Volume 9, Issue 4 (December 1986)

    A Rapid Method to Identify Clay Type in Soils By the Free-Swell Technique

    CODEN: GTJOAD

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    Abstract

    This paper reports a rapid method to identify the presence of nonswelling clay, swelling clay, or a mixture of the two types of clays in a soil from the sediment volumes occupied by 10 g of dry soil in 100 mL of water and carbon tetrachloride, respectively, under no external constraint. Soils that occupy a sediment volume of < 1.50 m3/Mg in water and 1.10 to 3.00 m3/Mg in carbon tetrachloride contain nonswelling clay. Soils that occupy sediment volume of ≤ 1.10 m3/Mg in carbon tetrachloride and a volume ≥ 1.50 m3/Mg in water contain swelling clay. Soils that occupy sediment volumes > 1.10 m3/Mg in carbon tetrachloride and volumes ≥ 1.50 m3/Mg in water contain both nonswelling and swelling clays. The results agree well with X-ray diffraction and infrared analysis.

    In the latter part of the work, the limitations in the existing definition of the free-swell index of soils is brought out. The present definition gives a negative free-swell value for soils containing nonswelling clay and a reduced value for soils containing a mixture of nonswelling and swelling clays. The free-swell index of soils is defined as the sediment volume occupied by 10 g of dry soil in 100 mL of water under no external constraint and expressed in units of m3/Mg. Further, the sediment volume of a soil (10 g) in a nonpolar solvent, is utilized to give information on the clay type present in the soil, namely, nonswelling, swelling, or a combination of both. A classification for identifying a soil's expansivity based on the new definition of the free-swell index and the clay mineralogical composition of the soils is given.


    Author Information:

    Sridharan, A
    Professor, research scientist, and research student, Indian Institute of Science, Bangalore,

    Rao, SM
    Professor, research scientist, and research student, Indian Institute of Science, Bangalore,

    Murthy, NS
    Professor, research scientist, and research student, Indian Institute of Science, Bangalore,


    Stock #: GTJ10630J

    ISSN: 0149-6115

    DOI: 10.1520/GTJ10630J

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    Author
    Title A Rapid Method to Identify Clay Type in Soils By the Free-Swell Technique
    Symposium , 0000-00-00
    Committee D18