Multi-objective optimisation on bottom ash–soil stabilised MSW using Taguchi

The current research is a study on the possibility of using stabilised municipal solid waste (SMSW) mixed with bottom ash (BA) and soil as a material to be used as a sustainable subgrade in building roads. A Taguchi L₁₆ (4²) orthogonal array was used to prepare 16 mixes with BA and soil as control variables and assess the impact of the control variables on optimum moisture content, maximum dry density, California bearing ratio, unconfined compressive strength (UCS), and organic matter (OM). In order to determine compaction, strength, and stabilisation behaviour, laboratory testing was performed. Analysis of variance statistical assessment showed that BA had the greatest effect on UCS, and soil on OM reduction. Taguchi optimisation has figured out that the blends with moderate BA levels and increased soil content enhanced density, strength, and stability of the blends. The overall performance was further validated using multi-criteria decision-making methods, which consistently ranked the mix with moderate BA and higher soil content as optimal. The results confirm that the combined use of limited BA and soil enhances the mechanical behaviour and environmental suitability of SMSW, demonstrating its potential as a cost-effective and sustainable material for pavement subgrade applications.