Uma Shankar M

Department of Environmental and Water Resources Engineering

School of Civil Engineering

Vellore Campus

Phanikumar B.R.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Leachate studies on fly ash-stabilised expansive clay liners

Geomechanics and Geoengineering

This paper presents the use of sawdust (SD), an industrial waste blended with bentonite and Portland cement (PC) mixtures as a liner in a landfill, to minimize the migration of leachate contaminating the subsurface environment. An experimental programme has been evaluated to study the effect of SD content on the liquid limit (LL), free swell index (FSI), compaction, hydraulic conductivity and strength characteristics of blending with bentonite and PC mixtures. The deionized water (DIW) and diesel oil contaminant (DOC) were used as permeating fluids in the study. The LL, FSI, maximum dry density and strength of the mix blends decreased; on the other hand, the optimum moisture content and hydraulic conductivity increased with increase in SD content, respectively. On permeation of DOC for all the mix blends, lower hydraulic conductivity is obtained as compared to DIW. In addition to it, the UCS tests samples were examined for quantitative energy dispersive X-ray spectrometer at 0-, 14- and 28-day curing period. It reveals the increase in Ca/Si ratio and decrease in Al/Ca ratio resulted in the strength improvement with an increase in the curing period. Powdered X-ray diffraction analysis suggested the formation of the hydrated cementitious product in the mix blends. Based on the results obtained from the study, the optimum percentage of sawdust to be effectively used as liner to prevent groundwater contamination was found to be less than or equal to 20%.

Indian Geotechnical Journal

Use of Sawdust Blended with Bentonite and Cement Mixtures to Retain Diesel Oil Contaminants as a Liner in a Landfill

This paper presents the use of GGBS (ground granulated blast furnace slag) an industrial byproduct, blended with bentonite and Portland cement (PC) as a liner in a landfill to prevent groundwater contamination. Experimental investigations were conducted to study the effect of GGBS blended with bentonite and PC mixtures such as liquid limit (LL), free swell index (FSI), compaction, unconfined compressive strength (UCS) and hydraulic conductivity tests (k). Deionized water (DIW) and diesel oil contaminant (DOC) was used as permeating fluids in this study. DOC is an organic effluent from automobile industry which is a spillage/leakage contaminating ground water. The results obtained from the blends show that LL, FSI and k decreases, and optimum moisture content, maximum dry density and UCS (at 0, 14 and 28 days curing period) increased with increase in GGBS content. On examining the UCS samples by scanning electron microscope and X-ray diffraction, it reveals the formation of cementitious compounds which increases the strength. The k of the blends decreased with increase in GGBS content irrespective of permeating fluids. Leachability of heavy metals was also analyzed. Based on the results an optimum percentage of GGBS to be used as a liner should be in the range between 15% and 20%.

Journal of Environmental Chemical Engineering

Use of ground granulated blast furnace slag blended with bentonite and cement mixtures as a liner in a landfill to retain diesel oil contaminants

Journal of Cleaner Production

Correlation studies on geotechnical properties of various industrial byproducts generated from thermal power plants, iron and steel industries as liners in a landfill- a detailed review

The study of earthen barriers or clay liners has become very important in the field of geo-environmental engineering. The design of clay liners is based on the fact that leachate migration through clay liners depends on their hydraulic conductivity. The engineering behaviour of clay liners can be predicted through a proper estimation of some of the basic index properties like liquid limit which play a significant role in this study. An attempt at understanding the variation of index properties with the concentration of permeating fluids reveals useful facts about the clay liners. This paper proposes an innovative clay liner material in the form of fly ash-stabilised (or, fly ash-blended) expansive clay and presents a study on variation of index properties of the blend with varying fly ash content in the blend and concentration of salt solutions. The various permeating liquids used were deionised water and salt solutions such as CaCl2, NaCl and KCl. When expansive soils are stabilized with fly ash, index properties like liquid limit (LL) and swelling properties like free swell index (FSI) decrease; hydraulic conductivity also decreases because of a high dry density attained by the blend at increased fly ash contents. This paper presents experimental data on LL and FSI of an expansive clay soil stabilized with fly ash at 0%, 10%, 20% and 30% by weight of the expansive soil. The solution concentrations used in the test programme were 5 mM (or 5 milli Molar), 10 mM, 20 mM, 50 mM, 100 mM and 500 mM. LL and FSI decreased with increasing fly ash content in the blend and solution concentration for all the salt solutions. Useful correlations between LL and FSI for the salt solution concentration and the fly ash contents were obtained. Hydraulic conductivity decreased with increasing fly ash content in the blend and also with increasing solution concentration.

Correlation studies on index properties of fly ash-stabilised expansive clay liners

Geotextiles and Geomembranes

Hydraulic conductivity of geosynthetic clay liners to tailings impoundment solutions

Hydraulic conductivity of two geosynthetic clay liners permeated with a hyperalkaline solution

Bioresource Technology

Powdered activated carbon augmented activated sludge process for treatment of semi-aerobic landfill leachate using response surface methodology

Geotechnical and Geological Engineering

Geotechnical Properties of Low Calcium and High Calcium Fly Ash

Journal	Geomechanics and Geoengineering
Publisher	Informa UK Limited
ISSN	1748-6025
Open Access	0