Strength and Durability Assessment of Self-Compacting Concrete with Nano Silica and Metakaolin

Abstract

Self-compacting concrete (SCC) has become some of the sophisticated construction materials due to its enhanced flowability, ability to self-compact, and capacity to form dense and homogenous concrete without mechanical vibration. Improving its mechanical strength and overall durability and facilitating sustainable construction is one of the major research areas. This paper explores the synergy of nano silica and metakaolin as an addition to cementitious materials in enhancing the strength and longevity of SCC. Various replacement amounts of nano silica and metakaolin were added to concrete mixtures and tested based on testing standards. The experimental program involved fresh concrete characterization on slump flow, T50 flow time, V-funnel and L-box tests followed by measurement of compressive strength at 7, 28 and 56 days. The performance of durability was measured in terms of water absorption and Rapid Chloride Penetration Test (RCPT). It was found that the use of nano silica and metakaolin enhances the hydration process, refines the pore structure and strengthens the interfacial transition zone, which results in high compressive strength and resistance to moisture and chloride diffusion. The ideal mix of replacement gave the most appropriate balance between workability, mechanical performance and durability. As revealed in the study, a synergistic approach of using nano silica and metakaolin is a viable approach towards application of high performance, durable and sustainable self-compacting concrete to be used in modern infrastructure.