Evaluating resistance of microsilica and colloidal nanosilica in Indian ordinary Portland cement mortar against combined chloride and sulfate attack

This study enhances the durability of mortar blends against the combination of chloride and sulfate attack by replacing the certain quantity of Portland cement with microsilica and colloidal nanosilica. Coastal surroundings have severe chloride and sulfate ion precipitation. To establish concrete durability under these environments it is essential to incorporate both ions. Investigation of microsilica and colloidal nanosilica in concrete has been acknowledged in recent times. Moreover, the role of durability mortar combined with microsilica and colloidal nanosilica (CNS) have also been limited. A preliminary tool is conducted to establish five different chlorides and sulfate corrosive solutions to evaluate various replacement percentages of microsilica and colloidal nanosilica content in cement. In binary and ternary solutions, the necessary properties such as mechanical, electrical, change in mass, expansion, permeability and surface morphology were studied. Results revealed that colloidal nanosilica as a partial substitution improved mortar property, enhanced mortar durability and less deterioration in ordinary Portland cement (OPC) specimens and the chloride penetration developed by inserting sulfate ions at an early immersion age.