In Situ X-ray Tomography and 3D X-ray Diffraction Measurements of Cemented Granular Materials

摘要

In situ x-ray tomography and three-dimensional (3D) x-ray diffraction analysis have been combined to investigate the mechanical behavior of noncemented and lightly cemented quartz particles under quasistatic confined uniaxial compaction. The motivation for this study is to understand the particle-scale origin of the mechanical behavior of cemented particulate materials and to isolate what makes this behavior distinct from that of noncemented particulate materials. Tomography measurements elucidated the particle packing structure, contact fabric, cementation, and particle fragmentation, while 3D x-ray diffraction measurements provided insight into particle rotations and particle-resolved strain and stress tensors. The cemented sample was found to exhibit higher resistance to individual particle fragmentation and significantly restrained particle motion, compared with the noncemented sample, likely due to the cement bridges between particles. This reduction in particle fragmentation and motion may explain the significantly enhanced macroscopic stiffness of the cemented sample, as well as the strong alignment of intraparticle principal stresses with the macroscopic strain direction. These findings advance particle-scale understanding of cemented granular media and provide motivation for further research focused on developing fundamental understanding of the constitutive response of these materials.