Experimental Measurements of Degradation of Cementation in Contact-Bound and Void-Bound Cemented Sands

Soft rocks and cemented sands are ubiquitous in nature, and the mechanical response of such non-textbook soils has been extensively studied through experiments and discrete element modeling. The amount of cementation significantly influences the overall mechanical response. Depending on the amount of cementation, cemented sands can be classified into contact bound or void bound cemented sands. In this study, a micro mechanical study of cemented sands is carried out inside the X-ray computed tomography (XRCT), during one-dimensional compression. The kinematics of cemented quartz ensembles are examined with measures such as particle-scale rotations and displacements from the high-resolution XRCT scans. The differences and similarities in particle size distributions, coordination numbers, void ratios, particle displacement fields, cement disintegration, etc., in the contact and void-bound cemented sands are studied. Specifically, the quantification of the cementation present at the contacts or voids and its evolution with loading is presented here. The results obtained from the study indicate that the void-bound specimen has significantly higher stiffness than the contact-bound specimen and undergoes lesser cement disintegration. These results are critical for a multiple-length scale understanding of the behavior of cemented sands and benchmarking of constitutive models.