Effect of soluble gypsum on swell behaviour of lime-treated expansive soil – a micro-level investigation

ABSTRACT

Lime treatment of soil is a widely adopted technique to improve its properties. However, the durability of lime-treated soil under varying environmental conditions such as contamination with chemical agents is still a matter of concern. An attempt has been made to examine the swelling behaviour of untreated and lime-treated expansive soil subjected to sulphate contamination (i.e. soluble gypsum). Series of the free swell index and one-dimensional oedometer swell tests have been performed in untreated and lime-treated soil inundating with soluble gypsum of varying sulphate concentration (i.e. low to high; 0 to 30000 ppm). The results of one-dimensional oedometer swell tests revealed that the sulphate contamination leads to the reduction in the maximum swelling percentage of untreated soil. On contrary, a drastic increase in the swelling percentage has been observed in the lime-treated soil subjected to contamination up to 16000 ppm, which diminishes thereafter with an increase in sulphate concentration. It is revealed that the sulphate contamination has observed promising effect on untreated soil; whereas a susceptible behaviour is pronounced in the lime-treated soil up to 16000 ppm sulphate concentration. Further, experimental outcomes are elucidated based on the detailed microanalyses (XRD, SEM, EDAX and FTIR) of samples.

KEYWORDS:

• Contamination
• lime
• microanalysis
• swell
• sulphate

Acknowledgments

Authors acknowledge the Research and Development (R & D) division of Manipal University Jaipur (MUJ) for providing financial support under Intra-Mural grant [Project Number: MUJ/REGR1435/07]. Further, authors would like to thanks to reviewer/editor for their critical comments/remarks which help to improve the quality of the paper.

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No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Manipal University [MUJ/REGR1435/07].