Mineralogical changes and geotechnical properties of an expansive soil interacted with caustic solution

Sivapullaiah, Puvvadi Venkata and Sankara, Gullapalli and Allam, Mehter M (2010) Mineralogical changes and geotechnical properties of an expansive soil interacted with caustic solution. In: Environmental Earth Sciences, 60 (6). pp. 1189-1199.

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Abstract

The type and amount of clay mineral plays an important role in the behaviour of fine-grained soils. Clay minerals are the primary source and moisture is often the external agent of swelling in soils. Also soils may exhibit increased/reduced swelling due to interaction with chemicals. Alkalis used in industrial operations are one such example. Concentrations of alkali and mineral type are the key factors in such interactions. The present paper reports the changes in the properties of an expansive Black Cotton soil containing a mixed layer mineral, rectorite upon interaction with high concentration caustic solutions. X-ray diffraction studies have shown that the rectorite present in the soil undergoes changes with increase in the concentration of alkali. Saponite gets transformed to nantronite. Small amount of kaolinitic mineral present in the soil also reacts with alkali producing some changes in its mineralogy. Many hydroxides are produced. Differential thermal analysis studies have been supportive of these changes. Consequent of these changes, the soil-specific surface increases, changes its Atterberg limits and free swell volume increases. The results have been supported by the characteristics and behaviour of samples contaminated in the field with alkali from an alumina extraction plant.

Item Type:	Journal Article
Publication:	Environmental Earth Sciences
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Alkali;Atterberg limits;DTA;Index properties;Rectorite;X-ray diffraction
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	02 Jun 2010 05:25
Last Modified:	02 Nov 2011 06:23
URI:	http://eprints.iisc.ac.in/id/eprint/27718

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