: two reinforced with GFRP bars, two reinforced with steel bars, and two without reinforcement. The tests indicated that both GFRP and steel bars led to a significant increase in lateral load capacity compared to the control beam by 183.25% and 134.06%, respectively. Additionally, reinforced beams showed marked improvements in energy absorption capacity, with steel and GFRP providing ∼200- and ∼270-fold enhancements, respectively, over the control specimen. Furthermore, the inclusion of GFRP and steel reinforcement altered the failure mode from bending to a combination of concrete crushing and diagonal tension. The experimental-to-theoretical moment capacity (M exp /M th ) demonstrated a strong dependence on reinforcement type, validating ACI provisions for steel-reinforced beams (mean = 1.09) but revealing non-conservative predictions for GFRP-reinforced beams (mean = 0.81).