Effects of Organic Liquids on the Permeability of Selma Chalk

Abstract

ABSTRACT

The permeability of monolithic specimens of Selma chalk to six pure organic liquids - acetone, ethylene glycol, heptane, acetic acid, xylene, and aniline - representing some of the classes of organic compounds stored in hazardous waste repositories and to water, was measured in the laboratory. Specimens were core-drilled from large blocks of chalk obtained from the formation in western Alabama and in central Alabama, 150 km to the cast. Specimens of both "virgin chalk" and of chalk taken from naturally re-cemented crack zones were studied. In order to prevent viscosity effects from masking the changes in chalk structure brought on by contact with the permeant, intrinsic permeabilities rather than hydraulic conductivities are reported. Compared to data for water (intrinsic permeability of 1.5 × 10⁻¹³ cm²) the mean values of the experimentally measured permeabilities to the organic liquids were found to be higher, but not by more than a factor of ten. The only exception was the permeability to ethylene glycol, which had a mean value about thirty times that to water. Higher mean values were significant at the 90% level of confidence only for ethylene glycol and aniline. There was not much difference found in permeability between specimens from the western and central Alabama locations or between "virgin chalk" and chalk taken from re-cemented crack zones.