Enhancing the properties of lateritic soil using industrial waste as an alternative to cement in pavement construction

Abstract The increasing demand for sustainable construction materials has driven efforts to replace traditional cement-based stabilizers because of their high carbon footprint. This study investigated the use of industrial wastes namely copper slag (CS), iron ore tailings (IOT), and red mud (RM) as eco-friendly alternatives to cement for stabilizing Lateritic Soil (LS) in pavement subgrades. A comprehensive experimental program was used to assess the effects of these additives on the Atterberg limits, compaction characteristics, unconfined compressive strength (UCS), California bearing ratio (CBR), permeability, and fatigue life. Among the stabilizers, 30% CS yielded the most promising. Results reducing the plasticity index from 14% to 8%, increasing the maximum dry density to 2.15 g/cc (from 1.93 g/cc), and decreasing the optimum moisture content to 10.5%. After 28 days of curing, the UCS increased from 365 kPa to 1121 kPa (a 207% improvement), whereas the unsoaked and soaked CBRs rose from 20% to 73% and from 6% to 18.8%, respectively. The fatigue life at 1/3 UCS improved from 5,324 to 87,351 cycles, exceeding that of the 6% cement-treated soil (73,221 cycles). The CS-stabilized soil also demonstrated moderate permeability (1.35 × 10⁻⁵ cm/s) and improved microstructural bonding, as confirmed by SEM analysis. These results validate 30% CS as a high-performance, low-carbon alternative to cement for enhancing LS in pavement subgrades, offering both environmental and engineering benefits. Moreover, utilizing these industrial byproducts aligns with circular economy principles by reducing the demand for cement a major contributor to CO₂ emissions thus offering a sustainable pathway for infrastructure development.