Stabilization of expansive soil through MICP and jute fiber reinforcement: strength and shrink-swell analysis

Abstract

Expanding on the challenges of expansive soils to civil infrastructure, this research delves into the synergistic application of microbially induced calcium carbonate precipitation (MICP) through bio-stimulation and natural fiber reinforcement to mitigate soil swell-shrink behavior and enhance soil strength. This research diverges from traditional methods by addressing their economic and environmental limitations. The dual strategy of bio-stimulation with natural fiber reinforcement was assessed through laboratory tests, including unconfined compression, 1D swell, linear shrinkage tests, and microstructural analysis. This methodology involved preparing solutions to foster bacterial growth and strategically adding jute fibers to enhance the soil matrix. Results revealed significant improvements in soil strength (up to 186%), and reductions in swell strain (up to 85%) and swell pressure (up to 90%), with the optimal jute fiber content at 1.5%. Additionally, a significant increase in calcium carbonate content (163–176%) highlighted bio-stimulation's role in soil stabilization. SEM analysis showed that bio-stimulation and jute fiber reinforcement transformed the soil microstructure, enhancing cohesion and reducing deformability. These outcomes highlight the promise of combining bio-stimulated MICP with natural fiber reinforcement as an eco-friendly and efficient approach to soil stabilization. They also add to the growing body of knowledge on tackling the issues posed by expansive soils in civil engineering applications.