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Reinforced composite materials
Published in Andrew Livesey, Motorcycle Engineering, 2021
Aramid fiber is a manmade organic polymer, an aromatic polyamide, produced by spinning fiber from a liquid chemical blend. The bright golden yellow fibers have high strength and low density, giving a high specific strength. Aramid has good impact resistance. Aramid is better known by its Dupont trade name: Kevlar.
Reinforced composite materials
Published in Andrew Livesey, Bicycle Engineering and Technology, 2020
Aramid fibre is a man-made organic polymer, an aromatic polyamide, produced by spinning fibre from a liquid chemical blend. The bright golden yellow fibres have high strength and low density giving a high specific strength. Aramid has good impact resistance. Aramid is better known by its Dupont trade name Kevlar.
Textile fibres
Published in Michael Hann, Textile Design, 2020
Aramid fibres are synthetic fibres, characterised by the potential for high performance with respect to low weight, strength and resistance to heat. Known commonly by the DuPont brand name, Kevlar, categories of these fibres were used commonly as reinforcing components in composites, as well as for applications in aerospace, ballistics, military and sports areas. They have functioned as the main component in protective clothing where they have offered protection against heat and chemicals.
State of art review on the incorporation of fibres in asphalt pavements
Published in Road Materials and Pavement Design, 2023
Shenghua Wu, Ara Haji, Ian Adkins
Aramid fibres are a class of extremely resilient and heat-resistant synthetic fibres, belonging to the group of aromatic polyamides (Wiśniewski et al., 2020). The fibre-forming substance is a long-chain synthetic polyamide in which at least 85% of the amide linkages are attached directly to two aromatic rings. The fibre is produced by spinning a solid fibre from a liquid chemical blend. Aramid fibres are rather expensive and difficult to manufacture, but unlike high molecular weight polyolefin fibres, aramids have a polar aromatic polymer backbone, which results in a much higher glass transition temperature and no melting point. Due to the aromatic structure, aramid fibres have excellent heat resistance, very low flammability and good chemical resistance to most organic solvents, but are sensitive to salt (chlorine), and to some acids and bases, as well as to degradation from ultraviolet radiation.
Flexural behavior of high-performance and non-high-performance textile reinforced concrete composites
Published in European Journal of Environmental and Civil Engineering, 2023
Mojdeh Zargaran, Nader K. A. Attari, Saeid Alizadeh
Load-deflection curves of samples strengthened with 1, 2, 4 and 8 layers of fabric 3 are presented in Figure 8. Aramid is a high-performance roving, and the area below the load-displacement diagram of flexural response of samples strengthened with Aramid fabric indicates a great toughness and energy absorption capacity. The drop in bending moment after the first peak is less than the samples reinforced with PP fabrics, which is due to the high elastic modulus of Aramid roving (second modulus), and as the number of layers increased in the composite, the enhancement in flexural strength was observed. Strain hardening behaviour is visible in samples with 2, 4 and 8 layers of fabric 3. The ductility behaviour of fabric 3 samples is provided in Table 5. The ductility of 4- and 8-layer composites were about 14 and 24.2 times more than plain concrete and loads sustained were 3.36 and 4.6 times more than plain concrete respectively.
Effect of synthetic fibres on fracture performance of asphalt mortar
Published in Road Materials and Pavement Design, 2020
Panos Apostolidis, Xueyan Liu, Gerald C. Daniel, Sandra Erkens, Tom Scarpas
Looking at the chemical structure of PPD-T aramid fibre, the aromatic ring structure contributes to high thermal stability, while the para configuration contributes to the increase of modulus (Jassal & Ghosh, 2002). Aramid has higher mechanical properties than other polymer fibres while maintaining the same weight as glass or steel fibre, even at high temperatures, as its melting point is no less than 400°C. These enable a broad range of aramid fibre applications, particularly in hostile environments. In general, aramid fibres behave elastically when subjected to tension (van der Zwaag, 2009). However, different behaviour is shown under compression or bending, as plastic deformation occurs. This phenomenon is known to correspond to the formation of structural defects named as Kink bands related to compressive buckling of the aramid molecules. Therefore, the use of aramid as reinforcement in a compressive structure should be allowed only to a limited value.