Shear Behavior of Geopolymer Concrete Beams Reinforced with Glass Fiber-Reinforced Polymer Bars

The shear behavior of geopolymer concrete beams reinforced with glass fiber-reinforced polymer ( GFRP) bars and stirrups was investigated. Six short beams with a shear-span-to-effective-depth ratio (a/d) of 1.8 were cast: one with no stirrups, three with different stirrup spacing, one with less reinforcement, and one with steel stirrups. In addition, a slender beam (a/d = 4.7) with the same cross-sectional area was built to investigate the influence of a/d. Experimental results showed that the GFRP stirrups enhanced both the shear strength and deflection capacity of the beams by approximately 200%. The shear crack initiated at a higher load and with a finer crack width in the beam with narrower stirrup spacing. The short beam yielded higher shear strength than the slender beam with a similar transverse reinforcement ratio. The beams with GFRP stirrups yielded a shear strength and deflection capacity-including an analogous load-deflection response-similar to that of the beam with steel stirrups.