Microbial Induced Calcium Carbonate Precipitation in Bangkok Clay using Microencapsulated Bacterial Spore

Abstract

Microbial Induced Calcium Carbonate Precipitation (MICP) is a new promising method for ground improvement. It has been widely reported that the MICP is efficiently used in porous media like sandy soil. This study aims to conduct a preliminary research on an application of MICP in clayey soil. In this study, encapsulated ureolytic bacterial spores prepared by a freeze-dried technique were used as treatment agent. The Bangkok clay specimen was reconstructed by oven-drying and grinding as powder. The treated soil specimens can be easily prepared from soil powder. To evaluate the efficiency of MICP process, the mechanical properties of MICP-treated soil were examined by destructive and non-destructive tests such as unconfined compression test and free-free resonant frequency test. Microstructure and chemical properties of MICP-treated soil were also examined by X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). The study can indicate a suitable amount of microencapsulated MICP bacterial spore for improving the strength and stiffness of Bangkok Clay.