Physical and Swell Behaviour of Sand–Bentonite and Marble Dust–Bentonite Mixes

Abstract

Numerous researches have been carried out on bentonite amended with soils (commonly sand) to form barriers material for waste disposal projects such as landfill, cores of earth dams and radioactive waste repository systems. However, the development of sustainable geo-materials is still a greater concern for geotechnical engineer. Bulk utilization of marble dust, produced in the Rajasthan, is a serious concern for safe environment. In the present study, an attempt has been made to modify the behaviour of marble dust with bentonite to develop a novel liner material for landfill system. Further, the behaviour of marble dust amended with bentonite has been compared with sand–bentonite mixture which is known to be used as a liner material. Atterberg’s limits, free swell index (FSI) and compaction characteristics (i.e. optimum water content and maximum dry density) of various proportion of both sand–bentonite and marble dust–bentonite mixtures (0:100–100:0) were determined. It is observed that MDD and OWC of sand reduce and, increase with an increase in its substitution with bentonite, respectively. The similar tendencies have been observed for marble dust–bentonite mixes. Further, the FSI of sand and marble dust is also observed to be increased drastically with its substitution with bentonite. The physicochemical examinations (pH and electrical conductivity (EC)) of entire mixes have been performed to elucidate the mechanism.