Gel Formation at the Front of Expanding Calcium Bentonites

The removal of potentially harmful radioactive waste from the anthroposphere will require disposal in geological repositories, designs which often favour inclusion a clay backfill or engineered barrier around waste. Bentonite is proposed as this and understanding its long-term performance behaviour vital establishing safety case for usage. There are many different compositions bentonite that exist much research has focussed on properties both sodium (Na) calcium (Ca) bentonites. This study focusses results swelling test Bulgarian Ca showed an unusual gel formation at expanding front, unobserved previous tests type using MX80. was able to swell completely fill internal void space over duration test, with thin layer present one end sample. gel, along rest bulk sample, have been investigated ESEM, EXDA XRD analyses mechanism attributed migration nanoparticulate smectite through more silica-rich matrix substrate. out sample important implications erosion where interacts flowing groundwater repository host rocks.