Improvement of loess characteristics using sodium alginate

Loess often has poor engineering properties due to its loose accumulation and strong collapsibility. Therefore, improvement of the soil is necessary to meet the needs of engineering. In the current work, the improvement effect of sodium alginate added in different proportions to loess was studied. Limited water content test and particle size grading test were conducted to study the effect of sodium alginate on the basic physical parameters of soil. In addition, unconfined compressive strength test (UCS) and consolidated undrained test (CU) were used to analyze the changes in the mechanical properties of the soil after improvement. Additionally, permeation and disintegration tests were used to study the change in the soil's water stability. What's more, the microscopic mechanism of sodium alginate improved loess was also proposed based on the results of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that sodium alginate not only can change the liquid-plastic limit and particle size gradation of loess but also improve the strength, shear parameters, and water stability of loess. SEM and XRD studies revealed that sodium alginate changed the microstructure of the loess, formed a colloidal material to encapsulate the soil particles, filled the pores between soil particles, and caused aggregation of the clay material in the soil to form larger particle size via flocculation. These results show that sodium alginate can be used as a more environmental friendly and sustainable additive to replace the traditional soil stabilization additives, such as cement or lime to stabilize loess.