Compressive and tensile behaviour of alkali‐activated slag‐based concrete incorporating single hooked‐end steel fibres

The effect of single hooked‐end steel fibres, namely Dramix^® 3D, on the mechanical performance of alkali‐activated slag‐based concrete (AASC) and Portland cement concrete (PCC) has been investigated. Compressive strength, modulus of elasticity, stress‐strain response under uniaxial compression and tension, splitting tensile strength and flexural strength have been evaluated. The experimental results show that AASC incorporating 3D fibres in a volume fraction of 0.75% exhibits an enhanced behaviour, under both compression and tension, in comparison to PCC incorporating the same fibre type and dosage. Although the reference mixes show similar compressive strength, 3D fibres enhance the modulus of elasticity, splitting tensile strength and flexural strength of AASC of 8.6%, 61.7% and 12.8%, respectively, while for PCC 1.1%, 42.2% and 16.1%, respectively. Three‐point bending tests show the effect of 3D fibres on the response of AASC and PCC under flexural loading. Although fibres have a limited effect on the strength corresponding to the limit of proportionality (LOP), they enhance the post‐peak behaviour, increasing the residual flexural strength and the material ductility. Finite element analysis has been performed to predict the flexural behaviour of steel fibre‐reinforced AASC (FRAASC) under flexural loading. The Concrete Damage Plasticity (CDP) model implemented in ABAQUS software can predict the flexural response of FRAASC quite accurately, although additional experimental data are needed to calibrate the model for different alkali‐activated matrix types.