Effects of curing types, fly ash fineness and fibre lengths on mechanical and impact properties of steel fibre reinforced concretes

ABSTRACT This paper presents the effects of fly ash fineness, steel fibre lengths and types of curing on the compressive strength and impact strength of steel fibre reinforced concrete (SFRC). To study these behaviour, the SFRC mixtures were prepared using class-F fly ashes with specific surface areas of 2320, 3320 and 5980 cm2/g and steel fibres with lengths of 8 , 13 and 16 mm. The SFRC samples were subjected to standard wet curing, steam curing and hot water curing. The compressive strength tests were carried out after 7-, 28-, 90- and 180-day curing periods and the impact strength test was carried out after 90 days of respective curing. Results show that the workability of SFRC decreases with increase in fly ash fineness and steel fibre lengths. Results also show that the compressive strength of SFRC increase with increase in fly ash fineness and increase in length of steel fibres at all ages and all curing conditions. However, steam curing shows significant improvement in compressive strength gains of all SFRC compared to hot water curing at all ages except at 180 days. Good correlations are also observed in compressive strength with increase in steel fibre lengths at 28 and 90 days.