Mechanical properties of concrete and hollow concrete blocks containing steel and nylon fibres

Abstract

An attempt has been made in this paper to study the effect on the mechanical properties of the concrete and hollow concrete block when different types of fibres were added to the mix. The two different types of fibres added include Steel fibres with hooked end and of length 60mm at five different fibre ratios of 2.5%, 2.75%, 3.0%, 3.25% and 3.5% and Nylon fibres having a length of 18mm at the content of 0.5%, 0.75%, 1.0%, 1.25% and 1.50%. The concept of fibre hybridization was also analyzed and the effect was studied by preparing concrete mix with various percentage combinations of steel and nylon fibres at a total fibre ratio of 3% by weight of cement. The investigation focused on finding the optimum values of fibres to be added and also carried out the compressive strength and tensile strength of concrete with and without fibres. The compressive strength of hollow concrete blocks made with and without fibres was also analyzed. The samples of concrete and hollow concrete blocks were cast and immersed in water for a curing period of 28 days. The results on strength of fibre added concrete and hollow concrete block obtained was compared with the control mix result and the study concludes that the steel fibre and nylon fibre added concrete and hollow concrete block showed an improvement in the mechanical properties for each fibre ratio considered. Out of the various combinations of steel and nylon fibre tried, the best compressive strength improvement was exhibited by the concrete mix with 3% of the steel fibre without any addition of nylon fibres while the best tensile strength improvement was shown by the concrete mix with 2.25% of steel fibre and 0.75% of nylon fibre.