STUDY OF COMPRESSIVE AND FLEXURAL STRENGTH OF FIBROUS TRIPLE BLENDED HIGH STRENGTH CONCRETE WITH FLY ASH AND CONDENSED SILICA FUME

Abstract

Concrete is the most widely used Civil Engineering material employed for the construction of various types of structures in the world. Continuous research has been carried out in the area of concrete technology to improve the quality of concrete and to make it suitable for different purposes. As a result, many forms of concrete like High strength concrete (HSC), High performance concrete (HPC), Fibre reinforced concrete (FRC), self-compacting concrete (SCC) have been developed. Mineral admixtures like flyash, condensed silica fume(CSF), ground granulated blast furnace slag (GGBS) etc are being tried as part replacement cement to impart additional properties and benefits. Metallic fibres like steel when mixed at certain percentages in concrete, generate higher strength particularly in tension and flexure besides preventing micro cracks. In the present experimental investigations, triple-blending of ordinary portland cement (OPC) and two mineral admixtures, flyash and CSF are blended together to develop triple blended concrete mix. M80 design mix of concrete is taken as reference. The percentages of flyash and CSF are varied. Various percentages of steel fibres like 0, 0.5 and 1.0 are employed in various mixes. Thus, various combinations of triple blended fibrous concrete mixes of high strength are developed. Tests were conducted on samples of triple blended fibrous high strength concrete mixes for compression and flexure. The results have indicated that triple blending has helped concrete in respect of using lesser cement, without sacrificing the strength. Fibres have helped to improve the tensile and flexural strengths of concrete in addition to preventing micro cracks and improving the ductility property. The triple blended fibrous high strength concrete has optimum properties in all the respects.