Microbiologically Induced Calcite Precipitation biocementation, green alternative for roads - is this the breakthrough? A critical review

The past fifteen years have been a rich developing field for Microbiologically Induced Calcite Precipitation (MICP) as an alternative to decrease the hydraulic conductivity of sandy soils or fractured rocks through biocementation formation. While significant development happened, the field still lacks a viable answer for the use of MICP for organic soil stabilization. Sandy soils or fractured rocks have a completely different structure and mechanical behavior than organic soils, which can impact the behavior of biological components and MICP microorganisms. This factor per se changes all the research perspective and demand adaptations different than the ones used for sandy soil or fractured rocks. In the search for answers, this article compiles an extensive and systematic literature review with papers and books from platforms like Academic Search Premier, Web of Science, Google Scholar, 1Search and Gale Virtual -Reference Library, having the selection based on defined parameters and criteria. Focusing on how MICP is a potential solution for unsealed road stabilization, this article discussed the main gaps and constraints that could explain why biocementation still needs extensive research under different perspectives and scenarios. The results suggested that the majority of investigations are at a similar stage of limitation: how to guarantee an evenly spread of biocementation into organic soil at large extensions. The discussion here provided some insights and pieces that can enrich future researches, support the expansion of the development, and improve the understanding of the biocementation process into organic soils and its use for unsealed road stabilization. (C) 2020 Elsevier Ltd. All rights reserved.