Influence of 2‐hydroxypropyltrimethyl ammonium chloride chitosan on sedimentation and volume change behavior of cohesive soil sediments

The 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC), introducing the functional quaternary ammonium group to the structure of Chitosan, has greatly broadened the application prospect. The influence on natural cohesive soil has rarely been considered. The sedimentation tests for the natural soil in HACC solutions and the HACC-treated soils in distilled water are considered to analyze the change of sedimentation behaviors in this paper. Moreover, the potential change on the surface of soil particles, the change in particle size distribution, X-ray diffraction of Ca-montmorillonite/HACC, and scanning electron microscopy images are investigated to explain the reasons for the results. Results indicate that the surface potential of soil particles achieved reversal, and the particle size had significant agglomeration. The adsorption of HACC results in the rapid sedimentation of the treated soils in water. HACC has a significant influence on setting time and final volume. HACC cannot inhibit the interlayer swelling of Ca-montmorillonite. The dehydration process can promote the aggregation effect of the treated soils. The specific effects provided an essential train of thought to solve soil problems.