| This study encompasses a comprehensive investigation of fine particle behavior, its dependence on pore fluid characteristics, and the application of this enhanced understanding to fabric control for the development of engineered fabrics. The systematic physical analysis of previously published studies is complemented with an extensive battery of tests that take into consideration surface charge control through pore fluid characteristics (i.e., pH and ionic concentration), single mineral systems and mixtures (kaolinite and calcium carbonate) and mineral surface modification with polymers. Additional considerations include the effects due to mineral dissolution, particle shape (platy, blocky and rhombahedral), relative particle sizes and masses. The behavior of both individual mineral systems and mineral mixtures is studied through macroscale tests involving a wide range of solid volume fractions and strain levels. Scanning electron microscopy is also used to verify particle associations.; A detailed fabric map on the pH-ionic concentration space is suggested on the basis of physical analyses, and it is experimentally corroborated. Furthermore, the influence of an anionic polymer on single or mixed mineral systems is surface-charge dependent, i.e. the response depends on the type of kaolinite or calcium carbonate particles and the pore fluid characteristics. Single minerals become more readily dispersed, while the tendency to particle association prevails in kaolin-carbonate mineral systems. Electrostatic interactions, particle shape, and relative mineral content determine the final fabric of mixed-mineral systems. In the presence of a divalent cation, the ratio of added cations to the number of polymer binding sites determines the level of particle associations within single and mixed mineral systems treated with a polymer. |
