Experimental and Numerical Study of Torsional Solid and Hollow Section of Polyolefin Fiber-Reinforced Concrete Beams

An experimental and theoretical program was undertaken to enhance comprehension regarding how variations in fiber ratio impact the structural performance of both solid and hollow reinforced concrete beams when subjected to pure torsion. Polyolefin fiber was utilized in this study. To achieve this objective, a total of sixteen specimens of fiber-reinforced concrete beams were manufactured. Among these, eight were solid beams, while the remaining eight were hollow beams, all featuring rectangular cross-sections. These specimens were constructed employing polyolefin fiber. The findings indicated that incorporating polyolefin fiber into the concrete mixture led to improved mechanical properties in the cured concrete. The most significant enhancements were observed in the splitting tensile strength and flexural strength tests conducted on the specimens. Both solid and hollow beams exhibited notable enhancements in their torsional performance. These enhancements occurred as the polyolefin fiber percentage increased from zero to 1.5%, while the transverse and longitudinal reinforcement ratios remained constant. Furthermore, the reduction ratio of torsional strength becomes more noticeable when comparing solid and hollow sections in high-strength beams, as opposed to normal-strength beams.