Properties of Slag-Based Geopolymer-Stabilized Indian Lithomargic Soil Using Sugarcane Bagasse Ash for Sustainable Pavement Design

This investigation examines the feasibility of stabilizing lithomargic soil subgrades through the utilization of geopolymerized slag (GGBS) and sugarcane bagasse ash (SCBA). Through a series of compaction experiments, the best dry density was obtained by maintaining a constant slag dosage of 10% by weight of the soil while altering the dosage of SCBA. The geopolymeric aqueous solution is produced by combining water glass (Na2SiO3) and caustic soda (NaOH). The soil mixtures were subjected to both unstabilized and stabilized UCS and CBR experiments. The experiments suggest that the strength of subgrade soil enhances with the inclusion of SCBA up to a specific threshold (i.e., 15%), after which it decreases due to a constant dosing of slag. In order to comprehend the hardening performance subsequent to geopolymer stabilization, the microstructural analysis is implemented. The establishment of co-relationships among the strength parameters (UCS and CBR) facilitated the formulation of a simple linear regression model in order to comprehend the relationship among the strength parameters of geopolymer-stabilized lithomargic soil. The long-term effectiveness of mechanical performance was disclosed by the boost of strength performance, as evidenced by the prolonged CBR and UCS achievement. This study also suggests a pavement design that adheres to the Indian Roads Congress principles for low-volume roadways, which results in a substantial reduction (45%) of entire pavement thickness while maintaining performance. The economic benefits of geopolymer stabilization in rural pavement construction were revealed through a comprehensive cost analysis that compared the conventional and modified pavement designs while also maintaining the sustainability element.