Open AccessBentonite swelling characteristics with a hypersaline multi-component pore fluid
Author(s) -
R. W. I. Brachman,
R. Kerry Rowe,
A. Baral,
Mohamed Hosney,
Grant Su,
Thanh Son Nguyen,
Jerry Brown,
K. Lange
Publication year - 2021
Publication title -
canadian geotechnical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 118
eISSN - 1208-6010
pISSN - 0008-3674
DOI - 10.1139/cgj-2019-0558
Subject(s) - bentonite , swell , swelling , pore water pressure , potassium , sodium , chemistry , magnesium , mineralogy , geotechnical engineering , geology , materials science , composite material , oceanography , organic chemistry
Swelling characteristics of compacted bentonite when hydrated with a hypersaline pore fluid (332 g/L total dissolved solids; 6.6 mol/L ionic strength) are reported. The pore fluid mimics the multiple constituents and their concentrations found for the Cobourg limestone of the Michigan Basin and is dominated by sodium (25% mole fraction) with some potassium, calcium, and magnesium (10%, 5%, and 4% mole fractions). Measurements of swell pressure for two sodium bentonites when hydrated under conditions of zero volume increase are reported. Swell pressure reached a peak within 10–30 h from the onset of hydration, followed by a continual decrease over 1 year of testing from chemical interaction between the bentonite and pore fluid. After 1 year, the swell pressure of the MX-80 bentonite tested decreased by a factor of nine relative to the peak swell pressure with deionized water when the dry density was 1.6 Mg/m 3 . Swell pressures increased as dry density increased. However, chemical interactions appear to have more influence on swell pressure than density for the pore fluid examined as a swell pressure of just under 1200 kPa was measured for MX-80 after 1.8 years of hydration when compacted to the highest dry density of 1.8 Mg/m 3 examined.