Bio-chemical reactions enable the production of biomimetic materials such as sandstones. In the present study, microbiologically-induced calcium carbonate precipitation (MICP) is used to manufacture laboratory-scale specimens for fracture toughness measurement. The mode I and mixed-mode fracture toughnesses are measured as a function of cementation, and are correlated with strength, permeability and porosity. A micromechanical model is developed to predict the dependence of mode I fracture toughness upon the degree of cementation. In addition, the role of the crack tip T-stress in dictating kink angle and toughness is determined for mixed mode loading. At a sufficiently low degree of cementation, the zone of microcracking in the vicinity of the crack tip is sufficiently large for a crack tip K-field to cease to exist and for crack kinking theory to not apply. The interplay between cementation and fracture properties of sedimentary rocks is explained; this understanding underpins a wide range of rock fracture phenomena including hydraulic fracture.
@article{arxiv.2311.07785,
title = {Fracture of bio-cemented sands},
author = {C. Konstantinou and E. Martínez-Pañeda and G. Biscontin and N. A. Fleck},
journal= {arXiv preprint arXiv:2311.07785},
year = {2023}
}