Study of the local contact properties evolution during in situ dissolution of two biocemented sand grains

Microbially-induced calcite precipitation (MICP) is a biocementation technique representing a promising sustainable tool for soil reinforcement. In the case of technical applications of MICP, the durability of biocemented materials, such as sand, in aggressive environments must be evaluated. Exposure to weakly acidic waters, for example, triggers the dissolution of calcium carbonate (CaCO3) crystals that bridge the sand grains and decreases the strength of the material. The mechanical properties of biocemented sand are linked to the contact properties due to the CaCO3 crystal bridges. Here, we aim to investigate the role of the different polymorphs and orientations of CaCO3 crystals on the evolution of the contact properties during dissolution. The possibility of coupling diffraction-tomography techniques will contribute to gaining complementary insights on the long-term assessment of the durability of biocemented sand in hostile environments.