PSI - Issue 64

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Ali Alraie, Saverio Spadea, Vasant Matsagar/ Structural Integrity Procedia 00 (2019) 000–000

1944 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers Keywords: natural fibre; post-tensioning; sustainability; flexural performance; serviceability. Ali Alraie et al. / Procedia Structural Integrity 64 (2024) 1943–1950

1. Introduction Fibres have been used in the toughening of pottery and bricks since the very beginning of civilisation. The four main categories of fibres are metallic, glass, synthetic, and natural. From a cost perspective, plant fibres require little industrialisation, and the energy needed for their production is small. Therefore, the cost of fabricating these composites is also low. Natural fibres are renewable raw materials globally available with good mechanical properties similar to synthetic materials in the case of bast fibres. They have good heat, acoustic, and electrical insulating properties, and their various products can be disposed of by burning at the end of useful service lives so that energy can simultaneously be generated (Thiruchitrambalam et al., 2010). Even though the merits above, natural fibres have some demerits such as low strength properties, high moisture absorption tendency, low durability, and poor fire performance. Thus, there are several challenges while utilising such fibres due to a lack of standard practices and high property variation according to species, location, and ageing. Overall, using natural fibres is a more environmentally friendly alternative and contributes to sustainability compared to other types of fibres, such as steel, plastic, and glass. As a commonly used natural fibre sort, j ute is a bast fibre of low price , which comes second or just after cotton in terms of production and utilisation (Sanal and Verma, 2018). Jute fibres are made from various plant materials such as cellulose, hemicellulose, pectin, and lignin. Primarily, the jute fibre is 100% biodegradable and thus environmentally friendly, and it has high tensile strength and lesser extensibility, owing to which it is mainly used in agricultural products packaging. Besides, jute is one of the most adaptive natural fibres used in raw materials for construction and farming sectors. The primary goal of using fibres in concrete is to prevent or control the propagation of cracks in the composite. Natural fibres have been introduced to the construction industry since the late seventies. Cook et al. (1978) and Ramaswamy et al. (1983) tested short discrete fibres from coconut, jute, coir, and bamboo for incorporation in cementitious concrete. Improved ductility and remarkably lower shrinkage characteristics than plain concrete were noted as positive features of the natural fibre additions with no serious adverse effects. Recent advances in composite science, natural fibre development, and genetic engineering offer a significant opportunity for introducing innovative materials from renewable resources, positively impacting global sustainability (Mohanty et al., 2005). For instance, coconut fibre has proved to be an excellent reinforcement for polymer concrete, increasing flexural and fracture strengths (Reis, 2006), and bamboo fibres presented high durability when immersed in a cement matrix (Pacheco-Torgal and Jalali, 2011). Zhou et al. (2013) conducted experimental investigations on fracture properties of short discrete jute fibre-reinforced cementitious composites (JFRCC) with various matrixes for developing low-cost natural fibre-reinforced concrete for construction. It was noted that JFRCC had achieved higher compressive strength, splitting tensile strength, and flexural strength than plain concrete. On the other hand, coconut fibre ropes were introduced as vertical reinforcement for use in cost-effective earthquake-resistant housing (Ali and Chouw, 2013). For insulation applications, coconut coir fibre and oil palm fibre-reinforced cement sheets have relatively low heat conductivity when compared to other fibre cement sheets available in the market; therefore, these sheets can be applied as heat-insulating roofing sheets for naturally ventilated and air-conditioned residential buildings (Lertwattanaruk and Suntijitto, 2015). Alam et al. (2015a) developed high-strength natural fibre-based composite plates for the possible application in strengthening reinforced concrete structures. It was observed that RC beams strengthened with jute rope composite plates had 58% higher load-carrying capacity than the control beam (Alam et al., 2015b). Furthermore, the jute rope composite plate-strengthened beams had lesser deflection at the initial stage and higher ductility at failure than the control beam. Huang et al. (2016) investigated using natural flax fabric-reinforced polymer (FFRP) composite plates as an external strengthening material for reinforced concrete beams. They concluded that FFRP can be effectively used to retrofit and strengthen deficiently designed and damaged RC beams (e.g. after an earthquake attack). Natural