Freeze-thaw resistance of eco-material stabilized loess

Abstract

In the Loess Plateau in Northern China, repeated freeze-thaw (FT) cycles deteriorate the strength and structure of loess as a foundation soil, resulting in the instability or failure of supporting structure. Lignosulfonate is an eco-material, utilized as an effective and nontraditional stabilizer to improve the engineering properties of metastable soils. A series of laboratory tests, including unconfined compression tests, cyclic loading-unloading tests and scanning electron microscopy, on calcium lignosulfonate (CL)- and sodium lignosulfonate (SL)-stabilized loess were performed to investigate the stabilization effect, deterioration mechanisms of the FT cycles, and the resistance to FT cycles. Two traditional stabilizers, quicklime (QL) and sodium silicate (SS), were selected, and the engineering properties of QL- and SS-stabilized loess were compared with those of CL- and SL-stabilized loess. The results showed that the strength values of CL- and SL-stabilized loess specimens decreased by 34.2% and 50% respectively, after 20 FT cycles, whereas those of the traditionally SS- and QL- stabilized specimens decreased by 85.3% and 82.87%, respectively. The elastic moduli of SL- and QL-stabilized loess specimens decreased by 22.1% and 92.0%, respectively. The mean energy dissipations of nontraditionally treated specimens also decreased significantly less than those of traditionally treated specimens. Overall, the results showed CL and SL had better stabilization effects on engineering properties of loess than QL and SS, and their stabilized loess specimens exhibited stronger resistance to FT cycles. The study findings demonstrated the significant potential of lignosulfonate for extensive application in cold loess areas.