Effects of Bacterial Density on Growth Rate and Characteristics of Microbial-Induced CaCO3 Precipitates: Particle-Scale Experimental Study

Microbial-induced carbonate precipitation (MICP) has been explored for more than a decade as promising soil improvement technique. However, it is still challenging to predict and control the growth rate characteristics of CaCO3 precipitates, which directly affect engineering performance MICP-treated soils. In this study, we employ microfluidics-based pore-scale model observe effect bacterial density on precipitates during MICP processes occurring at sand particle scale. Results show that increases with in range between 0.6×108 5.2×108 cells/mL. Bacterial also affects both size number crystals. A low cells/mL produced 1.1×106 crystals/mL an average crystal volume 8,000 ?m3, whereas high resulted crystals (2.0×107crystals/mL), but smaller 450 ?m3. The were stable when was When 4–10 times higher, first unstable then transformed into This suggests should be important consideration design protocols.