Non-destructive evaluation of freeze-thaw performance in ISS-lime-fly ash stabilized saline soils

Abstract

Replacing conventional cement-based binders with cleaner materials for soil stabilization has become a research priority due to the pressing need to reduce carbon emissions in the construction sector. This study explores a sustainable stabilization method using ionic soil stabilizer (ISS), lime, and fly ash to improve the freeze-thaw durability of saline soils, which pose serious challenges to infrastructure in cold regions. A series of non-destructive testing methods, including elastic wave velocity measurements (S-wave and P-wave), time-domain reflectometry for volumetric water content analysis, and scanning electron microscopy, were employed to assess soil stabilization efficiency. The results indicate that ISS-lime-fly ash stabilization significantly enhances the freeze-thaw resistance of saline soils by promoting aggregate formation, improving cementitious bonding, and reducing the temperature sensitivity of water content in the frozen state. The evolution of S-wave and P-wave velocities revealed that ISS-lime-fly ash treated specimens exhibited greater structural integrity and slower degradation in mechanical properties compared to lime-fly ash treated soils. After 20 freeze-thaw cycles, the thawed ISS-lime-fly ash stabilized soils exhibited shear modulus values ranging from 1055 to 1325 MPa and small-strain Young's modulus values from 2973 to 3644 MPa. Integrating microstructural observations with existing research, this study elucidates freeze-thaw damage and self-healing mechanisms in stabilized soils while revealing the influence of ISS content on freeze-thaw behavior. These findings support the development of low-carbon soil materials for sustainable construction in cold and saline regions.