ISSN: 0149-6115
Published Online: 24 June 2008
Page Count: 10

Methylene Blue Surface Area Method to Correlate with Specific Soil Properties

Sivapullaiah, P. V.
Professor,Department of Civil Engineering, Indian Institute of Science,

Prasad, B. Guru
Research Scholar,Department of Civil Engineering, Indian Institute of Science,

Allam, M. M.
Professor,Department of Civil Engineering, Indian Institute of Science,

(Received 5 September 2007; accepted 16 May 2008)

Abstract

Specific surface area (SSA) of soils is calculated by determining the amount of adsorbed substance such as methylene blue (MB), ethylene glycol monoehtyl ether (EGME), or water required to form a monolayer. Free swell index and liquid limit of soils, which are well correlated with each other, and with engineering properties of soils, can be used to check the relative advantage of determination of a specific area by different methods in geotechnical engineering. The water adsorption method yields different values depending on the relative humidity (RH) at which the soils are equilibrated with water and gives significantly high adsorption values at 100 % RH. The water adsorption method, comparatively simpler, gives more accurate values for kaolinitc soils but generally has lower values for soils with montmorillonitic mineral owing to insufficient saturation of exchangeable ions. The SSA values obtained by EMGE correlates reasonably well with free swell index. Improved correlation is observed in specific surface area values obtained by MB methods. The SSA values obtained by methylene blue titration (MBT) or as methylene blue spot method (MBS) are comparable.

Keywords:
methylene blue, ethylene glycol monoethyl ether, water adsorption, specific surface area, free swell index, liquid limit

Paper ID: GTJ101429
DOI: 10.1520/GTJ101429
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