Strength and Flexural Toughness of Concrete Reinforced with Steel-Polypropylene Hybrid Fibres

Results of an investigation conducted to evaluate the strength and flexure toughness ofHybrid Fibre Reinforced Concrete (HyFRC) containing different combinations of steel andpolypropylene fibres are presented. An experimental programme was planned in whichbeam specimens of size 100 x 100 x 500 mm were tested under four point static flexuralloading to obtain the flexural strength of HyFRC. In addition, cube specimens of size150 x 150 x 150 mm were also tested to obtain its compressive strength. The specimensincorporated steel and polypropylene fibres in the mix proportions of 100-0%, 75-25%,50-50%, 25-75% and 0-100% by volume at a total volume fraction of 1.0%. The flexuraltoughness parameters were obtained using procedure laid down in ASTM C-1018 C, JCIMethod, ASTM 1609/C 1609 M and Post Crack Strength (PCS) Method. The results indicate that concrete containing a fibre combination of 75% steel fibres + 25% polypropylene fibres can be adjudged as the most appropriate combination to be employed in HyFRC for compressive strength, flexural strength and flexural toughness.