Laboratory and In Situ Stabilization of Compacted Clay through Granite Waste Powder

The main objective of this study is to investigate the effect of granite waste powder on the behavior of compacted clay soil in both field and laboratory environments. Samples were collected from clay soil exposed at Karak, Khyber Pakhtunkhwa, Pakistan. The sampled soils contain kaolinite, illite, and montmorillonites. The samples were mixed with various quantities, i.e., 10%, 20%, 30%, and 40% by weight of granite waste powder collected from various stone industries in district Mansehra, Khyber Pakhtunkhwa, Pakistan. They were then subjected to a variety of geotechnical testing in both the laboratory and the field, following the standard ASTM procedures. The results show that mixing with granite-cutting waste enhances the quality of the soil in both the field and laboratory settings by increasing its bearing capacity (BC), dry density (DD), California-bearing ratio (CBR), unconfined compressive strength (UCS), penetration resistance, and angle of internal friction and by reducing the optimum moisture content, cohesion, porosity, void ratio, and saturation potential. The resulting improvement is mainly due to the stronger, denser, and less hydrophilic character of the constituents of the added rock powders than the raw soil. It is observed that adding 40% granite waste powder produces the best outcome. However, there is a significant difference in the magnitude of the impact on soil quality between the laboratory and field testing. Owing to differences in the testing environment, soil volume, and compaction effort and energy, the amount of improvement is higher in laboratory testing than in field testing.