A review on the Choice of Nano-Silica as Soil Stabilizer

Soil stabilization using nano-additives is one of the trending developments of the decade. Many novel nano-stabilizers were tested by researchers for ground improvement applications. However, the capability of such materials in soil stabilization needs further detailed practical investigations beyond the controlled research environment. On the other hand, many well-proven nano-based stabilizers have constraints like availability, cost, difficulty in implementation method, and the practical feasibility of such usages. Among many well-established additives, nano-silica is one such material that was under research for over a decade and showed promising results for use as a soil stabilizer. Hence, the present work proposes a comprehensive review on characteristics of nano-silica, including its physical nature; its influence on curing methods and ageing, its behavior upon adding with soil and other additive materials in terms of strength improvement, hydraulic conductivity and compressibility; reaction mechanism in various soil and additives and a discussion on the gaps that need to be addressed to transfer this technology to field practices. Literature studies indicate that nano-silica as a sole-additive improved the soil strength and it acted as a strength enhancer for cement, lime and fiber treated soils. Also, nano-silica helps in reducing hydraulic conductivity and compression index of the soil. Further, an analysis on the minimum strength improvement with nano-silica on various types of soils is discussed based on the reported literature. With promising results from the review, further advancements on eco-friendly and cost-effective biogenic production methods would establish nano-silica as a competitive additive in the field of geotechnical engineering.