Analysis and optimisation of the rheology–strength relationship of basalt-fibre-reinforced self-compacting mortar

The aim of this work was to find the optimum rheology for maximising the strength of basalt-fibre-reinforced self-compacting mortar (BFRSCM). An experiment was employed to design mixes based on the basalt fibre volume percentage (F), water/binder ratio (w/b) and superplasticiser (SP) dosage. Using an L9 Taguchi array, nine mixes were designed considering combinations of F (0.5, 1.0 and 1.5%), w/b (0.35, 0.40 and 0.45) and SP dosage (D_SP) (16, 19 and 22 ml/kg). Mini slump flow diameter (SFD) and mini V-funnel time (T_v) were measured to determine the rheological characteristics and compressive strength (CS) and split tensile strength (STS) were conducted to determine the mechanical properties of the BFRSCM mixes. After statistical analyses, optimisation and prediction, rheology–strength relationships and optimum properties were ascertained. For further assessment of microstructures, scanning electron microscopy was conducted on three different mixes. It was found that the optimum combinations of (F, w/b, D_SP) for CS and STS were (1.0%, 0.35, 19 ml/kg) and (1.5%, 0.40, 16 ml/kg), respectively. The optimum fibre percentage for CS was F = 1.0%, while for STS it was F = 1.5%. The optimum rheology for maximum CS occurred with SFD = 27.5 cm and T_v = 7.9 s, while that for maximum STS was with SFD = 29 cm and T_v = 5.0 s. The mean absolute percentage errors of the predictions for all properties were lower than 5% except for T_v, which was 13%.