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

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