Reversibility of swell behaviour of bentomte inundated with liquids

Compacted bentonite soils are commonly used as liner, filling, and capping materials. However; in geoenvironmental applications, the bentonite is exposed to alternating pore fluid composition. The aim of this paper is to investigate these phenomena and their reversible and irreversible effects on the swell behaviour. Specimens of bentonite were alternatively exposed to distilled water, 1x\0 3 , ΚΝ0 3 , Ca(10 3 ) 2 or Cd(10 3 ) 3 solutions (1 N) in pedometer tests. Exposure to any of the four electrolytes significantly altered the swell behaviour of the bentonite specimens under 7 kPa normal pressure. Nab 3 effects amplified the swell potential of specimens when re-exposed to water. ΚN0 3 effects were reversible and no K fixation was observed under the employed testing procedure. Ca(11 3 ) 2 and Cd(10 3 ) 3 effects persisted only under certain conditions. The effects of these electrolytes can be reversed through subsequent exposure of the specimens to NaiO 3 solution then to water.