specimens observed by 20.31% for the mix having steel-nylon

specimens of 100 mm and three prismatic specimens of 10 × 10 × 50 cm3, for each batch of concrete, were casted in order to evaluate respectively, the compressive strength and the flexure strength. A notch of 10 mm deep and 3 mm wide was cut in the center of each prismatic specimen using a diamond saw to localize the crack. It was concluded that :

·         Compressive strength can be maintained constant, with a relative dosage of 10% of silica fume by weight of cement , replaced by a 20% dosage of blast furnace slag.

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·         The presence of steel fibres increases the compressive strength of about 30% for a fibres volume fraction of 2% with blast furnace slag.

·         With a 2% volume fraction of fibres, the flexural strength was increased by respectively 49% and 53% for silica fume and slag-based compositions.

·         With a fibres volume fraction of 2%, the energy absorbed by the specimens during the tests was 33 times higher than the flexural toughness of plain concrete. Such an observation shall be very interesting for designing earthquake-resistant applications.

Kumar et al. (2014), for compression test 30 cubes of size 15 cm × 15 cm × 15 cm for 7 & 28 days, for split tension test 30 cylindrical specimen of dimension 15 cm diameter and 30 cm length, for flexure test 30 beams of size 50 cm × 10 cm × 10 cm were casted. The four different mix combinations of steel nylon-6 fibres were 100-00%, 75-25%, 50-50%, 25-75%. Super plasticizer was used in all mixes to make concrete more workable. The work was concluded that:

·         Slump decreases with adding fibre in concrete. Maximum slump loss was obtained for mix steel-nylon fibre having 50-50% by volume of concrete.

·         The maximum compressive strength obtained from mix having steel fibre only.

·         Maximum increase in split tensile strength is by 20.84% for mix having steel- nylon 100-0%.

·         Maximum increment of flexural strength is observed by 20.31% for the mix having steel-nylon fibre 75-25%.

Qureshi et al. (2013), evaluated the effect of cocktail fibres (mixture of steel fibres and poly propylene fibres) on reinforced concrete. Comparison was carried out by preparing and testing 30 specimens of plain & reinforced concrete incorporating different ratios of fibres. Monofilament polypropylene fibres and undulated steel fibres were used in various dosages and their effect on the cracking strength in terms of compressive strength as well as ultimate load capacity was observed. It was concluded that: