STRENGTH PROPERTIES OF HYBRID FIBRE REINFORCED CONCRETE USING FLY ASH

Concrete is strong in compression and weaker in tension. Therefore, to enhance the tensile strength of concrete certain fibres are added into the concrete. Fibre reinforced concrete (FRC) contains fibrous material, which increase the structural stability and integrity. Nowadays, hybrid fibre reinforced concrete (HFRC), which is the combination of various fibres into the conventional concrete makes it subtle and enhances the mechanical behaviour of the concrete. Aim of the study is to investigate the properties of hybrid steel and basalt fibres with and without fly ash for M25 grade of concrete. Four groups of mixtures containing fly ash (FA) contents of 0%, 10%, 20%, and 30% as cement replacement were produced with the inclusion of 0.50% steel fibres (SF) and 0.50% basalt fibres (BF) by volume of concrete. Fresh properties of mixtures were evaluated by using slump test, compaction factor and vee bee test. Hardened properties were tested at 28 days. Compressive strength, flexural strength, tensile strength, dry unit weight, porosity and water absorption were assessed. According to the results from the study, it is found that hybrid fibre reinforced concrete can act synergistically and increases the strength properties of concrete. The microcracks are checked to a larger extent. Key Words: Fly ash, Steel fibre and Basalt fibre