Investigation on the microstructural characteristics of lime-stabilized soil after freeze–thaw cycles

Saline soil in Northwest China is susceptible to frequent and severe freeze–thaw cycles (FTC), resulting in railway and pavement disasters, emphasizing the need for stabilizing inadequately constructed soils. The engineering characteristics of soils can be changed after FTCs, which results from the variation of microstructure. Physisorption experiments (BET), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) were employed in this research to investigate how FTCs affected the micro-characteristics of lime-stabilized saline soil. According to the results, at the beginning of FTCs, the specific surface area (SSA) increased and then reduced after 3 FTCs. Moreover, the pores presented a bimodal characteristic and could be divided into inter- and intra-aggregate pores. The pore size distribution of the stabilized saline soil was altered by the FTCs. Additionally, the FTCs reduced the porosity of pores between 2 ∼ 22 μm and increased their complexity, while also creating more directional pore orientation. The results of this paper are believed to help advance soil stabilization methods and offer useful insights into the microstructural characteristics of lime-stabilized saline soil.