Volume Change Behavior of Amended Expansive Soil Using Sugarcane Bagasse Ash-Based Geopolymer

This study aimed to address pavement cracking caused by the high swell-shrink behavior of expansive soils, resulting from fluctuations in moisture content and high clay content, by using an eco-friendly nontraditional additive: sugarcane bagasse ash (SCBA) based geopolymer. The study involved a dry mixture of soil and SCBA, mixed with a liquid alkaline activator consisting of a fixed 70 : 30 weight ratio of 1 M sodium metasilicate and 10M sodium hydroxide. By varying the SCBA content from 5% to 30% by weight of dry soil and keeping the amount of liquid alkaline activator constant, the volume change behavior of the expansive soil was observed. The swelling and compressibility characteristics of treated samples were tested using an oedometer test, while the shrinkage and plasticity characteristics were observed through consistency limit tests after 1, 3, 7, and 14 days of curing. X-ray diffraction and field emission scanning electron microscope tests were utilized for chemical composition and microstructural analysis. The results showed a substantial decrease in the swelling pressure, shrinkage limit, compressibility index, and plasticity index of treated samples by 100%, 100%, 90%, and 100%, respectively. The study revealed that the aluminosilicates in SCBA react with the alkaline solution to form cementitious gels, which bind the soil particles and encapsulate them, thereby stabilizing the expansive soil for volume change. These findings have significant implications for the advancement of knowledge in soil stabilization based on geopolymers, presenting an alternative solution for stabilizing pavement subgrade. Roads are crucial infrastructure that require a stable foundation. Expansive soils can pose a significant challenge in road construction, leading to road damage and increased maintenance costs due to its swelling and shrinkage behavior when moisture is added or removed (i.e., in the rainy or dry season especially). Also, the foundation of structures is critical in ensuring the safety and stability of buildings. Expansive soils can lead to cracks or structural failures. This behavior can be controlled by adding some stabilizing material. One such material used in this study is SCBA-based geopolymer. It can provide a cost-effective solution to stabilize expansive soils and enhance the road's durability by stabilizing its volume change behavior, enhancing its strength and the overall stability of the structure. The use of SCBA geopolymer has practical applications in a range of geotechnical applications such as road construction, airport runways, industrial parks, parking lots, and sports fields. By using this solution, we can improve the stability and durability of construction projects, reduce maintenance costs, and enhance safety.