**1. Introduction**

Advancements in cement-based technology, such as concrete technology, have led to the development of fibre reinforced concrete (FRC) materials [1]. Considerable research efforts have been made contributing to theoretical and technological knowledge about properties and behaviour of FRC across the globe. Applications of FRC are very common in civil and structural engineering.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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 described below.

In the nineteenth century, the use of reinforcing rods in the tensile zone of the concrete was imposed for the low tensile strength and brittle character of concrete [23]. In addition, the incorporation of discontinuous steel reinforcing elements including metal chips, nails and

Fibre Reinforced Cement Composites http://dx.doi.org/10.5772/intechopen.75102 33

Romualdi and Baston [24] have investigated the steel fibres potential for steel reinforcing rods in concrete during the early 1960s in the United States. Afterwards, steel fibre reinforced concrete has been advanced through assorted experimentation, industrial application and research development. Similarly, Goldfein [25] conducted experiments with and without reinforcement using plastic fibres in concrete. Structural synthetic fibres were used explicitly by Japanese construction companies since 1997 as an alternate of steel fibre reinforcement. The expansion of structural synthetic fibres is attempted in Europe, North America and Australia. Most applications suggest the use of fibre reinforced concrete such as refractory materials,

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,

Many efforts have been made in recent years to optimise the shape of steel fibres to achieve improved fibre-matrix bond characteristics, and to enhance fibre dispersibility in the concrete mix [26]. The classification for four general types is provided by ASTM A 820 on the basis of manufacturing products [22]. These products include cut sheet, melt extracted, cold-drawn

**Figure 1** has shown other common types of steel fibres. By cutting and chopping wire, rounded and straight steel fibres, having a diameter between 0.25 and 1.0mm are produced. Furthermore, shearing sheet of flattening wire produces flat and straight steel fibres of 0.15–0.41 mm thickness by 0.25–1.14 mm width. The production of crimped and deformed steel fibres is based on the full-length crimpling or bent or enlarged at each side of the fibres. The bending or flattening

The handling and mixing process is facilitated through fibres being collated into bundles. The bundles are distributed into single fibres during the mixing process. Similarly, cold-drawn wire is used to produce fibres that are smooth for making steel wool. In addition, the melt

process is used to deform fibres to expand bond and allow mixing and handling [28].

wire segments into concrete was attempted through patents recently.

concrete products, and road and floor slabs over the past 40 years [23].

geometry and content of fibres [2, 3] as described below.

extraction process is used to produce steel fibres [22].

**3. Types of fibres**

**3.1. Steel fibres**

wire and other fibres.

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 the mechanical properties of concrete.

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