Flexural Behavior of Steel Fiber-Reinforced Lightweight Aggregate Concrete Beams Reinforced with Glass Fiber-Reinforced Polymer Bars

Nine beams reinforced with glass fiber-reinforced polymer (GFRP) bars and one reinforced with steel rebars fabricated using high-strength lightweight aggregate concrete (HSLC) were tested under four-point bending with different steel fiber contents, reinforcement ratios, and bar diameters to investigate their flexural strength and serviceability performance. The test results showed that specimens with steel fibers exhibited a lower deflection and a higher load-carrying capacity. The reinforcement ratio significantly affected serviceability performance, but bar diameter had a marginal effect. Generally, at service-load levels, the specimens exhibited acceptable midspan deflections but greater crack widths compared to the limits recommended by the codes. The experimental ultimate strengths, midspan deflections, and crack widths were used to assess the accuracy of prediction equations in standards in the US, China, and Canada. Rational deflection models for GFRP-reinforced normal weight concrete (NWC) beams were proposed based on the results from the available literature and were modified by introducing two correction factors of 0.85 and 1.35 for the GFRP-reinforced lightweight aggregate concrete (LC) and steel fiber-reinforced lightweight aggregate concrete (SFLC) beams, respectively. (C) 2018 American Society of Civil Engineers.