Compacted lateritic soil treated with blast furnace slag as hydraulic barriers in waste containment systems

Abstract

Laboratory testing was conducted to assess the feasibility of using lateritic soil mixed with up to 15% blast furnace slag (BFS) by dry weight of soil as a suitable hydraulic barrier. Tests were carried out on the lateritic soil-slag mixture to ascertain the particle size distribution, index properties and compaction characteristics. The relationship between hydraulic conductivity, unconfined compressive strength (UCS) and volumetric shrinkage strain at standard Proctor, West African Standard and modified Proctor, compactive efforts were determined at different moulding water contents (i.e., 10-20%). Acceptable zones on the compaction plane in which compacted soil specimens would have low hydraulic conductivity (< 1 × 10−9 m/s), minimum volumetric shrinkage strain (< 4%) and high compressive strength (< 200 kN/m²) were established. The results showed that higher slag contents improved the hydraulic conductivity, volumetric shrinkage strain and compressive strength. Optimum properties of the lateritic soil-slag mixture were obtained at 10% slag treatment that suggests the use of the mixture as a suitable hydraulic barrier in waste containment systems.