Relationship between Methylene Blue Value, Initial Soil Suction and Swell Percent of Expansive Soils


Abstract: The purpose of this study was to investigate the relationship between methylene blue value, initial soil suction and the swell percentage of expansive soil samples. In this study, commercially processed kaolinite and bentonite mineral clays were mixed in preselected proportions to obtain soil samples possessing a wide range of plasticities and different swell percentages. The methylene blue adsorption tests, suction measurements using a thermocouple psychrometer technique and standard free swell tests in oedometer cells (ASTM D4546-90) were conducted on samples of kaolinite-bentonite mixtures. The results indicated a linear relationship between methylene blue value and swell percent and also between initial soil suction (Log) and swell percent. The experimental relationship which directly relates the methylene blue value and initial soil suction to the swell percent is established, the reliability of the swell percent prediction method based on methylene blue value and initial soil suction (Log_{10}) data is evaluated, and the coefficient of correlation (R^{2}) of this relationship is 0.992.

Keywords: Expansive soil, Methylene blue value, Psychrometer, Swell percent, Soil suction.

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