Abstract:

The commonly used method to control and stabilize expansive soils is to add stabilizing agents, such as lime, fly ash or cement. Electrical resistivity of soil can be considered as a proxy for the spatial and temporal variability of many other soil physical properties. Because the method is non-destructive and very sensitive, it offers a very attractive tool for describing soil physical properties. The electrical resistivity of lime or fly ash treated expansive soils changes with the development of physicochemical process in the stabilized soils. The purpose of this work is to evaluate the potential application of electrical resistivity measurements for detecting the physicochemical process in lime or fly ash treated expansive soils. A series of experimental programs are performed to study the relationships among electrical resistivity, swell potential, swelling pressure, unconfined compressive strength during curing time. Four different zones named instantaneous reaction, principal reaction, residual reaction and steady phases are divided. A new, simple electrical resistivity method is put forward to evaluate the swell potential and shear strength of stabilizer-treated expansive soils. Its practical implication is validated by experiment results.

Key words: expansive soil, lime, fly ash, physicochemical reaction, electrical resistivity