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Energy and Buildings 43 (2011) 1960–1967

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Energy and Buildings
journal homepage: www.elsevier.com/locate/enbuild

Performance of straw bale wall: A case of study
Taha Ashour a,∗ , Heiko Georg b , Wei Wu c
a b c

Agricultural Engineering Department, Faculty of Agriculture, Benha University, Egypt Institute of Organic Farming, von ThünenInstitute (vTI), Westerau, Germany Institute of Geotechnical Engineering, University of Natural Resources and Applied Sciences, 1180 Vienna, Austria

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This research aimed to evaluate a straw bale house located in Bavaria, Germany. An extensive test program was carried out. The experimental work includes compression tests, moisture content, thermal stabilityof bales and pH. The in situ work includes temperature and relative humidity inside the straw bale wall. The stress–strain behavior of straw bales was investigated including nonlinearity and anisotropy. Thermal stability of bales under constant temperature and relative humidity was studied considering time dependence. The moisture content of straw bale was about 11%, while pH value inside the balewas about 7.29. Moreover, the temperature and the relative humidity between the interior (inside straw bale wall) and the exterior were investigated. © 2011 Elsevier B.V. All rights reserved.

Article history: Received 13 December 2010 Received in revised form 3 February 2011 Accepted 3 April 2011 Keywords: Straw bale house Moisture content pH Thermal stability of bales Temperature Relativehumidity

1. Introduction Straw is a natural product, grown by photosynthesis during a half or one-year period, fueled by the sun. Straw is currently produced in surplus to requirements, so it is cheap and easily accessible in most countries. It is the end product of growing crops; so using it for building purposes present a sustainable and ecological way of recycling. The use of straw bales asconstruction material has many advantages [1]. Buildings with straw bales are energyefficient, durable, attractive and even fire-resistant. According to Desborough and Samant [2], the public would generally accept straw dwellings, especially when supported by wide dissemination of information about the material properties of straw and the construction possibilities. Additionally, built environmentprofessionals find straw to be an excellent construction material and recognize that some of its limitations can easily be overcome. Earlier studies [3] showed that a compacted straw bale with a render layer of about 4 cm on all sides survived an externally imposed heat flux of 29 kW m−2 for 10 min without severe cracking of the render or ignition of the straw within the bale. A straw bale without renderreadily ignited when subjected to the same heat flux. Clearly, the render contributes to the fire safety of straw bale construction by providing an insulating barrier between the heat source and the straw and also providing a barrier to oxygen transfer from

∗ Corresponding author. E-mail addresses: thashour@hotmail.com, taha.ashour@boku.ac.at (T. Ashour). 0378-7788/$ – see front matter © 2011Elsevier B.V. All rights reserved. doi:10.1016/j.enbuild.2011.04.001

the atmosphere into the straw. Straw bales have also been used to provide retrofit insulation for existing homes. The bales are much cheaper that adobe and have become common in high-end estate constructions. On the other hand, faced with the worldwide shortage of forest resources, the construction industry is showing interest inthe production of particleboard from agricultural residues [4]. Agoudjil et al., [5] reported that date palm wood is a good candidate for the development of efficient and safe insulating materials when compared to the other natural materials. While Becchio et al. [6] studied the effects of the addition of wood aggregates on both mechanical and thermal properties of concrete. Goodhew and Griffiths...