This study focused on the drying behavior of compacted bentonite-sand mixtures which are among the materials proposed to be used as landfill liners or landfill covers in many countries. Mixtures of a bentonite, Calcigel, and quartz sand were used at two different compaction conditions, namely, dry of optimum (DOP) and wet of optimum (WOP). The mixtures used had compositions of 30%-70% and 50%-50% bentonite-sand mixtures and pure bentonite. Mercury intrusion porosimetry (MIP) and Environmental scanning electron microscopy (ESEM) studies were also performed to investigate the micro fabric of the specimens. It is found that the pore size distribution (PSD) of the specimens show bi-modal characteristics indicating the presence of micro- and macro-pores. The pure bentonite specimens exhibit the greater shrinkage upon drying regardless the compaction conditions. Bentonite void ratio of specimen after complete drying decreases with increasing bentonite content. Considering permeability and shear strength aspects, for these mixtures, it is recommended to use 50% bentonite content (dry mass basis) for landfill applications.
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