MECHANICAL PROPERTIES AND STRESS- STRAIN BEHAVIOUR OF SELF COMPACTING CONCRETE WITH AND WITHOUT GLASS FIBRES

Abstract

The development of Self Compacting Concrete marks an important milestone in improving the product quality and efficiency of the building industry. Self Compacting Concrete is a recently developed concept in which the ingredients of the concrete mix are proportioned in such a way that it can flow under its own weight to completely fill the formwork and passes through the congested reinforcement without segregation and self consolidate without any mechanical vibration. Several studies in the past have revealed the usefulness of fibres to improve the structural properties of concrete like ductility, post crack resistance, energy absorption capacity etc. Fiber reinforced self compacting concreting combines the benefits of self compacting concrete in fresh state and shows an improved performance in the hardened state due to the addition of fibers. In this investigation Cem-FIL anti-crack high dispersion glass fibres were added to self compacting concrete and Glass Fibre Reinforced Self Compacting Concrete was developed. An attempt has been made to study mechanical properties and stress-strain behaviour of self compacting concrete and glass fibre reinforced self compacting concrete. A strength based mix proportion of self compacting concrete was arrived based on Nan-Su method of mix design and the proportion was fine tuned by using Okamura’s guidelines. Five self compacting concrete mixes with different mineral admixtures like fly ash, ground granulated blast furnace slag and rice husk ash were taken for investigation with and without incorporating glass fibres. A marginal improvement in the ultimate strength was observed due to the addition of glass fibres to the self compacting concrete mix. Also incorporation of glass fibres had enhanced the ductility of self compacting concrete. Complete Stress-Strain behaviour has been presented and an empirical equation is proposed to predict the behaviour of such concrete under compression