As a result of studies conducted on black cotton soils (which is predominantly montmorillonite), it has been shown that plasticity index starts falling as the soil is heated beyond 250 degrees C and at a temperature of about 450 degrees C the soil becomes completely non plastic. In actual practice however, it may not be possible to pulverise black cotton soil effectively, with the result that soil will always be found mixed up with a large percentage of clods of varying sizes. The laboratory studies conducted on heat treatment of clods alone, has shown that an optimim temperature between 500 degrees C and 600 degrees C is required to impart maximum strength to the burnt clods. A temperature of 600 degrees C will not only make the powdered soil non-plastic, but will also make the aggregates fairly strong. A laboratory study in India has shown, that on account of comparatively low temperature of heating required for black cotton soil as aginst other plastic soils, it should be economical to improve the soils in the field by heat treatment. The analysis of the burnt material from various lengths using clods of different sizes at increasing moisture contents, and burnt at increasing rates, for aggregate impact values showed that the strength of the burnt aggregate of a particular size and moisture content decreases both in the dry and wet conditions as the speed of burning machine increases. It futher appears that strength falls with increase in the size of the clod as well as the moisture content, for a fixed speed of the burning machine.

  • Corporate Authors:

    Indian Roads Congress

    Jamnagar House, Shahjahan Road
    New Delhi,   India  110 011
  • Authors:
    • Uppal, H L
  • Publication Date: 1965-9

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Filing Info

  • Accession Number: 00263502
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 13 1974 12:00AM