Microbially induced carbonate precipitation (MICP) for soil strengthening: A comprehensive review

Geotechnical research has been yearning for revolutionary innovations that could bring breakthroughs to conventional practices, especially at a time when energy efficiency and environmental sustainability are of unprecedented importance in the field. Recently, exciting opportunities emerged utilising microorganisms, the ubiquitous soil dwellers, to provide solutions to many geotechnical problems, prompting the development of the new, multidisciplinary subject of biogeotechnics. Research interest has been centred on the use of microbially induced carbonate precipitation (MICP) to improve the engineering properties of soils. The present work aims to comprehensively review the progress of more than a decade of research on the application of MICP in soil strengthening. Through elucidation of underlying mechanisms, compilation and interpretation of experimental findings, and in-depth discussion on pivotal aspects, with reference made to key published studies, a holistic picture of the state of the art of MICP-based soil strengthening is drawn. Current knowledge gaps are identified, and suggestions for future research are given, along with the opportunities and challenges that lie ahead of practically implementing this technique in real-world geotechnical applications.