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Zinc tailing waste material is generated during the extraction of zinc metal. Its deposit is increasing year after year posing a threat to the environment and occupying large precious land. The present research explores the possibility of its application in road construction and filling. Physical and chemical tests were carried out, viz. SEM, EDS, X-ray diffraction and toxicity characteristics leachate procedure. The geotechnical characterisation was carried out and compared with similar types of materials, viz. soil and industrial wastes (fly ash and jarofix). Stress-settlement behaviour was studied by using a small scale physical model and validated by a numerical model test. Tailing was further mixed with cement to improve its properties for application in stabilised layers. Tailing is a porous, multi-phase and non-swelling cohesionless fine-grained material. It contains mainly oxides of silica, alumina, magnesium, calcium and less concentration of heavy metals. It has a high dry density (18.62 kN/m3), California Bearing Ratio (11%) and angle of internal friction (34°) compared to soil which makes it suitable for road construction. Cement stabilised tailing can be used in sub-base layer and can save about 170 mm thickness of the aggregate layer. Modulus value (18.17 MPa) indicates that it is a stiff material which leads to less settlement as a structural fill. [ABSTRACT FROM AUTHOR]

Jarofix is a waste material generated during the extraction of zinc from its ore. Laboratory characterisation of stabilised jarofix was carried out to investigate the feasibility of its utilisation in embankment and granular layers of road construction. It was stabilised by the addition of soil in the range of 25-75% and cement in the range of 3-9%. Stress-displacement behaviour of jarofix-soil mixes was studied by conducting a series of direct shear tests at different dry densities and normal stresses. Different geotechnical parameters of jarofix-soil mixes, namely, shear stress ratio, peak and critical friction angles, and dilation were studied. For 50% soil content in the jarofix-soil mix, the values of peak friction angle increase in the range of 5-15% and maximum dry density in the range of 10-20%. In addition to this, tensile modulus and shear strength parameters of cement-stabilised jarofix were determined. The addition of cement improves the modulus and shear strength parameters, which makes it suitable for the application in steep slope embankments and subbase/base layers of road construction. Cement-stabilised jarofix material can effectively reduce the thickness of subbase and base layers of a flexible pavement approximately by 20%, and lead to economical and sustainable road construction. [ABSTRACT FROM AUTHOR]

An experimental program was undertaken to study the individual and combined effects of randomly oriented fiber inclusions and cement stabilization on the geotechnical characteristics of fly ash-soil mixtures. An Indian fly ash was mixed with silt and sand in different proportions. The geotechnical characteristics of the raw fly ash-soil specimens and fly ash-soil specimens containing 1% randomly oriented polyester fiber inclusions were investigated. Unconfined compression tests were carried out on fly ash-soil specimens prepared with 3% cement content alone and also with 3% cement and 1% fiber contents, after different periods of curing. The study shows that cement stabilization increases the strength of the raw fly ash-soil specimens. The fiber inclusions increase the strength of the raw fly ash-soil specimens as well as that of the cement-stabilized specimens and change their brittle behavior to ductile behavior. Depending on the type of fly ash-soil mixture and curing period, the increase in strength caused by the combined action of cement and fibers is either more than or nearly equal to the sum of the increase caused by them individually.