Earth building materials or unfired clay masonry have a strong potential to regulate indoor humidity variations. This was identified through observations of historical buildings where earth was used as a major building material. A stable relative humidity provides many benefits such as a healthier environment for the occupants, a reduced surface condensation or a reduced energy consumption for air conditioning systems. Building physicists have started to bring attention to this phenomenon called moisture buffering where the building envelope plays a major role in the moisture balance of the building. Yet only a limited amount of research has been done on one of the most promising materials in terms of moisture buffering performance. This study aimed to characterise the moisture buffering capacity of unfired clay masonry. Steady-state and dynamic hygric properties of 146 samples were measured. A selection of soils were selected to represent the high variability of these building materials and to determine the influence of composition and material properties on moisture buffering. The moisture buffering test protocol used was primarily based on the Nordtest project yet the influence of boundary conditions and test protocol was investigated to obtain reliable dynamic results. This showed that results from different boundary conditions could be compared as they remained proportional. The surface film resistance showed to have a significant influence. Additional investigations were made on the dynamic adsorption process using a Dynamic vapour sorption (DVS) system which showed the influence of the hysteresis. Samples were prepared as compressed earth blocks (CEB) or plasters. The CEB and plasters were further investigated with the addition of natural fibres to explore the potential to improve their buffering capacity. Overall not only was the performance of the materials characterised but it could be identified which properties influence the adsorption capacity also it was possible to compare the results with existing classifications for buffering materials. It became clear that not only are these materials out performing most of conventional materials but their own performance can also be adjusted and improved for required applications.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:633171 |
| Date | January 2014 |
| Creators | Mcgregor, Fionn |
| Contributors | Heath, Andrew ; Shea, Andrew ; Fodde, Enrico |
| Publisher | University of Bath |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0026 seconds