Vol16 No.6: 1470-1482
【Title】Microstructure and strength features of warm and ice-rich frozen soil treated with high-performance cements
【Author】SUN Gao-chen1,2,3; ZHANG Jian-ming1*; DANG Ying-sheng4; DING Cong5
【Addresses】1 State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; 2 University of Chinese Academy of Sciences, Beijing 10049, China; 3 China State Construction Engineering Corporation Aecom Consultant Co., Ltd., Lanzhou 730000, China; 4 College of Water & Architectural Engineering, Shihezi University, Shihezi 832000, China; 5 Shanghai Investigation, Design & Research Institute Co., Ltd., Shanghai 200434, China
【Corresponding author】ZHANG Jian-ming
【Citation】Sun GC, Zhang JM, Dang YS, et al. (2019) Microstructure and strength features of warm and ice-rich frozen soil treated with high-performance cements. Journal of Mountain Science 16(6). https://doi.org/10.1007/s11629-018-5197-6
【Abstract】Warm and ice-rich frozen soil (WIRFS) exhibits lower shear strength due to the weak binding forces between soil particles and ice crystals. To enhance the strength of WIRFS, frozen soil was treated separately with Portland,Phosphate, Sulphoaluminate, Portland-Phosphate and Portland-Sulphoaluminate cements. After the samples were cured under -1.0°Cfor 7 days, the microscopic pore distribution characteristics and the macro-mechanical properties of WIRFS were investigated using mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM) and unconfined compressive strength (UCS) tests. To quantitatively analyze the laws of pore-size transformation and the variation of Hausdorff volumetric fractal dimensions for pre-and post-treated WIRFS, the CURVEEXTRACT and Image-Pro Plus (IPP) image analysis system has been developed for analysing SEM images of the soil samples. Statistics of the pore-area dimension and pore-volume dimension were calculated. The results reveal that the cement-based treatment of WIRFS can improve the cementation fill of soil pores and the bond forces between soil particles. There is an evident correlation between the microstructure characteristics and the mechanical properties of the treated WIRFS. As the fractal dimensions of pore-area decrease, the unconfined compressive strength of cement-treated WIRFS increases significantly. In contrast, as the fractal dimensions of pore-volume increases, the unconfined compressive strength decreases remarkably.
【Keywords】Soil stabilizer; Frozen soil; Microstructure characteristics; Macro-mechanical properties; Fractal theory; Scanning electron microscopy