**3. Types of fibres**

There are numerous fibre types, in various sizes and shapes, available for commercial and experimental use. The basic fibre types are steel fibre; synthetic fibres, such as polypropylene, glass, carbon, polyolefin and polyvinyl; and waste fibre materials. Using these fibres individually as well as on hybrid basis has an effect on the mechanical properties of FRC members. These mechanical properties depend on the type, geometry, and content of fibres [2, 3] as

The addition of fibres into cementitious composites enables considerable improvement in mechanical and dynamic properties of reinforced concrete members. The delay and control of tensile cracking in the composite material are the most considerable outcome of fibre associated with concrete [4]. Most mechanical properties of composite are enhanced using intercept micro-cracks. ACIFC [5] stated the reliance of the level of enhancement accomplished on the type of fibre and the dosage rate as compared to plain concrete. Thus, FRC demonstrates excellent tensile strength, toughness and energy dissipation capacity [6, 7]. It also increases significantly the shear [8–10], flexural [9, 11, 12], punching [13, 14], resistance and durability ([15, 16]; Kunieda et al., 2014) of concrete structures as well as superb resistance to cracking [17].

Those attractive properties allow the direct application of fibres in concrete. However, each fibre type could enhance specific concrete properties. Accordingly, the aim of this chapter is to investigate into the potential of using various types of fibres which include steel fibre and synthetic fibres such as polypropylene, glass, carbon, polyolefin and polyvinyl in enhancing

Recent researches have shown that waste fibres can also be a valuable reinforcement system to decrease significantly the brittle behaviour of cement-based materials, by improving their toughness and post-cracking resistance [18]. It also has beneficial environmental and economic impacts [19, 20]. The effect of using waste fibre in enhancing concrete properties is also reported. The use of two or more types of fibres in a suitable combination showed a great potential to optimise the properties of concrete material as well as to improve the mechanical performance of reinforced concrete members. This combining of fibres, often called hybridization is currently used as the inclusion of single fibre in concrete cannot attain an optimal performance. The use of hybrid is commonly limited to two types. These are a mix of steel and polypropylene fibres and a mix of steel fibres with different geometry, shape and size. A further description on different fibre combinations is shown in the below sections. This chapter reported on the historical use of fibres; types of fibres; the addition, mixing, placing, finishing and curing of steel, polypropylene and structural synthetic fibres and the mechanical properties of cement-based composites rein-

forced with steel, polypropylene, structural synthetic, water fibres and hybrid fibres.

gated within the 1960s and 70s due to health issues related to asbestos fibres.

Fibres were used at least 3500 years ago to build the 57 m high hill of Aqar Quf near Baghdad through brittle matrix materials and sun-baked bricks [21]. Additionally, masonry mortar and plaster were reinforced through horsehair [22]. Similarly, cement products were reinforced through asbestos fibres for about 100 years ago. In contrast, alternate fibre types were insti-

described below.

32 Cement Based Materials

the mechanical properties of concrete.

**2. Fibres: origin and history**

Fibre types are accessible for experimental and commercial use in assorted sizes and shapes. The basic fibre categories are steel fibre; synthetic fibres, such as polypropylene, glass, carbon, polyolefin and polyvinyl; and waste fibre materials. However, in structural cement-based elements, steel, polypropylene and structural synthetic fibre reinforced concrete as well as waste fibres are the main types of fibre, which are used as a replacement for conventional steel fabric reinforcement. Using these fibres individually as well as on hybrid basis has an effect on the mechanical properties of FRC members. These mechanical properties depend on the type, geometry and content of fibres [2, 3] as described below.
