Examination of Silt-Size Particle Matrices Using X-Ray MICRO-CT Imaging: Advancements, Selected Findings, and Challenges

Abstract The mechanical behavior of silts is significantly influenced by the soil particle fabric (i.e., spatial arrangement of individual particles) in addition to the well-known effects arising from void ratio and effective confining stress. Unlike for sandy soils, the research work conducted on the fabric of silt matrices (particle size ~2 to 74 μm) is scarce. A research program is undertaken to systematically investigate the fabric of silt particle matrices using non-destructive, X-ray micro-computed tomography (micro-CT) imaging technology. The imaging of matrices of commercially available, uniformly graded, pre-calibrated, standard size spherical silt particles (mean particle size of 50 μm) provided useful insights on the ability of micro-CT imaging to capture particle size, shape, volume, and determine scalar fabric parameters such as void ratio. The objective is to extend the work to fundamentally examine the silt particle matrices of natural silts, and in turn, support the geotechnical engineering characterization of the complex stress-strain behavior of silts.