ELECTROKINETIC PHENOMENA OF CATION EXCHANGE AND ITS EFFECT ON THE BEHAVIOUR OF EXPANSIVE CLAYS

Abstract

This research is a series study of electrokinetic process that used as an alternative of stabilization
effort of expansive clays. In particular, an observation of the behavioral changes of soil properties and also
behavioral changes of soil swell that occur due to the phenomenon of cation exchange during the electrokinatic
process were conducted. The cation used in this study was calcium ions (Ca2+) which are derived from the
solution of lime which also used as a stabilizer. Electrokinetic test was conducted by using 2A and 25V DC
power. The tested samples in this study were taken from three different locations in Central Java, namely:
Purwodadi, Boyolali and Klaten. The composition and concentration of ions in expansive clays was tested by
using AAS (Atomic Absorption Spectrum) method. Behavioral of soil properties known the limits of Atterberg
(ASTM 4318 and ASTM 427) from testing while the swelling behavior of soil by testing of swelling (ASTM
4546). The observations against the behavior of clay expansive was at the condition of a change in the
concentration of sodium ions (Na+
) in the soil during the electrokinetic process. The results showed that at
conditions of the concentration of sodium ions (Na+
) was smaller than the initial concentration, the behavior
of the value of the liquid limit (LL), the index plastic (PI) and the nature of the development of clay expansive
indicated a downward trend, while the behavior of the boundary value shrinkage of the soil showed an upward
trend. The results of this research can be used as a baseline data to the development of electrokinetic as an
alternative effort of stabilization expansive clays.