抄録
Cation-fixation in soil occurs when exchangeable or water-soluble cation in soil are converted into the form that cannot be readily extracted with a solution of neutral salt. That is, exchangeable ions are changed to the nonreplaceable state.
Potassium ions are known to be the primary one involved in such a reaction. In the field of pedology, the study of K-fixation has been performed actively, but from the viewpoint of soil mechanics, especially soil stabilization, it has been hardly done. The present study was undertaken to clarify the physicd-chemical change of clay minerals and the change of the engineering properties due to K-fixation.
From the results of X-ray diffraction and differential thermal analysis, it was found that K-fixed soil has a structure similar to illitic clay. The engineering properties of montmorillonite is also stabilized. It is considered that this stabilization is due to the formation of aggregate of clay caused by the decrease in potential energy between clay particles and by the fixation of K ions between the internal layers of clay.
