Review of Fly-Ash-Based Geopolymers for Soil Stabilisation with Special Reference to Clay

Alkali-activated binders, more commonly referred to as “geopolymers”, have recently emerged as a good alternative to traditional binders (e.g., lime and cement) for soil stabilisation. Geopolymers utilise the alkaline activation of industrial waste to form cementitious products within treated soils, leading to enhanced soil properties. This paper aims to present a review of the use of fly-ash-based geopolymers for soil stabilisation, with special reference to clay. The paper provides some detailed chemical and geotechnical cross-disciplinary knowledge, which advances fly-ash geopolymer as an eco-friendly binder. The paper covers the salient features of the geopolymer treatment process, including key affecting factors, envisioned applications, potential advantages and major limitations. The paper also discusses the main challenges standing against the wide recognition of this technique for soil stabilisation by industry. The paper finally concludes that fly-ash geopolymer can be used successfully as a binder for soil stabilisation; however, further research is still needed to realise the full potential of this promising technique in the future.