Effects of Mixing of Bentonite Suspension in Geotechnical Applications-Paper

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Bentonite suspensions are widely used to stabilize pile borings and excavation trenches, and, when combined with cement, to produce grouts and self-hardening cut-off wall mixtures. Their performance depends on properties such as viscosity, density, gel strength and bleeding, which are influenced by bentonite concentration, water quality, mixing energy, hydration time, temperature and additives.<br /><br />Effective preparation requires thorough wetting, dispersion and homogenization. High-shear mixing, fluid circulation and continued agitation promote hydration and help develop the viscosity and gel strength needed for excavation stability. The paper recommends storing mixed slurry for at least 12 hours before use; hydration continues over time, with properties approaching stable values over several days. Remixing can further improve gel strength.<br /><br />Bentonite concentration must be selected for the application and ground conditions. Typical suspensions contain 3–5% bentonite by weight, though insufficient concentration or hydration may lead to bleeding and instability. Excessive viscosity, however, can hinder pumping, de-sanding and removal of suspended soil. Field and laboratory results also indicate that mixing method affects bleeding, while bentonite content and admixtures influence viscosity and other properties in bentonite-cement grout.<br /><br />The authors emphasize monitoring pH, density, viscosity, sand content and filtration characteristics throughout preparation and construction. Overall, reliable performance depends on appropriate proportions, high-shear mixing, adequate hydration and suitable additives. These controls help produce stable support fluids and grouts while supporting efficient construction.

Keywords

bentonite suspension

pile boring stabilization

excavation trench support

bentonite-cement grout

self-hardening cut-off wall

viscosity

gel strength

hydration time

high-shear mixing

bleeding control