Progressive Growth of Calcium Carbonate During Microbially-Induced Calcium Carbonate Precipitation from a Microscale Viewpoint

Microbially-induced calcium carbonate precipitation (MICP) is an emerging technique that can improve the engineering properties of geomaterials. A microfluidic chip is designed to capture the MICP process in pore throats and large voids under flow conditions. Results show that the growth of crystals presents similar accumulative behaviors in those two areas, while the shapes of crystals are different. The precipitates formed in the pore throats exist as crystalline aggregates, whereas those in large voids present in the form of single crystals. The preferential growth at the upstream face is observed for the single crystal. The distinctions between the single crystal and the crystalline aggregates might result from different flow fields of the growth environment. Those preliminary results could advance the understanding of the growth behaviors of calcium carbonate and have implications for a wide range of applications.