Porosity evolution of free and confined bentonites during interlayer hydration
Likos, William J. (University of Missouri-Columbia. Department of Civil and Environmental Engineering)
Wayllace, Alexandra (Colorado School of Mines. Engineering Division)
Fecha: |
2010 |
Resumen: |
Methods for predicting the volume change and swelling-pressure behavior of expansive clays require detailed understanding of coupled interactions between clay microstructure and macrostructure under hydraulic, thermal, and mechanical loads. In this study a suite of water-vapor sorption experiments was conducted using compacted bentonites hydrated in controlled relative humidity (RH) environments maintained under free and constrained volume-change boundary conditions. Emphasis was placed on examining the influences of compaction and predominant exchange cation on the water uptake, volume change, and swelling pressure response. Densely compacted specimens exhibited greater volume changes under free swelling conditions and greater swelling pressures under fully confined conditions. Water uptake, volume change, and swelling pressure were all more significant for Colorado (Ca2+/Mg2+) bentonite than forWyoming (Na+) bentonite. Plastic yielding, evident as a peak in the relationship between swelling pressure and RH, was more evident and occurred at lower RH for the Colorado bentonite. This observation was interpreted to reflect the limited capacity for interlayer swelling in Ca/Mg bentonites and corresponding structural collapse induced by the onset of water uptake in larger intra-aggregate and inter-aggregate pores. A semi-quantitative model for the evolution of clay microstructure resulting from interlayer hydration was considered to attribute the experimental observations to differences in the efficiency with which transitions in basal spacing translate to bulk volume changes and swelling pressure. Results provide additional insight and experimental evidence to more effectively model the mechanical behavior of compacted bentonites used as buffer or barrier materials in waste repository applications. |
Derechos: |
Tots els drets reservats. |
Lengua: |
Anglès |
Documento: |
Article ; recerca ; Versió publicada |
Materia: |
Bentonite ;
Dehydration ;
Hydration ;
Interlayer Swelling ;
Smectite ;
Sorption |
Publicado en: |
Clays and Clay Minerals, Vol. 58, Núm. 3 (2010) , p. 399-414, ISSN 1552-8367 |
DOI: 10.1346/CCMN.2010.0580310
16 p, 1.2 MB
Acceso restringido a la UAB
|
El registro aparece en las colecciones:
Artículos >
Artículos de investigaciónArtículos >
Artículos publicados
Registro creado el 2020-06-10, última modificación el 2023-06-03