MICROSCOPIC MECHANISM OF SOLIDIFIED SILT WITH IONIC SOIL STABILIZER
WU Xueting1, XIANG Wei1,2, WANG Zhenhua1, ZHANG Meixia1
1. Faculty of Engineering, China University of Geosciences(Wuhan), Wuhan 430074;
2. Three Gorges Research Center for Geo-hazard, Ministry of Education, China University of Geosciences(Wuhan), Wuhan 430074
The typical silt in Wuhan is solidified with Ionic Soil Stabilizer(ISS). The plasticity index of soil with different mix proportions is obtained through the test of Atterberg limits. The compressive properties, microstructure, specific surface area, chemical composition, energy spectrum analysis and cation exchange test are carried out before and after the solidification of silt with ISS. The macroscopic and microscopic mechanism of the solidification of silt with ISS are studied. The test results show that the compressive strength of silt treated with ISS decreases and porosity decreases. Ionic Soil Stabilizer promotes aggregation and condensation of soil particles, aggregates obviously increase, specific surface area decreases, specific surface energy decreases, and soil structure is denser. There is no change in the chemical composition of the silt before and after solidification. Cation exchange reaction occurs between the ISS and the counter ion layer on the surface of the silt colloid particles. The K+ and Na+ ions in the diluents of the curing agent are captured and adsorbed by the silt. The Ca2+ and Mg2+ ions on the surface of clay particles are resolved, which makes the thickness of the diffusion layer thinner, the ξ potential decreased, and the clay colloid particles coalesced. ISS improves the strength and stability of the soil particles, so as to achieve the purpose of soil modification and solidification.