A comparison between acetone and dioxane and explanation of their role in water replacement in undisturbed soil samples

Abstract

SUMMARYUndisturbed, moist samples from the A horizon of a swelling grey clay were treated with acetone or dioxane with or without para‐dichlorobenzene to replace soil water. They were then either impregnated with polyester resin whilst still solvent‐wet or after drying. Structural changes in samples treated with dioxane and then impregnated while solvent‐wet indicated little evidence of either disintegration or shrinkage resulting from the treatment. However, samples treated with acetone were prone to disintegration, but this was mitigated somewhat by the addition of para‐dichlorobenzene. Allowing either solvent to evaporate before impregnation caused shrinkage.X‐ray diffraction and infra‐red studies of treated clay separates indicated that dioxane prevented the marked swelling and potential dispersion found with acetone. It was concluded that dioxane breaks structural bonds within clay interlayers and between soil crumbs, thus limiting both collapse of clay minerals and sample shrinkage on drying. No changes to plasmic fabrics could be seen under a petrological microscope. Because of their appropriate size and shape, dioxane molecules could also enter clay interlayers so preventing marked shrink/swell movements. There is some indication that they may also form epoxide‐like compounds that themselves form structural ‘cements’.