NEUROQUANTOLOGY | OCTOBER 2022 | VOLUME 20 | ISSUE 12 | PAGE 3065-3071| DOI: 10.14704/NQ.2022.20.12.NQ77306 Pradugn Varhade et al / Shear Performance Of R.C. Deep Beam Using Hybrid Fiber As Reinforcement eISSN1303-5150 www.neuroquantology.com 1 Shear Performance of R.C. Deep Beam Using Hybrid Fiber as Reinforcement Pradugn Varhade 1 , S.B. Javheri 2 , S.K. Kulkarni 3 Abstract Researcher have established that the use of fibre reinforced concrete for casting of R.C. deep beams can prevent early cracking, improve the shear strength of deep beam and increase strain carrying capacity of concrete. Furthermore, it is found that using Hybrid fibre reinforced concrete (HFRC), reinforced with two or more different types of fibres, can produce superior results. The use of combination of small, discrete, randomly oriented fibres improves the strength and resistance against deformation of concrete members. The present study focuses on inclusion of hooked end steel fibre (SF), fibrillated polypropylene fibres (PP) and alkali resistance glass (GF) fibres in predefined proportion in the concrete mix to cast HFRC deep beams and study the effect on strength of deep beams. It is observed that HFRC deep beams, cast with a workable mix with a maximum fibre content of 1% steel + 0.3% PP + 0.16% glass fibre by volume of concrete, exhibit improvements of 49.67% in first crack load and 88.13% in load at failure when compared to conventional deep beams with a shear span to depth ratio of 0.5. KeyWords:Deep beam, HFRC, two point load, shear strength, ultimate load capacity DOI Number: 10.14704/NQ.2022.20.12.NQ77306 NeuroQuantology2022;20(12): 3065-3071 1. Introduction In structural applications like pile tops, foundation wall, corbels, transfer girders and tall buildings, reinforced concrete deep beams are useful. The slender beam theory based on Navier’s hypothesis is not relevant to deep beam. The behavior of deep beam is significantly different because of their large depth in relation to span. Generally deep beam are heavily loaded structural members and strength of deep beam it’s usually controlled by shear. The diagonal compression and tension in a perpendicular direction results from the shear action in the beam web. Throughout their lifespan, conventional R.C. deep beam structures experience severe deterioration. Conventional shear reinforcement cannot provide efficient resistance to cracks formation and unable to provide isotropic elastic properties to concrete [1]. This results in low shear strength, low reserve strength, low first crack load and sudden failure. The incorporation of fibres significantly improves the mechanical performance, including the tensile strength, fracture toughness, and fatigue resistance of the reinforced concrete. The fibres serve as not only the crack control reinforcement, but also the vehicle to allow for significant internal plastic stress redistribution to increase the strength of the specimens after the first crack forms[2,3]. HFRC is a type of reinforced concrete with two or more different kinds of fibres. It is recognized that HFRC can help produce better results [4]. S.K. Madan , G. Rajesh Kumar and S.P. Singh[5] found that shear strength increases with increasing fibre volume and decreasing shear span to-effective depth ratio.AvinashGornaleet al.[6] recorded good amount of increase in compressive strength, flexural strength and split tensile strength due to addition of glass fibres in concrete mix. Dr. Srinivas Rao et al.[7] examined durability of glass fibrereinforced concrete and found that durability of concrete was increased by addition of alkali resistant glass fibres. They also found that addition of glass fibres reduces segregation/bleedingand improves acid resistance of concrete. Suhail Shaikh et.al. [8] Corresponding author: PradugnVarhade Address: 1 PG Student, Dept. of Civil Engineering, Walchand Institute of Technology, Solapur, Maharashtra, India, 2,3 Research Scholar, Asst. Professor, Dept. of Civil Engineering, Walchand Institute of Technology, Solapur, Maharashtra, India E-mail: pradugn.varhade@gmail.com 1 , sbjavheri@witsolapur.org2, skkulkarni@witsolapur.org 3 3065