This paper examines the efficiency of in-situ stabilization of expansive soil by lime slurry technique in desiccated state through laboratory and field experimental studies. The laboratory and field studies consists of permeating 34% hydrated lime slurry into the desiccated soil through vertical holes and measuring the physico-chemical, index and engineering properties before and after treatment at different radial distances. The distinct changes in the physico-chemical and index properties of the expansive soil indicate the occurrence of lime modification reactions and pozzolanic reactions on lime migration into the inter-connected shrinkage cracks. The lime slurry treatment increased the soil pH (≈ 12) to the levels that are conducive for the pozzolanic reactions to occur. The soil-lime reactions reduced the swelling potential and increased the unconfined compressive strength of lime slurry treated expansive soil. The test results encourage the application of lime slurry technique to expansive soil deposits during dry season upon development of shrinkage cracks.. J. Ross Publishing, Inc. © 2012

T. Thyagaraj

Department Of Civil Engineering

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

In-situ stabilization of an expansive soil in desiccated state

International Journal of Geotechnical Engineering

Lime stabilization is an age-old technique for controlling the swell-shrink characteristics of the expansive soil. However, the presence of sulphate in the expansive soils renders the lime stabilization ineffective due to the formation of detrimental compounds–ettringite and thaumasite. The formation of these detrimental compounds can be counteracted by treatment with low-calcium or non-calcium based stabilizers. However, there is a possibility of sulphate contamination post lime stabilization through external sources. Therefore, the present study brings out the effect of short-term sulphate contamination on lime-stabilized expansive soil using sodium sulphate solution. To achieve this objective, the lime-stabilized expansive soil was cured for 1, 7 and 28 days, and subsequently mixed with sulphate solutions of 5000–20,000 ppm concentration and allowed to equilibrate for 1 day. The experimental results showed that the sulphate contamination had a significant effect on the soil structure, physico-chemical and index properties of lime-stabilized soil. The mechanism governing the deterioration of the stabilized soil depended on the curing period of lime-stabilized soil prior to contamination with sulphate. Short-term sulphate contamination of lime-stabilized soil cured for 1 and 7 days resulted in highly flocculated structure, whereas the lime-stabilized soil cured for 28 days resulted in the formation of ettringite. This is evidenced with the aid of Scanning Electron Microscopy (SEM) images, X-ray diffraction (XRD) and Energy Dispersive X-Ray Analysis (EDAX). It can be concluded from this study that the ettringite formation occurs even after the formation of pozzolanic compounds in lime-stabilized soil. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.

Effect of short-term sulphate contamination on lime-stabilized expansive soil

Sequential permeation of calcium chloride and sodium hydroxide solutions into the soil mass leads to the formation of lime in the in-situ soil mass owing to chemical reactions. Previous studies have demonstrated that the lime precipitation modifies the expansive soil properties both by lime modification and pozzolanic reactions. However, the independent contributions of either calcium chloride solution or sodium hydroxide solution in stabilizing the expansive soil are not known. Therefore, an attempt is made in the present investigation to examine the relative efficiencies of calcium chloride solution, sodium hydroxide solution and lime precipitation in stabilizing the expansive soil by comparing the physico-chemical and index properties, oedometer swell potentials and unconfined compressive strength of treated specimens. The present investigation also brings out the relative efficiencies of hydrated lime and precipitated lime in stabilizing the expansive soil. The experimental results showed that treating the expansive soils with calcium chloride and sodium hydroxide solutions independently promoted only the short-term reactions whereas the sequentially treating the expansive soil with calcium chloride and sodium hydroxide solutions resulted in the formation of lime precipitation, which could mobilize both short-term lime-modification reactions and long-term soil-lime pozzolanic reactions. © 2016 Taylor & Francis.

Relative efficiencies of electrolytes in stabilization of an expansive soil

The necessity to tap natural marine resources from the ocean beds represents a considerable challenge for the construction of offshore structures on weak marine deposits. The use of lime to improve the behaviour of soft clays is not new. The present investigation examines lime-induced changes in the compressibility of marine clay. The test results indicate a reduction of 1/2 to 1/3 in the compressibility of the soil system within 30 to 45 days of treatment. The formation of various cementation compounds due to soil-lime reactions improves the soil characteristics with time. The results encourage the application of lime column and lime injection techniques to improve the engineering behaviour of soft marine clayey deposits. However, one has to be cautious in applying the lime technique to marine clays that contain sodium sulfate. © 2002 Published by Elsevier Science Ltd.

Journal	International Journal of Geotechnical Engineering
Publisher	Maney Publishing
ISSN	19386362
Open Access	No