International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 13 Issue: 01 | Jan 2026
p-ISSN: 2395-0072
www.irjet.net
Experimental Study on Low-Velocity Impact Behaviour of SFRC Slabs Reinforced with HYSD, Hybrid and GFRP Bars Nagabhushan V S1, Dr. Kiran T2 1Student of Master in Technology, Department of Civil Engineering, University of Visvesvaraya College of
Engineering, Bengaluru, Karnataka, India.
2Associate Professor, Department of Civil Engineering, University of Visvesvaraya College of Engineering,
Bengaluru, Karnataka, India. ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract- Impact loading at low velocity is one of the
investigations done to understand the impact response of reinforced concrete slabs.
important design considerations for reinforced concrete elements under accidental and service-level dynamic actions. The paper reports an experimental study on the impact performance of steel Fibre reinforced concrete (SFRC) slabs internally reinforced with HYSD, hybrid (HYSD+GFRP), and GFRP bars in ambient temperature exposure. A total of six square slab specimens of size 500 × 500 × 50 mm were prepared using M30 grade concrete; two specimens for each type of reinforcement, with and without 0.65% steel Fibre volume fraction. All slabs were internally reinforced with a single layer of reinforcement near the tension face and tested under repeated low-velocity impact loading from a drop weight of 10 kg released from a height of 1 m. The impact performance was assessed in terms of the number of blows at which the first visible crack appeared and the total number of blows withstood prior to failure. The test results show that HYSD bar-reinforced slabs have the best impact performance, with hybrid reinforcement closely following, while GFRPreinforced slabs have comparably poorer performance. Steel Fibres further enhance cracking resistance and also increase post-crack energy absorption amongst the types of reinforcements. Hybrid reinforcement tends to give a balanced response in terms of combining the toughness of steel and the corrosion resistance of GFRP. The test results thus demonstrate the potential of addition of Fibres and hybridization strategies to improve the impact performance of concrete slabs under low-velocity impact loading conditions.
A few researchers have explored the influence of reinforcement detailing and slab parameters on impact performance. Yue Wang et al. (2021) and Senthil et al. (2024) found that the peak impact force and displacement and mode of failure were significantly controlled by the thickness of the slab and the location of impact, while an increase in reinforcement ratio alone allows only limited improvement because the damage mechanism is dominated by concrete. Reinforcement spacing has been experimentally and numerically studied by Tolga Yılmaz et al. (2019), who demonstrated that closer spacing of the bar effectively restricts deflection and propagation of cracks under dropweight impact loading. With the purpose of enhancing impact resistance, steel fibre reinforced concrete has gained significant attention. Experimental works by Tekleab and Wondimu (2022) and Vivas et al. (2020) showed that steel fibres enhance crack control, toughness, post-cracking energy absorption, and reduction of spalling and punching damage. Similarly, Reddy et al. (2024) pointed out the synergistic effect resulting from hybrid fibre systems, which exhibited high mechanical properties improvement and outstanding impact resistance when compared to plain concrete. Over the last couple of decades, there has been interest in non-corrosive reinforcement as an alternative to traditional steel reinforcement. Experimental and numerical studies conducted by Maher A. Adam et al. (2021) and Hamid Sadraie et al. (2019) demonstrated that GFRP-reinforced slabs develop larger deflections and more dispersed cracking under impact, attributed to the lower elastic modulus of GFRP. However, adequate impact resistance may be achieved by adopting an appropriate reinforcement configuration. Further numerical studies by Liu Jin et al. (2023) have demonstrated that during impact, concrete absorbs most of the energy, while GFRP reinforcement contributes insignificantly to energy dissipation but rather to postimpact integrity.
Key Words: Steel Fibre Reinforced Concrete (SFRC), Glass Fibre Reinforced Polymer (GFRP), impact loading, residual strength, energy absorption, crack propagation, bond degradation, impact resistance.
1. INTRODUCTION Concrete slabs in civil and industrial structures are often subjected to low-velocity impact load arising from falling objects, vehicular movements, industrial accidents, and extreme events. Such loading results in highly localized damage, degradation in stiffness properties, and progressive cracking, and is not sufficiently elicited through conventional static design procedures. Hence, a large number of experiments have been conducted and numerical
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Hybrid reinforcement systems are being presented to combine the advantages of steel and GFRP reinforcement. Tohid Mousavi and Erfan Shafei demonstrated in 2019 that
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