Microstructure, electrical and mechanical properties of steel fibres reinforced cement mortars with partial metakaolin and limestone addition

This paper investigates binary and ternary binders of ordinary Portland cement, metakaolin and limestone as a possible solution to reduce the amount of cement content in mortar mixes. Furthermore, the mortar mixtures were reinforced with steel fibres and their properties were investigated. The effectiveness of metakaolin and limestone on compressive and flexural strength of mortar samples as mechanical properties was analysed. Results indicated that partial substitution of metakaolin in mortar mixtures provides higher compressive strength values at early ages; combined mixtures of limestone and metakaolin enhanced compressive strength comparing with 100% ordinary Portland cement (OPC) as the binder. Flexural strength values improved by increasing the number of steel fibres in mixtures; variations in metakaolin and limestone on mixtures seemed not to affect on final flexural results significantly. Electrical resistivity results revealed substantial improvements on the likelihood corrosion and corrosion rate of mortar mixtures. The addition of steel fibres to the admixture significantly decreased the ER mainly due to the conductivity of the fibres.