68th Canadian Geotechnical Conference and 7th Canadian Permafrost Conference

X-RAY CT OBSERVATION ON THE LIGHT BACKFILL

Session: Laboratory Testing I / Essais en laboratoire I

Grytan Sarkar, MASc Student (Canada)
Sumi Siddiqua, Assistant Professor (Canada)

Bentonite and / bentonite-sand mixture is widely used in the deep geological repositories for sealing nuclear wastes because of the high swelling capacity and low hydraulic conductivity, which largely depends on its microstructure as well as the pore space geometry. The microstructural behaviour such as pore size, pore distribution and pore connectivity of the LBF samples was investigated using Xradia Micro XCT-400. However to get a preliminary idea on the microstructural behaviour of the materials used in the LBF were observed. The X-ray source, detector, and a small portion of LBF specimen (5.5 mm in diameter) were placed closely to acquire a good quality image with a voxel size of 1.15 x 1.15 x 1.15 µm. The scanned images were de-noised and segmented to study the pore space geometry. An algorithm was developed to compute the volume porosity and pore-size distribution of the scanned samples. Additionally, the interconnected pore components and absolute permeability of the LBF samples were analyzed using Avizo software.