Mechanical properties and durability of ternary blended cement paste containing rice husk ash and nano silica

•Strength and durability assessment of cement paste.•Cement paste using Rice husk Ash and Nano silica.•Effect of Rice husk Ash and Nano silica in cement paste based on compressive strength, flexural strength, Ultra pulse velocity (UPV) test, water absorption test, Acid attack test and X-Ray diffraction (XRD) analysis. Many researchers are using Rice husk ash (RHA) as pozzolanic admixture. Pozzolanic admixture is an amorphous aluminosilicate materials, which may not be naturally cementitious, but react with calcium hydroxide (Ca(OH)2) and water to form cementitious compounds. Further, many researchers also found that the use of Nano silica (NS) in Portland cement (PC) enhances the mechanical properties as well as durability. The present study reports on the addition of RHA and NS into PC, aiming to assess the influence of the RHA and NS on the strength and durability properties of mixture. The pastes were prepared to perform compressive strength test, Flexural strength test, Ultra Pulse Velocity (UPV) test, Water absorption test, Acid attack test and XRD analysis. Compressive strength results showed a substantial improvement in samples containing NS. The highest compressive strength and flexural strength are found in the PC-based mixture containing RHA (10%) and NS (3%) after 28 days of hydration. PC-based mixture containing RHA (10%) and NS (3%) shows reduction of water absorption and mass loss under acid attack at 28 days. It is also seen that a combination of 10% RHA and 3% NS in paste led to a positive contribution to durability properties. Synergistic effect can be seen in mixtures incorporating RHA (10%) and NS (3%). Therefore, it supports the use in fabrication of cementitious materials.