Analyzing the performance of ground granulated blast furnace slag and marble powder as stabilizers in enhancing geotechnical properties of peat soil

Peat soils of northeast India are weak and highly compressible, yet low-carbon stabilization studies remain limited. This study examines the use of two industrial by-products, ground granulated blast furnace slag (GGBS) and marble powder (MP) applied individually and in blends to peat from Ziro Valley, Arunachal Pradesh. Fifteen mix variants (10%, 15%, 20% by dry weight) were assessed using geotechnical tests with microstructural support from SEM and EDX. Additives improved compaction, with maximum dry density rising from 12.998 kN/m³ (untreated) to 14.45 kN/m³ (S + 15% GGBS + 20% MP), accompanied by lower moisture demand. Strength gains were notable: GGBS at 15% gave a soaked CBR of about 5.9%, while the combined S + 20% GGBS + 20% MP mix achieved the highest values (unsoaked = 8.5; soaked ≈ 7.2), more than twice that of untreated peat. SEM/EDX confirmed denser matrices and pozzolanic products enhancing stabilization.