Microstructural remodeling and mechanical enhancement of expansive and clayey soils induced by magnetized water

The stabilization of expansive and clayey soils remains a persistent challenge in geotechnical engineering. This study investigates the potential of magnetized water—a sustainable, physical treatment method—to enhance the engineering properties of such problematic soils. Through a comparative analysis using expansive and clayey soils from Nanjing, China, we evaluated changes in particle size distribution, Atterberg limits, permeability, compaction, and shear strength. The results indicate that magnetized water treatment induces the disintegration of coarse soil aggregates, shifting the particle size distribution toward finer fractions. This microstructural remodeling significantly improved mechanical performance: shear strength cohesion increased by 61.8%, the internal friction angle rose by 17.8%, and the maximum dry density improved. Hydrologically, the treatment reduced the plasticity index by up to 33.4% and decreased permeability due to the pore-filling effect of the dispersed fine particles. Scanning electron microscopy and porosity analyses support a microscale mechanism wherein the enhanced solubility and altered molecular cluster structure of magnetized water dissolve aggregate cementation, promoting a denser, more stable soil matrix. These findings suggest that magnetized water offers a viable, eco-friendly alternative to chemical binders for soil improvement applications.