Experimental investigation of fibrous reinforced concrete beams under torsion loads

This experimental work investigates the effect of hybrid fiber between polypropylene fiber (PPF), and glass fiber (GF) on the torsional behavior of fiber-reinforced concrete (FRC) beams. Five reinforced concrete (RC) beams were subjected to a test of pure torsion and loaded until failure. The tested beams had various fiber contents: Specimen 1 is a control beam (without fiber), specimen 2 contains 1% GF, specimen 3 contains 1% PPF, specimen 4 contains 1% GF and 1% PPF, and specimen 5 contains 1.5% GF and 1.5% PPF in terms of volume. In the experimental tests, the torsional moment, crack pattern, ductility, and energy absorption of specimens were determined. Tests demonstrated that using a hybrid of PPF and GF enhanced the torsional moment, ductility, and energy absorption of RC beams. Consequently, the maximum torsional strength increased by 29.14%, and 39.43% when (1% PPF and 1% GF), and (1.5% PPF and 1.5% GF) were added, respectively.