Our paper titled “Shear and Tensile Strength Measurement of CaCO3 Cemented Bond Between Glass Beads Treated by Microbially Induced Calcite Precipitation (MICP)” has been accepted for publication in the Journal of Geotechnical and Geoenvironmental Engineering.
Gao K., Lin H., Suleiman M.T., Bick P., Babuska T., Xiwei Li, Helm J., Brown D.G., and Zouari N. 2023. “Shear and Tensile Strength Measurements of CaCO3 Cemented Bonds Between Glass Beads Treated by Microbially Induced Carbonate Precipitation (MICP)” Journal of Geotechnical and Geoenvironmental Engineering. 149(1):04022117.
The particle-scale shear and tensile strength measurements of Microbial Induced Calcite Precipitation (MICP) treatment have been investigated in this paper. Glass beads were used to represent sand particles. Three particle-scale test setups were developed to measure the tensile, shear, and cyclic shear strength of MICP treated CaCO3 bonds between glass beads. Sporosarcina pasteurrii bacteria were introduced to precipitate CaCO3 and form cementation bonds between glass beads. Preliminary particle-scale test (Test setup 1) was initially designed to measure the shear and tensile strength of CaCO3 bonds precipitated between glass beads mounted on optical fiber sensors with known properties. Shear and tension loads were applied to the CaCO3 bonds by the displacement actuators controlling the movement of movable stages. The deflection (measured in the tension test) and strain (measured in the shear test) of optical fibers were recorded to calculate the tensile or shear strength of the CaCO3 bonds. The improved particle-scale test setup (Test setup 2) was developed using a larger and stable reaction chamber, an automated injecting system, and stiff bending elements (instead of optical fibers) that were connected to glass beads to increase the success rate of measurement. The deflections of bending elements were measured to calculate the tensile and shear strength of the CaCO3 bond using the beam theory. The enhanced particle-scale test setup (Test setup 3) was developed to directly measure the shear and tensile forces generated in CaCO3 bonds using load cells and LVDTs to investigate the cyclic response of the CaCO3 bonds. For the tests using Test setup 3 with 100 and 200 μL bacteria injections, the shear and tensile strengths were ranged from 321 to 378 kPa and from 353 to 446 kPa, respectively.