Shear behavior of RC beams prepared with basalt and polypropylene fibers

Abstract

Basalt and polypropylene fibers are relatively cheap, durable, and corrosion-resistant materials, and they can increase the shear strength of reinforced concrete (RC) beams. Although recent studies investigated the mechanical behavior of fibrous concrete, limited research was conducted to explain the shear behavior of RC members prepared with basalt or polypropylene fibers. This research is designed to study the shear behaviour of RC beams prepared with basalt and polypropylene fibers and to find the optimum percentage for each type of fiber. Eight RC beams were tested to explain the shear behavior of RC beams prepared with basalt and polypropylene fibers. The beams and cylinders were cast with three various proportions of basalt and polypropylene fibers 0.6%, 1.3%, and 2.5% of the total cement weight. Test results showed that the best proportions for basalt and polypropylene fibers were 2.5% and 0.6% of the total cement weight, respectively. The inclusion of polypropylene or basalt fibers considerably enhanced the ductility of thebeams. Polypropylene fibers are superior to basalt fibers in enhancing the shear strength and ductility of the RC beams. The inclusion of 0.6% polypropylene fibers enhanced the shear strength, peak deflection, ductility, and initial stiffness up to 23.2%, 39.74%, 195%, and 2.56%, respectively with respect to the reference beam prepared with ordinary concrete. The inclusion of 2.5% basalt fibers increased the shear strength, peak deflection, ductility, and initial stiffness up to 20%, 64%, 121%, and 21.2%, respectively, compared to the beam prepared with the ordinary plain concrete. Finite element (FE) models were then created to capture the behavior of the beam specimens. The proposed FE models can satisfactorily predict the observed behavior.