Red mud, a by-product generated during the extraction of aluminium from bauxite ore, poses challenges to the alumina industry due to its inherent sodicity, alkalinity and heavy metal content. Consequently, studies related to its bulk utilization and valorization have gained attention in the construction sector to promote sustainability. However, utilization of red mud in stabilization of expansive soils using alkali activation is seldom explored. Therefore, this study focuses on improving the geotechnical properties of an expansive soil (black cotton soil, BCS) through chemical stabilization by using blends of two distinct industrial wastes, viz. red mud and GGBS, termed as GGRM, activated with sodium hydroxide (NaOH) solution. The strength, stiffness and durability characteristics of these compacted blends were assessed based on a series of laboratory investigations like unconfined compressive strength, ultrasonic pulse velocity and wet-dry cycles tests. Leachate analysis was also performed to assess the geo-environmental issues of soil ameliorated with blends of alkali-activated GGRM blends. These blended specimens were moulded with different molar concentrations of NaOH solutions (i.e. 2, 5 and 10 M). Further, microstructural studies were carried out through XRD, SEM-EDS and FTIR analysis. The results show that heavy metal contents in alkali-activated specimens are within the permissible limits of USEPA guidelines. Based upon the assessments of strength, durability and P-wave velocity after 28 days of curing period, 25 and 30% binder contents of GGRM100:00, GGRM70:30 and GGRM50:50 corresponding to 5 M and 10 NaOH, were found suitable for subgrade applications in accordance with IRC 37 guidelines.

来源平台：INDIAN GEOTECHNICAL JOURNAL