Serviceability and Strength of Polypropylene-Reinforced Self-Consolidating Concrete Beams Reinforced with Glass Fiber-Reinforced Polymer Bars under Bending Cyclic Loading

This study investigated the serviceability behavior and strength of polypropylene fiber (PF)-reinforced self-consolidating concrete (PFSCC) beams reinforced with glass fiber-reinforced polymer (GFRP) bars. Five full-scale concrete beams measuring 3100 mm long x 200 mm wide x 300 mm deep (122.1 x 7.9 x 11.8 in.) were fabricated and tested up to failure under four-point bending cyclic loading. Test parameters included the longitudinal reinforcement ratio (0.78, 1.18, and 1.66%) and PF volume (0, 0.5, and 0.75% by concrete volume). The effect of these parameters on serviceability behavior and strength of the test specimens is analyzed and discussed herein. All the beams were evaluated for cracking behavior, deflection, crack width, strength, failure mode, stiffness degradation, and deformability factor. The test results revealed that increasing the reinforcement ratio and PF volume enhanced the serviceability and flexural performance of the beams by effectively restraining crack widths, reducing deflections at the service and ultimate limit states, and decreasing residual deformation. The stiffness exhibited a fast-to-slow degradation trend until failure for all beams, at which point the beams with a higher reinforcement ratio and fiber volume evidenced higher residual stiffness. The cracking moment, flexural capacities, and crack width of the tested beams were predicted according to the North American codes and design guidelines and compared with the experimental ones. Lastly, the deformability for all beams was quantified with the J-factor approach according to CSA S6-19. Moreover, the tested beams demonstrated adequate deformability as per the calculated deformability factors. © 2025.