Adding waste paper to clay plaster to raise its ability to buffer moisture

• Main Authors: Ardo Kubjas, Lembit Nei, Nele Nutt
• Format: Article
• Language: English
• Published: Estonian Academy Publishers 2020-05-01
• Series: Proceedings of the Estonian Academy of Sciences
• Subjects: materials science; composite material; moisture buffer value; nordtest; plaster; clay; wastepaper.
• Online Access: https://kirj.ee/public/proceedings_pdf/2020/issue_3/proc-2020-3-179-185.pdf

The Nordtest method evaluates the moisture buffer value (MBV) of materials that are being exposed to indoor air. The test simulates daily variations (high RH of 75% for 8 hours, low RH of 33% for 16 hours) in MBV, which in this context refers to the moisture uptake/release in the material when it is exposed to relative humidity (RH) in a square wave. We are looking for ways to increase clay plasterâs ability to buffer moisture. Which material has simultaneously a higher ability to buffer moisture and can be added to the clay plaster mixture? The recipe for the specimen included the following: waste paper (newspaper paper), glue (methylcellulose), clay and water. Our research showed that adding paper plaster mixture to the clay plaster mixture increases the moisture buffering ability of the plaster. The bigger the amount of added paper plaster, the better the plasterâs ability to buffer moisture.