The level of moisture a construction is exposed to may have an adverse effect on health and structure. Using straw, an organic material, as the construction medium, introduces concerns about biodegradability and spore germination, highlighting the uncertainties surround the level at which straw is susceptible to decay. A physical model is presented in this thesis offering a method by which to quantify and evaluate the risk posed to straw bale constructions from moisture. The model, utilising the development of an innovative Risk Assessment System based on fuzzy logic, is supported by empirical research conducted in static and dynamic environments. The model relies upon the interpretation of data provided by monitoring devices, and an understanding as to the complexities of vapour transition through a straw bale and the interaction of moisture within. Using commonly descriptive terminology to describe the risk posed to the straw, the model, is capable of providing a greater understanding of straw bale construction and advising interested parties on potential weaknesses, taking into account: moisture, temperature, historic and predicted environmental conditions, limitations of analytical techniques, and the effect of direct sunlight. The concept of the model is to provide an early response mechanism to warn of the potential of adverse effects and thereby averting the need for destructive investigation and remedial action. The interpretation of monitoring device data underpins the research conducted in this thesis, prior to which, there existed a gap in knowledge concerning the understanding of how moisture interacts with straw. The development of a novel compressed straw probe, as a monitoring device, offers the ability to establish an immediate moisture content measurement using a resistance meter, or of recent moisture levels using gravimetric analysis, supported by olfactory and visual verifications, enhancing the accuracy. Monitoring device results, compensated for temperature and density by equations developed from empirical data, are applied to a contour plot, via the Risk Assessment System, to provide an diagrammatic interpretation of the risk posed. Any potential problem is then flagged and a report generated providing advice. Other contributions to knowledge made within the thesis consist of: monitoring device evaluations, determining the rate at which moisture is transferred through a bale, defining the interaction of moisture with straw, the capacity for moisture storage of renders and the subsequent implications, identification of transient moisture and the effect of solar gain, resistance meter calibration, and the hygroscopic, hydrophobic and hydrophilic tendencies of straw.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:639932 |
| Date | January 2014 |
| Creators | Robinson, Julian A. |
| Publisher | Nottingham Trent University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://irep.ntu.ac.uk/id/eprint/188/ |
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