A cids as chemical stabilizers of clay soils

Summary

1. In the acid stabilization of clay soils the aluminosilicate nucleus of the clay minerals is attacked. This process is accompanied by the escape of primarily the aluminum ion from the crystal lattice and the formation of depolymerized silicic acid. As the acid medium is neutralized to pH>3, the latter is condensed into an acid, highly hydrated silica gel, which cements the soil.

2. The aluminum and, to a lesser extent, iron, calcium, and magnesium salts formed as a result of exchange reactions play a secondary role in the chemical stabilization process.

3. Fluosilicic and phosphoric acids are most effective for treating clay soils. However, treatment with acids does not achieve the long-term stabilization of the surface horizons of soils subject to periodic freezing and thawing or wetting and drying out. Soils stabilized with phosphoric acid are biologically unstable.

4. A serious disadvantage of the acid stabilization of clay soils is the technical difficulties associated with the need to mix acid with the soil and the impossibility of its injection into practically impermeable soils. This is an obstacle to the use of acid stabilization in foundation building.