Optimum mechanical properties of repair mortar containing hybrid fibers using the Taguchi method and analysis of variance

In this study, a hybrid fiber containing micro steel fiber (MSF), polyester fiber (PEF) and glass fiber (GF) was employed to improve a hardened properties of repair mortar. The design of experiments for the repair mortar was based on Taguchi method and included hybrid fiber-MSF, PEF and GF- at three levels, along with additional parameters such as the binder-to-sand ratio, silica fume (SF) content, latex content and the water-to-binder ratio at different levels. The compressive strength, flexural strength, and shear bond strength were determined to study the effect of the hybrid fibres on the properties of repair mortar. The results of experimental tests were optimized through the analysis of variance (ANOVA). The findings indicated that hybridization of 1.0%MSF +0.25%PEF +0.25%GF as the optimal combination significantly improved the compressive strength and also enhanced the flexural and shear bond strength of the repair mortar.