Detection of moisture differences of a swellable and a non-swellable clay in the low and mid frequency range
2011 (English)In: 6th Conference on Innovative Moisture Measurement in Research and Practise, Karlsruhe, Oct. 2011, 2011, 10pp- p.Conference paper (Refereed)
The sensitivity of dielectric spectroscopy to display changes in moisture content was studied for one swellable (bentonite) and one non-swellable clay (illite) in the low (1.0E-04…1.0E+06 Hz) and mid (2.0E+08…1.1E+09 Hz) frequency range. Therefore, both air dry materials were stored until equilibration at 11% and 93% relative humidity (r.h.) and their volumetric water content (Wvol) was measured with static and dynamic heating as well as with dielectric spectroscopy. Transformation of complex permittivity to Wvol was accomplished using the calibration functions after Topp and Roth. Moisture distinction could be displayed for both materials in the lower frequency range, whereas the changes in water content could only be described for the illite within the mid frequency range. Estimation of volumetric water content by transformation of real relative permittivity with Topp-function, resulted in underestimation of Wvol, especially for samples stored at high relative humidity (93% r.h.). Determination of Wvol with the calibration function after Roth was successful for illite at 11% r.h., but failed at higher relative humidity and for the bentonite in both hydration states. Additionally, complex dielectric data were clearly influenced by other processes beside bound water polarization.
Place, publisher, year, edition, pages
2011. 10pp- p.
Soil Science Engineering and Technology
Research subject Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-164055OAI: oai:DiVA.org:uu-164055DiVA: diva2:466081
6th Conference on Innovative Moisture Measurement in Research and Practise, Karlsruhe, 12-14 Oct 2011