Insights on the textural and crystallographic properties of calcite obtained through MICP using advanced synchrotron diffraction imaging

The microbially induced calcite precipitation (MICP) technique is used to turn sand into a cohesive medium by inducing the precipitation of calcite crystals in the pores. This work presents, for the first time, a comprehensive study of the morphological and crystallographic properties of bio-induced calcite using scanning 3D X-ray diffraction and phase contrast tomography, highlighting possible implications of the calcite precipitation process on the microstructure of biocemented sand. The combined approach of diffraction and imaging techniques with laboratory characterization tools revealed the link between morphology and crystallinity of bio-induced calcite crystals and the preferred orientation of crystals at the surface of sand grains. These results provide useful insights not only into the role of the crystallographic properties of calcite in determining the microstructure of biocemented sand but also on the influence of Sporosarcina Pasteurii on the precipitation process. The potential of scanning 3D X-ray diffraction in tackling challenges related to construction and geomaterials is demonstrated.