the energy required for fibre pull-out. The toughness increase was observed both for normal and high performance concretes, and for both types of fibres at both dosages (Pigeon et al., 1998, Rokade etal., 2014).
2.3.4 Advantage and Disadvantage of SPFRC
Fibre reinforced concrete has started to find its place in many areas of civil infrastructure applications where the need for repairing, increased durability arises. The advantages can be listed as follows:
(i) With the high performance of tensile strength, large aspect ratio uniform separation in the concrete, Steel Fibres Reinforced Concrete can bear more loads and absorb more deformation (Chang et al., 2013).
(ii) The profiles of steel fibre either hooked end or crimped ensure optimum anchorage between steel fibres and concrete, which enable the Steel fibres to transfer and distribute stress effectively. The polypropylene fibres act as tiny bridges and control the crack initiation and extension in the concrete (Qureshi et al., 2013).
(iii) Steel fibres concrete has high performance of wear ability and fatigue resistance. It is especially suitable for the project position subject to serious impact damage and high fatigue architectural structure (Girish et al., 2012).
(iv) Polypropylene fibre improves the resistance to plastic shrinkage cracking (kumar et al., 2013)
(v) Savings in material and labour cost by eliminating conventional reinforcement.
(vi) Reduced slab thickness due to higher flexural strength leads to less material usage. Thickness can be reduced (typically 20–35%).
(vii) In longer service life and less maintenance costs.
The main disadvantage associated with the fibre reinforced concrete is fabrication. The major deficiencies can be listed as follows:
(i) Polypropylene fibres are hydrophobic and therefore have the disadvantages of poor bond characteristics with cement matrix, a low melting point, high combustibility and a relatively low modulus of elasticity (Qureshi et al., 2013).
(ii) Long polypropylene fibres can prove difficult to mix due to their flexibility and tendency to wrap around the leading edges of mixer blades (IS, 2013).
(iii) Polypropylene fibres are tough but have low tensile strength and modulus of elasticity; they have a plastic stress-strain characteristic.