Sustainable incorporation of Plaster of Paris kiln dust for stabilization of dispersive soil: A potential solution for construction industry

The presence of dispersive soils in the region of Khushab, Pakistan, has been recognized as a significant element causative to numerous challenges in construction. This research intended to examine the efficacy of Plaster of Paris kiln dust (PKD) as a cost-effective and eco-friendly material in stabilizing the strength properties and dispersion potential (DP) of dispersive soil at optimal curing period. Different contents of PKD (from 0.5% to 3%) were added to the soil. A series of tests have been carried out over various curing times (0, 7, 14, 28, and 60 days) to evaluate the effectiveness of PKD as a stabilizing agent. The tests included a double hydrometer, Atterberg limits, specific gravity, compaction, unconfined compression strength (UCS), consolidation, physiochemical properties (pH, Electrical conductivity), and chemical analysis (percentage sodium, sodium adsorption ratio). The results illustrated that DP decreased from 74.12% to 8.57% while the increase in UCS value was observed from 124.3 kPa to 1212.5 kPa (an increase of 875%) by increasing PKD up to 3% after curing for 60 days. The X-ray diffraction and scanning electron microscopy exhibited the development of cementitious products (Calcium silicate hydrate, Calcium aluminate hydrate) due to the pozzolanic reaction with 3% PKD after a curing time of 28 days, which is responsible for the increment in strength. PKD exhibits both favorable economic and environmentally friendly characteristics, as it has the lowest cost among several additives used previously and provides a significant portion of the treated area (92.6%) free from pollution and landfill. PKD improved the stability and strength of dispersive soil and provided a sustainable waste management solution, making it a highly viable option for soil improvement applications in the construction industry.