Li Xunchang, Miao Chenyu, Shi Zhengzheng
School of Geological Engineering and Geomatics, Chang'an University, Xi'an 710054, China.
Materials (Basel). 2025 Aug 13;18(16):3800. doi: 10.3390/ma18163800.
This paper explores how freeze-thaw cycles affect the mechanical properties and pore structure in cement-silt-modified eolian sand. The study addresses freeze-thaw durability issues for cold, arid region engineering. We tested samples with 5% and 8% cement content at a 3:7 silt-to-sand ratio using freeze-thaw cycling, unconfined compression tests, and an SEM. Gray relational analysis quantified pore-strength correlations. The results indicated that after 10 freeze-thaw cycles, the strength of the 5% cement content samples decreased by over 80%, while the strength of the 8% cement content samples decreased by approximately 25%. The total number of pores increased with the number of freeze-thaw cycles. The proportion of large pores also continued to rise. The pore shapes degraded from circular/elliptical to elongated. The pore orientation shifted from a concentrated distribution (90°~105°) to a more random dispersion. The proportions of large pores (with correlation coefficients exceeding 0.80) and extremely low abundance pores (with correlation coefficients exceeding 0.82) served as the primary microstructural parameters affecting strength loss. This research uncovered the freeze-thaw damage mechanism of cement-silt-modified eolian sand. It provides a theoretical foundation for material design in cold and arid region roadbed engineering and for enhancing the freeze-thaw resistance of modified materials.
本文探讨了冻融循环如何影响水泥-粉土改良风积沙的力学性能和孔隙结构。该研究解决了寒冷干旱地区工程中的冻融耐久性问题。我们使用冻融循环、无侧限抗压试验和扫描电子显微镜对水泥含量为5%和8%、粉土与沙子比例为3:7的样品进行了测试。灰色关联分析量化了孔隙与强度的相关性。结果表明，经过10次冻融循环后，水泥含量为5%的样品强度下降超过80%，而水泥含量为8%的样品强度下降约25%。孔隙总数随冻融循环次数增加。大孔隙比例也持续上升。孔隙形状从圆形/椭圆形退化成长条形。孔隙取向从集中分布（90°~105°）转变为更随机的分散分布。大孔隙（相关系数超过0.80）和极低丰度孔隙（相关系数超过0.82）的比例是影响强度损失的主要微观结构参数。本研究揭示了水泥-粉土改良风积沙的冻融破坏机制。它为寒冷干旱地区路基工程的材料设计以及提高改良材料的抗冻融性提供了理论基础。
