Investigative Study on Hybrid Fiber Reinforced Concrete using a Combination of Steel and Polypropylene (PP) Fibers

Abstract

The objective of the current project is to conduct an investigative study of the high-strength hybrid fibre reinforced concrete, i.e., the mixture of steel and polypropylene fibres. The compressive strength and a flexural strength of hybrid fibre-reinforced concrete with various percentages of fibres were tested using M30 grade concrete. Normal concrete of M30 grade was taken as the control specimen. The specimens of hybrid fibre-reinforced concrete cubes and flexural beam were casted with a different proportion of the fibres, i.e., with 0.0, 1.0, 2.0, per cent fibre contents. Specimens are put to test on compression, and flexural strength. Physical and chemical properties of the two steel fibres and the polypropylene fibres were examined. A concrete mixture was prepared to achieve the grade of M30 needed in IS 10262-2019. The investigation was done in two phases. The first stage is research and the identification of the Physical characteristics of the fiber materials. Concrete specimen containing 1% of steel fiber and 0.30% of polypropylene fiber were tested under the various aggressive environment including air, water, sodium chloride over the duration of 28 days. The results demonstrated significant improvement in compressive strength, tensile and flexural strength. And the second stage contains the mix proportions of 2% of steel fibers and 0.30% of the Polypropylene fibers that gives absolutely high strength in the duration period of 7 days, 14 days and 28 days. The improvement in the toughness, crack resistance and better resistance to chloride penetration and chemical attack. The synergy between Steel and polypropylene fibers improved resistance to RCPT and reduced Permeability range and exhibits the best performance and contributing to enhanced long-term durability. These findings give the Hybrid fiber reinforced concrete can be substantially extend the service life of structure exposed to harsh environment by simultaneously improving mechanical properties and durability.