Pullout behaviour of hooked end steel fibres embedded in concrete with various cement replacement materials

The purpose of this study is to investigate the mechanical behaviour of concrete reinforced by high tensile strength steel fibres and the physical and mechanical effects of cement replacement materials on the fibre-matrix bond. The cement replacements which have been used in this research included silica fume, pulverised fuel ash, limestone filler and ground granulated blast-furnace slag. In total, more than 700 samples have been manufactured for experimental research on compressive strength and pullout behaviour of hooked end steel fibres from cement based matrices. The effects of parameters such as water/binder ratio, cement replacement content, age of sample, hooked end shape and tensile strength of fibre on fibre–matrix pullout behaviour were determined. The results of tests and analysis indicate that hook shape and tensile strength of fibre affect the peak pullout force and ground granulated blast-furnace slag can significantly improve the pullout energy which would be useful for the optimisation of steel fibre reinforced concrete. The outcome of this research may be useful to widen the potential applications of the material across civil engineering.