Macro-micro characteristics of geopolymer-stabilized saline soil in seasonal frozen soil region

Chemical stabilization is an effective approach to address various engineering problems related to saline soil, including salt heaving, frost heaving, dissolution, and corrosion. Through unconfined compression strength (UCS) test, x-ray diffraction (XRD) test, scanning electron microscope (SEM) tests and mercury intrusion porosimetry (MIP), this research investigates the macroscopic strength characteristics, microscopic mineral composition, and pore structure variation of quicklime, fly ash and sodium silicate joint solidifying sulfate saline soil under various freeze-thaw cycles, and discusses its solidification mechanism. The results indicate that when the contents of fly ash and sodium silicate are held constant, the unconfined compressive strength of the solidified soil increases first and then decreases with the increase of quicklime content. Additionally, the peak strength occurred at a quicklime content of 3%; The strength of all the solidified soils decreased with the increase of the freeze-thaw cycles and the solidified soils with the optimum quicklime content has a relatively strong ability to resist freezing and thawing; The influence of quicklime content on solidification is reflected in the formation of hydrate gels and the variation of pore structure; The influence of freeze-thaw cycle on solidification is reflected in the destruction of solidified pore structure.