Abstract
The pressure plate is one of the most widely used methods to measure the moisture retention curves of porous materials in the over-hygroscopic range. Due to its working principle and operational protocol, the traditional pressure plate method is only applicable to the desorption process. In this study, we propose a novel method to measure the moisture retention curves for the adsorption process. Only simple modifications to the traditional pressure plate setup are needed, and minor changes in the experimental procedures are required. Validation measurements are performed on three representative porous building materials: calcium silicate, autoclaved aerated concrete and ceramic brick. Results from the modified pressure plate method are compared with those from the semi-permeable membrane and the psychrometer methods. The modified pressure plate method successfully provides similar results to the other two established methods for all three materials, and hence proves to be reliable in determining the adsorption moisture retention curves in the over-hygroscopic range.
Highlights
Moisture has a significant impact on buildings and the built environment: buildings’ energy efficiency and components’ service life and the indoor climate and air quality are closely related to moisture [1,2,3,4]
In the over-hygroscopic range where liquid water plays a more important role, such functions are called moisture retention curves, in most cases measured through the pressure plate method [7]
We propose a differently modified pressure plate for the adsorption process (Fig.2)
Summary
Moisture has a significant impact on buildings and the built environment: buildings’ energy efficiency and components’ service life and the indoor climate and air quality are closely related to moisture [1,2,3,4]. It is of great value to have a profound understanding and optimized control of moisture-related processes within building envelopes. To analyze these processes, the hygric properties of porous building materials are usually indispensable. In the over-hygroscopic range where liquid water plays a more important role, such functions are called moisture retention curves, in most cases measured through the pressure plate method [7]. Fredriksson and Johansson [11] modified the traditional pressure plate and applied it to the adsorption process of brick and spruce. 32.6 11.6 a Determined from dry cup test (RH 11.3% ~53.5%); b Adsorption from the dry state; c Values for 20°C; d Cannot be determined accurately
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
