Abstract
The expansion-collapse characteristics of rectorites are investigated by X-raydiffraction under conditions of relative humidities, ethylene glycol and glycerol treatments and Greene-Kelly test. The expandability of rectorites is similar to that of beidellite rather than montmorillonite. The distinctive nature is shown under the conditions of 30-90% relative humidity (Na-and Ba-form), ethylene glycol treatment (K-form) and Greene-Kelly test. The difference of expandability between montmorillonite and beidellite is not observed on glycerol treatment (Mg-form). The expandabilities of the minerals are somewhat different from sample to sample. The relationships between chemical compositions and expansion characteristics are discussed.
