Subgrade soil is sometimes modified with lime to improve strength. In this study, lime modified soil (LMS) specimens are subjected to freezing–thawing cycles, the mechanical properties and microstructure of the specimens are investigated by resilient modulus test and scanning electron microscope test. The variation in pore microstructure is investigated by image analysis. The results indicate that the number and area of micropores are reduced due to phase change and expansion of water in the soil under freezing–thawing cycles, and the micropores are subsequently coalesced into macropores. The variations in porosity and resilient modulus are correlated. The largest effect to the microstructure and resilient modulus of LMS is observed after the first freezing–thawing cycle. The main reason for the attenuation in resilient modulus of LMS is attributed to the increase in porosity, decrease in bond strength among soil particles and increase in the number of narrow and long cracks in soil.

路基土壤有时会用石灰改性以提高强度。在这项研究中，石灰改性土壤（LMS）试样经受冻融循环，通过弹性模量测试和扫描电镜测试研究了试样的力学性能和微观结构。通过图像分析研究孔隙微观结构的变化。结果表明，由于冻融循环下土壤中水的相变和膨胀，微孔的数量和面积减少，随后微孔合并为大孔。孔隙率和弹性模量的变化是相关的。在第一次冻融循环后观察到对 LMS 的微观结构和弹性模量的最大影响。