Impact of nano-silica on the mechanical properties of lightweight concrete

Abstract

Recent research has shown that lightweight concrete (LWC) offers a series of advantages, leading to a noteworthy evolution in this field. Numerous high-performance features are offered by nanomaterials added to LWC. This study examines the impact of nano-silica (NS) at concentrations of 1 %, 3 %, 5 %, 10 %, 15 %, and 20 % on the properties of LWC both fresh and hardened. Slump tests were used to estimate the workability of all mixes. To assess for toughened qualities, tests for density, compressive strength, and microstructure were employed. In comparison to the reference mixture, the application of NS improved the microstructure and total compressive strength. The percentage of NS at 5 % with a 90-day increase the compressive strength by 77 %. The microstructure analyses demonstrate that the hydration process of the cement paste can be changed with the addition of nano-silica, and new types of hydration products have been observed in nano-modified cementitious matrix. The interface between the lightweight aggregates and the cement paste can be reinforced by nano-silica due to the new types of hydration products.