Preparation and identification of clay samples with controlled fabric

Abstract

Techniques have been developed to prepare reasonably homogeneous, reproducible bulk samples of a kaolinite clay (Hydrite 10) with predetermined microfabrics and to reliably identify these microfabrics both quantitatively and qualitatively. Eight samples with quite diverse histories were produced in the laboratory by controlling the chemistry of the clay-water system, the consolidation stress path (either isotropic or anisotropic), and the magnitude of the consolidation stresses. The fabrics of these samples are identified and quantified by the combined use of scanning electron microscopy, optical microscopy, and X-ray diffractometry, and reasonably comprehensive appraisals of particle associations and orientation are obtained. Anisotropic consolidation was found to induce a preferred particle orientation, whereas isotropic consolidation tended to provide basically random samples. The anisotropically consolidated samples from dispersed slurries exhibited somewhat greater particle orientation than those from flocculated slurries, and, although considerable particle orientation occurred at low values of the consolidation stress, increases in the major principal consolidation stress did accentuate the particle orientation. The presence of domains or small groups of particles is suggested in certain samples, especially in those consolidated isotropically.