Sustainable Improvement of Highly Plastic Clay Using Magnetized Water

Expansive clays pose ongoing serviceability and safety challenges owing to their pronounced swell-shrink behavior in response to moisture fluctuations. Conventional stabilization using cement-based and industrial waste materials results in significant carbon emissions and environmental impact burdens. In the search for sustainable alternatives, magnetized water (MW) has emerged as a potentially eco-friendly and innovative solution. However, its utilization in the field of geotechnical engineering remains unexplored. This study aims to present a comprehensive investigation into the effectiveness of MW as a promising green and sustainable technology for stabilizing highly plastic soils. MW was produced by passing ordinary water (OW) through a magnetizer tube, subjected to multiple passes (1, 3, 6, and 9) through the magnetic field. Laboratory tests were conducted on two sets of clayey soil samples: one mixed with OW and another with MW. To investigate the degradation of magnetic efficacy over time, this study also assessed various curing and post-magnetization mixing periods. Results indicated that MW is an effective stabilizing agent for plastic soils, with density, compressive strength, and pre-consolidation pressure increasing by 9.1%, 86%, and 50%, respectively. Additionally, it reduced plasticity, free swell, linear shrinkage, and optimum moisture content by 41%, 86%, 73%, and 45%, respectively. Statistical analysis shows that the improvement beyond six passes was marginal, indicating that six passes represent the optimal condition for achieving maximum improvement. Statistical analysis also confirms no difference between immediate use of MW and after 12 h. of storage. From 12 h. to 7 days of storage prior to mixing, the improvement progressively decreased with increasing the storage, revealing a gradual attenuation of magnetic efficacy with time. After 12 days of storage prior to mixing, MW became statistically indistinguishable from OW. Therefore, MW remains practically meaningful for field application for subgrade and embankment improvement when generated on demand and used promptly, while long‑term storage of MW is not recommended.