Effect of fibres on the strength and behaviour of GPC columns

Geopolymers are alternative binders to ordinary Portland cement binder, and in geopolymer concrete (GPC) geopolymer gel is used as a binder. In the present study, the effect of steel fibres on the strength and behaviour of GPC columns under monotonic axial compression is studied. In total, 30 GPC columns with l/d ratios of 6 and 9 were cast and tested. The main variables considered in this study include different values of volume fraction of fibres such as 0·25% (19·62 kg/m³), 0·5% (39·24 kg/m³), 0·75% (58·86 kg/m³) and 1% (78·48 kg/m³) for each l/d ratio. Experimental results reveal that the addition of steel fibres slightly improves the axial strength and significantly improves the stress–strain behaviour of columns. A theoretical model for the stress–strain behaviour is proposed, and this model predicts the response of plain and fibre-reinforced GPC columns satisfactorily.