CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING



AbstractIn this study, the aim has been to investigate the efficacy of Indian marble dust–bentonite (MD–B) subjected to electrolyte concentrations (NaCl, NaOH, and HCl) to be used as an alternative to sand–bentonite (S–B) mixes in landfill liner. The major concern of the engineered landfill liner design is to retard the migration of hazardous leachate solutions into the groundwater. Geotechnical properties, such as plasticity index, compaction characteristics, permeability, and swelling percentage, are the most important criteria to be examined for any landfill liner materials permeated with electrolyte concentrations. Hence, this study evaluates the behavior of both MD–B and S–B mixes subjected to varying concentrations of salt (i.e., NaCl of 0.1, 0.5, and 1 N), alkaline (i.e., NaOH of 1, 1.5, and 2 N), and acidic (i.e., HCl of 1, 1.5, and 2 N) solutions. The results reveal that the behaviors of MD–B and S–B mixes are similar, subjected to various concentrations of NaCl, NaOH, and HCl solutions. It has been confirmed that MD–B is a suitable alternative to S–B mixes even under different physicochemical conditions. However, marble dust and sand need to be incorporated with at least 40% and 60% bentonite to encounter the desired effect of electrolyte concentration for maintaining the coefficient of permeability (<10−7 cm/s) and other parameters, such as plasticity and swelling characteristics, when used as a landfill liner material. Physicochemical analyses [pH and electrical conductivity (EC)] and microanalyses [X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDAX)] were also performed. The cost effectiveness of marble dust for large-scale utilization is also discussed.


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