Stress-Strain Behaviour of Flyash Concrete With Steel Fibre

Abstract

With the ever-increasing population of the world, in general, and the developing countries, in particular, there is tremendous pressure on Civil Engineers to develop costeffective and eco-friendly structures to fulfill the needs of the mankind. Within current practices of utilisation, cement and concrete construction industries throughout the world has been the largest user of flyash, an industrial by-product, whose use and production have increased many fold during last three decades and have exploited it to the best advantage. Flyash nowadays is a four fold issue : reduction in air/water pollution, beneficial conversion of waste into wealth, reduction in expenditure on disposal and augmenting the demand of much needed construction materials which is economical and sound. Fibres on other hand have provided to improve strength, stiffness and ductility of reinforced concrete members with their addition. They act as crack arrestors, change all modes of failure, and increase ultimate strain of the composite. Experimental investigation has been carried out to study the effect of the flyash content and steel fibres on the properties of both fresh and hardened concrete. Cement has been replaced by mass with 15,20 and 25 per cent flyash content. Three percentages of steel fibres (0.25, 0.50 and 0.75 per cent) of aspect ratio 100, have been used in the investigation. Tests have been performed for Slump, Vee-Bee Time, Compressive Strength and Compressive Stress-Strain. Test results indicate that the Slump increases and Vee-Bee time decreases as the flyash percentage increases, whereas steel fibres decreases the slump and increase the Vee-Bee time sharply. The addition of steel fibres increases the compressive strength of concrete. The compressive strain of concrete increases with the increase in the percentages of fly ash. The addition of steel fibres doesn’t significantly affect the modules of elasticity of fly ash concrete.