High-compressibility, low-shear-strength soils are notoriously difficult to engineer on, so traditional chemical stabilising additives like cement and lime have been used extensively to improve their engineering qualities. Soil stabilisation methods, both chemical and mechanical, are employed to improve the material's engineering properties. There is a growing need for more environmentally friendly and long-lasting materials in construction and landscaping, which could have a profound effect on the field of soil improvement around the world. Recent research shows that geopolymers and biopolymers can be used to stabilise bentonite clay, improving its engineering properties in a sustainable way. © 2024 Elsevier B.V., All rights reserved.