Experimental evidence of reduction in attractive and repulsive forces between clay particles permeated with organic liquids

Abstract

Researchers have investigated the engineering properties of clayey soils with organic fluids to evaluate the performance of earth structures affected by chemical spills or leachate. Reported results show that when the pore water of clayey soils was replaced with organic liquids, the engineering properties of clayey soils, such as hydraulic conductivity and stress–strain behavior, varied significantly and were similar to those of fine sand – silt. Variations in the engineering properties were mainly attributed to flocculation of particles due to decreases in the attractive and repulsive forces between the particles without showing any direct experimental evidence. In this study, flocculation of kaolinite and bentonite particles was investigated in the presence of water and organic liquids using an optical microscope (OM), and the first experimental evidence of soil flocculation due to pore fluid is presented. The OM results reveal that when the pore water of the soil is replaced with organic fluids, the soil particles flocculate and form a clustered structure with large pores within the flocs. The results also indicated that the degree of flocculation and the size of the formed cluster depend on the type of clay mineral and the characteristics of the organic liquid.Key words: clayey soils, organic liquids, engineering properties, attractive and repulsive forces, optical microscope.