Strength and permeation properties of self-compacting concrete containing fly ash and hooked steel fibres

Abstract

This paper presents properties of self-compacting concrete (SCC) made with class F fly ash and hooked steel fibres. The effect of steel fibres (0.5%, 1.0% and 1.5% by volume) on rheological (slump flow, V-funnel, L-box, U-box), strength (compressive strength, splitting tensile strength and flexural strength) and permeation properties (porosity, rapid chloride permeability, ultra sonic pulse velocity) of SCC specimens, were investigated.The results indicated that the workability of SCC with 0.5% and 1.0% hooked steel fibres by volume, are found in range set by EFNARC and get reduced to some extent with increase in fibres volume fractions up to 1.5%. This led to decrease of other rheological characteristics prescribed by EFNARC and ACI 237 R. The enhancement in properties of SCC is because of augmentation in interfacial or bond strength of steel fibres and pore refinement by fly ash. In contrast, the improvement in properties of concrete like compressive strength from 34.6 to 38.5N/mm2, splitting tensile strength from 3.8 to 6.2N/mm2 and flexural strength from 5.5 to 8.2N/mm2 at 28days was observed with increase in fibres content. SCC mixes with steel fibres exhibited very low range charge passing (100–1000Coulomb) in rapid chloride ion penetrability, porosity increased from 9.3% to 9.9% and decrease in ultra sonic pulse velocity of about 17% at 28days were observed with increase of steel fibre contents by volume in SCC mixes.