Microfluidic-Based Study on the Activation and Evolution of Calcite Bio-Mineralization for Geotechnical Applications

The field of geotechnics is moving fast towards benefiting from new methods and tools to improve the understanding of couplings among complex transport, chemical and biological phenomena. Calcite bio-mineralization, result of bio-grouting, stands out as such a problem where solute and solid transport phenomena, cell attachment, and cell/crystal growth mechanisms hold the key towards the formation of new, improved geo-materials. In the present study, focus is put on the real-time monitoring of the critical evolution of calcite precipitation within long trajectories in microfluidic chips. The total transport path, across which these phenomena are captured and interpreted, ranges between 1 and 1.5 meters to evaluate at which extend calcite crystal growth and deposition varies along the infiltrated porous chips. Results reveal varying number and sizes of crystals which precipitate across the flow path while qualitative characteristics are also discussed. Overall, the study aims to shed light into the previously underexplored, activation of the bio-cementation reaction, which governs nucleation, transport, and growth of calcite mineral binders and, therefore, influences the mechanical response of geo-materials subjected to bio-grouting applications.