Study on strength characteristics and mechanism of loess stabilized by F1 ionic soil stabilizer

Ionic soil stabilization additives can improve soil compactness and strength rapidly and efficiently by chemical reaction. In order to study the stabilization mechanism of the F1 ionic soil stabilization additive and the basic engineering properties of the stabilized soil, the basic physical parameters, CBR value, unconfined compressive strength, expansion characteristics, and microscopic pore structure characteristics of the loess before and after F1 stabilization were studied by using micro and macro testing methods. The results show that the high-energy H3O+ of F1 dissociated with water can exchange with the metal cation and polar water molecule on the surface of clay particles, and neutralize the vacancy anion, so that the charged property, ion type, and concentration on the surface of stabilized soil particles can change. In F1, the sulfonated oil-coated soil particles form a hydrophobic oily layer, which reduces the plastic limit and optimal water content of the soil, increases the plastic index, and reduces the water sensitivity. The F1, through a series of physical and chemical effects, reduces the clay minerals’ surface electric potential and the electric double layer thickness of the water film; changes the pore structure and the form of contact between the soil particles; causes the soil particles through fine flocculation to join together into large particles; reduces the soil micro-pore area, the total number of pores, and the pore distribution fractal dimension, inhibiting the expansion deformation of the soil; increases the connection strength between the soil particles, the maximum dry density, and the CBR value; and makes the arrangement closer; a layer-stacked structure with more compact arrangement, larger aggregates, and surface-to-surface contact was formed under the action of compaction. F1 has many advantages that traditional soil stabilization additives do not have and has a broad application potential in soil reinforcement engineering in loess areas.