Grain-Scale Tensile and Shear Strengths of Glass Beads Cemented by MICP

This study explores the mechanical behavior of glass bead pairs cemented by microbial induced calcite precipitation (MICP) when subjected to tensile or shear loading. The mineral precipitation habit and contact area are also examined using X-ray computed tomography (X-ray CT). Examination of the failure surfaces reveals three distinctive failure modes: debonding failure at the precipitate-grain interface, internal failure within the precipitate, and mixed failure. The internal failure mode appears dominant when the calcite content (CC) of the bonded glass bead pair is greater than 17%, and it results in the smallest strengths: ∼8 kPa in tension and ∼7 kPa in shear. When CC is less than 17%, the debonding failure mode is mostly observed, and the debonding failure leads to the greatest strengths: ∼35 kPa in tension and ∼13 kPa in shear. The mixed failure mode occurs when 11%