Liquid Limit of Montmorillonite Soils

Abstract The present work investigates the influence of compositional factors on the liquid limit of montmorillonite soils. The results showed that the percent clay fraction and surface area values did not relate with the liquid limit of the soils; the latter, however, were essentially controlled by the diffuse double layer thickness. Examination of the relations between compositional factors that affect the double layer thickness and liquid limit showed that the latter did not have a significant bearing with cation exchange capacity, while a near perfect correlation was obtained with the amount of exchangeable sodium ions present. Such a dependence resulted because of the greater ease of dissociation of adsorbed sodium ions from the clay surface in presence of water and subsequent contribution to the double layer thickness; the other exchangeable cations, namely, calcium, magnesium, and potassium, were strongly adsorbed by the clay surface and did not contribute appreciably to the double layer thickness.