Effect of inorganic salt solutions on consistency limits of kaolinite

Abstract

This study presents the effect of different inorganic salt solutions
 (KCl, BaCl2, MgCl2, KNO3, Na2SO4
 and MgSO4) at different concentrations on geotechnical properties
 (Atterberg Limits) of kaolinite material which can be used as impermeable
 bottom liner in barrier systems. Since the use of distilled water or tap water
 is far from being representative of the in-situ conditions in landfills, salt
 solutions were used to investigate the leachate effect on liner materials.
 Additionally, the mineralogical characterization of kaolinite was studied.  Atterberg limits, specifically the liquid
 limit (LL) and plastic limit (PL) that were used for classifying the clayey
 soil samples according to the Unified Soil Classification System were
 determined whereas mineralogical studies performed included XRD, BET and FT-IR
 analyses. Results indicated that all salt solutions have a considerable effect
 on the consistency limits of kaolinite. The liquid limit values of kaolinite
 decreased with increasing chemical concentration whereas plastic limit values
 increased. It is observed that the effects of the divalent and trivalent
 cations on kaolinite were more apparent than those of monovalent cations. As a
 result chemical solutions decrease liquid limit values of high plasticity
 kaolinite materials,  tend to reduce the
 thickness of the DDL and flocculate the kaolinite particles, resulting in
 reduction of swelling and increasing of hydraulic conductivity.