Microstructural evolution of buffers

摘要

A buffer consisting of blocks of compacted Nabentonite powder absorbs water by which the grains expand andexfoliate, yielding clay gels that occupy the voids between them.The expandability of the grains and thereby the bulk density andhydraulic conductivity depend on the density of the gel fillingsand hence on the grain density. Since the porewater electrolytesaffect the pore size distribution of the gels they have an impact onthe hydraulic conductivity as well. The density distribution inmatured MX-80 clay determines both the hydraulic conductivityand the ion diffusion transport as well as the swelling pressure. Incan be evaluated from micrographs covering a sufficiently largefraction of a cross-section of the clay.