• G.Chandra Babu
• Dr.B.Madhusudana Reddy

: In the present investigation a detailed experimental study is carried out on hardened properties of M25 grade concrete with reinforcing steel fibre (SF) and polypropylene fibre (PPF) at various volume proportions. Initially the cube (150mmx150mmx150mm) compressive strength was tested for different proportions of steel fibre i.e. 0%, 0.75%, 1%, 1.25%, 1.5%, 1.75% and 2% of volume of the concrete. It is noticed that the optimum dosage of steel fibre is found to be at 1% volume proportion of concrete when tested at 28 days. The concrete mix design for M25 grade is done as per IS:10262-2009 and the proportions obtained are cement=350kg, fine aggregate=583.93kg, coarse aggregate(12.5mm & 20mm) =1235.3kg and water = 168kg. By keeping SF dosage at 1% of volume proportion constant then to it PPF is added to the concrete mix at varying volume proportions (0.3%, 0.4%, 0.5%, 0.6%, 0.7%) and different physical tests were conducted. The various properties studied with these different combinations of SF and PPF (Hybrid fibre) are Compressive strength, Split tensile strength, Modulus of elasticity and Flexural strength. Water absorption is also conducted for assessing the durability. The shape of SF used is End hooked having the aspect ratio of 50 whereas PPF is straight with aspect ratio of 1600. Based on the results obtained, it is noticed that the maximum value of strengths for the above mentioned physical tests is found at 1% SF and 0.4% PPF together. The reinforcement of hybrid fibre in the concrete doesn’t showed the considerable effect on the durability parameter.

- M25 Grade concrete, Steel fibre(SF), Polypropylene fibre(PPF) , End hooked, Compressive strength, Split tensile strength, Modulus of elasticity, Flexural strength and Durability parameter

"A Study on the hardened properties of M25 grade concrete with hybrid fibre reinforcement", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 5, page no.97-103, May-2019, Available :http://www.jetir.org/papers/JETIR1905H16.pdf

"A Study on the hardened properties of M25 grade concrete with hybrid fibre reinforcement", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 5, page no. pp97-103, May-2019, Available at : http://www.jetir.org/papers/JETIR1905H16.pdf