Strength and flexural toughness of steel fibre reinforced concrete

Abstract

It is known that concrete is relatively a brittle material and has serious short-coming of poor toughness. Addition of randomly distributed fibres improves concrete structural characteristics viz. static flexural strength, ductility and flexural toughness etc., which depend upon fibre type, size, aspect ratio and volume fractions of the fibres used. Fibres are added to concrete to improve energy absorption and apparent ductility. Flexural toughness, derived from the load-deflection response, is often used to describe these improvements. There are however, a number of uncertainties regarding how fibre reinforced concrete flexural toughness should be measured interpreted or used. In the present investigation mechanical properties such as compressive strength, splitting tensile strength and flexural strength were compared for concrete containing different combinations of rectangular corrugated and both end hooked steel fibres at a fibre volume fraction of 1.0% and 1.5%. Flexural toughness results of all mix combinations as measured by toughness indices using ASTM C1018 method are also presented. The results indicate that concrete containing a fibre combination of 50% corrugated steel fibres + 50% both end hooked steel fibres at 1.5% volume fraction can be adjudged as the most appropriate combination to be employed in steel fibre reinforced concrete for compressive strength, flexural strength and flexural toughness.