LalfakzualI Talkeri, H.T.Raghuram, K.C.Chiranjeevi, K.2026-02-062024Lecture Notes in Civil Engineering, 2024, Vol.529 LNCE, , p. 33-4323662557https://doi.org/10.1007/978-981-97-4852-5_3https://idr.nitk.ac.in/handle/123456789/28958Spent coffee residue contains a significant amount of biodegradable material and is extremely organic. This study aims to assess the feasibility of blending the soil with spent coffee residue and industrial by-products such as fly ash and slag through a sustainable approach using the geopolymerization technique. Geopolymerization was induced using fly ash (FA) and slag as precursors with sodium hydroxide and sodium silicate as alkaline activators. Modified compaction was investigated to determine the optimum moisture content and bearing strength of the mixes produced. The Taguchi's L-9 orthogonal array served as the foundation for the formulation of all nine geopolymer mixes created herein. In an initial calibration phase, the durability and unconfined compressive strength (UCS) characteristics of a set of nine mixes were utilized for performance evaluation. On the basis of these findings, strength and durability prediction equations were developed. In the prediction phase, the accuracy of the developed model is evaluated with actual test results from trials on the nine mixes. Partial replacement of slag by 20 and 30% with the desired sodium oxide content range between 3 and 5% complied with the standard for subgrade material. Test results indicate stabilized coffee residue might be used as subgrade material rather than being dumped in landfills. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Durability testGeopolymerSlagSpent coffee residueUCS