Relation between pore size distribution, permeability, and cementitious gel formation in cured clay–lime systems

AbstractCylindrical specimens of a Devonian Red Marl with various amounts of lime (calcium hydroxide) were prepared and cured in a moist environment at various temperatures (25, 50, 75°C) from 1 to 24 weeks. As the gel forms and develops within the cured clay–lime composites, there is a general refinement in pore structure. Mercury porosimetry shows significant changes in pore size distribution within the clay–lime composites as the lime content, curing time, and curing temperature are increased. These changes are shown to be a result of the formation of increasing amounts of cementitious gel. The formation and growth of this gel results in appreciable increases in strength and are accompanied by a general decrease in permeability, although total porosity is in fact found to increase. This is accounted for in terms of a pore blocking mechanism by the developing gel.MST/689