Potential of microbially induced calcium carbonate precipitation (MICP) on the ancient masonry foundation

Historical buildings are located in the open air without protection, which exposes them to deterioration of the
constructed materials and eventually results to the structural instability. This study examined the efficacy of microbially induced calcium carbonate precipitation (MICP) in ancient foundations consisting of bricks and mortars. This method of improvement complies with the requirements of the Fine Arts Department that does not allow the vibration around the area of the historical site. The microorganism namely “Lysinibacillus
sphaericus LMG 22257” was used in this study in which this microorganism was classified as a high potential for calcium carbonate production. Tested bricks (from the factories in Phra Nakhon Si Ayutthaya province) and mortars were made according to the Fine Arts Department’s suggestion. In the tests,
both bricks and mortars were submerged in solution of microorganism for 18 days. The microstructural development at material’s surface was evaluated using a Scanning Electron Microscope, mineral content was determined using an Energy Dispersive X-ray Spectrometer, and change in material's surface
depth was evaluated using 3D Optical Surface Profilers. The results revealed that the MICP can allow to provide the reduction in the cracks and pores on the material’s surface. Therefore, it can be concluded that the MICP method can be adopted for improving the quality of the ancient foundations.