Desiccation-Induced Volumetric Shrinkage of Compacted Metakaolin-Treated Black Cotton Soil for a Hydraulic Barriers System

摘要

Black cotton soil treated with up to 24% metakaolin (MCL) content was prepared by molding water contents of a?’2, 0, 2, 4 and 6% of optimum moisture content (OMC) and compacted with British Standard Light (BSL) and West African Standard (WAS) or a€?Intermediatea€? energies. The specimens were extruded from the compaction molds and allowed to air dry in a laboratory in order to assess the effect of desiccation-induced shrinkage on the compacted mix for use as a hydraulic barrier in a waste containment application. The results recorded show that the volumetric shrinkage strain (VSS) values were large within the first 10 days of drying; the VSS values increased with a higher molding of the water content, relative to the OMC. The VSS generally increased with a higher initial degree of saturation for the two compactive efforts, irrespective of the level of MCL treatment. Generally, the VSS decreased with an increasing MCL content. Only specimens treated with a minimum 20% MCL content and compacted with the WAS energy satisfied the regulatory maximum VSS of 4% for use as a hydraulic barrier.