This study explores the feasibility of using coal bottom ash (CBA) as an alternative material for constructing highway embankments, aiming to reduce reliance on traditional resources by utilizing industrial waste. The assessment involves both experimental investigations and numerical analyses. The experimental phase includes a comprehensive analysis of the physicochemical and geotechnical characteristics of CBA, providing essential data for subsequent numerical evaluations. Numerical analysis, conducted using Plaxis 3D, evaluates the stability of embankments constructed with CBA at various heights (3 m, 4 m, and 5 m) and slope angles (30, 45, and 60°) under wheel loads, employing the Mohr–Coulomb Model. The results indicate that the factor of safety exceeds the minimum thresholds set by the Indian Road Congress (IRC). The embankment with a height of 5 m and a slope angle of 30° has the highest safety factor at 2.25, while the embankment with a height of 4 m and a slope angle of 60° has the lowest safety factor at approximately 1.58. Vertical deformations observed across all three slope angles for different heights are comparable. The findings provide a sustainable alternative by reducing the dependence on natural resources. It can also reduce the coal ash deposited in landfills, mitigating waste management challenges and other environmental hazards like ash dyke spilling and groundwater contamination.