Determination of the moisture diffusivity of rammed earth from transient capillary absorption moisture content profiles

• Published in: Construction & building materials Vol. 318; p. 125978
• Main Authors: Indekeu, Margaux L., Janssen, Hans, Woloszyn, Monika
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 07-02-2022; Elsevier
• Subjects: Boltzmann transformation; Capillary absorption; Characteristic profile; Civil Engineering; Construction durable; Engineering Sciences; Equivalent length; Moisture diffusivity; Moisture profile; Multilayer composite; Rammed earth; X-ray radiography; Boltzmann transformation; Capillary absorption; Characteristic profile; Multilayer composite; Equivalent length; Moisture profile; X-ray radiography; Rammed earth; Moisture diffusivity
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.125978

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•The moisture diffusivity of rammed earth is studied by modifying the X-ray method.•A confinement eliminates disturbances by material evolution during the test.•The Boltzmann transformation is corrected for the presence of a wick and paper.•This is done via their hydraulically equivalent height in the capillary absorption.•Taking this equivalent height into account is indispensable for the studied cases.
The determination of the moisture diffusivity in the capillary range is studied for rammed earth building materials, using the X-ray method. To prevent liquefaction and expansion of these materials during the capillary absorption test, a brick wick and paper are added as lower sample parts and a confining sealing is utilised. Since the wick and paper bring about a composite case, the compatibility with the Boltzmann transformation must be redeveloped. It is found that the solution lies in adjusting the Boltzmann transformation through the equivalent height capturing the hydraulic impact of the wick and paper on the capillary absorption process.