Improvement of Soil Stability and Strength by Integrating Industrial Waste Materials Fly Ash and Steel Slag

Soil acts as the primary supporting medium for all civil engineering structures. The performance of foundations, pavements, and embankments largely depends on the strength and stability of the underlying soil. However, clayey soils often exhibit low bearing capacity, high plasticity, and significant volume changes due to moisture fluctuations, making them unsuitable for direct construction use, while conventional stabilizers such as cement and lime are effective, their production is costly and environmentally intensive. Industrial by-products like fly ash and steel slag offer a sustainable alternative. Fly ash contributes to strength development through pozzolanic reactions, whereas steel slag improves particle interlocking and stiffness. The utilization of these materials not only enhances soil performance but also supports eco-friendly waste management. The rapid growth of industries residue should be large quantity of waste material in form of slag and ashes. These materials can be used for soil stabilization due to containing some useful elements like Silica oxide (SiO2), Calcium oxide (CaO)) Iron Oxide (Fe2O3) and Steel and other element needed for the soil’s gripping Waste material like Steel slag and Fly ash Class F (produced from burning anthracite or bituminous coal, having low amount of calcium fly ashes with carbon contents less than 10%) can add with Clayey Soil in proportion ratio to improve soil behavior and its strength. The mix proportion of industrial waste material i.e. Steel Slag is taken in the ratio of 13% , 26% & 39 % and Fly Ash are taken in ratio of 7% , 14 % 21% respectively. The examinations conducted to assess geotechnical properties include tests for water content, specific gravity, sieve analysis, liquid limit, and plastic limit. These tests show the results of Steel slag and Fly ash that it improves the geotechnical properties of the soil samples with the waste material Steel slag and fly ash of Class F is useful for clayey soil. The optimum values of mixed material for higher California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) value are achieved in mix ratio 66 % Clayey Soil, 21 % Fly Ash and 13 % Steel Slag