Thesis (M.Sc.)--Université du Québec à Montréal, 2002. / Includes bibliographical references (leaves 111-114).

Hay and straw bales can be stacked up like giant insulating bricks to form load-bearing walls for a wide variety of structures. The technique could provide home builders with inexpensive, energy efficient, long-lasting, fire-resistant, easily built, comfortable houses from a natural resource yearly renewable and locally available. Unfortunately, the lack of knowledge regarding the structural properties of the bales and the wall systems incorporating them presents a major barrier to straw-bale construction. Without the quantitative information that standard engineering testing would provide, the wider use of bale construction will continue to be severely inhibited. This thesis examines the basic mechanical properties of individual straw bales (stress-strain behavior, ultimate strength, Poisson's ratio, etc ...), and prototype wall systems (vertical strength, in-plane lateral strength, out-of-plane lateral strength, deflection, creep, etc ...). The results of the tests on the individual bales as well as the wall systems are used to develop guidelines and equations for the design of straw-bale structures.

As the effects of global warming and the exhaustion of natural resources become more and more evident, the importance of low-impact construction alternatives is becoming increasingly apparent. Conventional construction not only irreversibly drains natural resources; it is also responsible for the great amount of energy consumed in the production of building materials. Natural renewable materials that offer low-impact, low-embodied energy construction alternatives have promising potential for the construction industry. This thesis provides an insight into construction with natural materials, with particular emphasis on straw bale construction, by undertaking an embodied energy analysis. Firstly, the existing published sources were studied to obtain the embodied energy values of various construction materials relevant to conventional residential and straw bale construction. The embodied energy values for straw bales were found to have great variation from source to source. To obtain the value appropriate for the Canadian situation, the analysis completed in this thesis utilizes published material on straw and biomass. Secondly, a comparative analysis of embodied energy for various wall systems was completed. This analysis proves that straw bale construction is an effective low impact alternative to conventional residential construction styles. In particular, the embodied energy of the straw bale wall section is six times smaller than that of the most common conventional construction style - wood-frame with brick siding. Finally, the component of the straw bale wall that has the highest embodied energy – plaster – was examined to investigate further reduction of the embodied energy of the straw bale wall. As a result of this investigation it was found that the plaster mix containing increased amounts of cementitious materials (for example, equal parts of cement and lime) has smaller embodied energy value. The findings of this work can be utilized both in the conventional construction industry as a guide to making environmentally mindful decisions, as well as for natural building construction to further improve the performance of straw bale structures. / Thesis (Master, Environmental Studies) -- Queen's University, 2010-01-28 16:18:47.585

The principal research for this study is into the invention and use of Solomit, a compressed straw building plate, which became available when a fibre bale building method also sought to ease the European post-Great War housing shortage. Both methods were patented in France in the early 1920s. Solomit patents registered by Serge Tchayeff in France, Australia, and Britain, and patents for bale building by Emile Feuillette registered in France and the US, are analysed. The vernacular precedents of both are argued. The South Australian patents connected to Solomit and registered during the later 1930s are discussed. This study broadly establishes the history of the initial South Australian venture (1935-1937) to manufacture Solomit under licence from Germany and to establish widespread Solomit construction; it notes Solomit's admission (in principle) to the Building Act 1940 (SA); and identifies examples of government building tenders won by the company. Although certain evidence establishes the naivety of the South Australian enterprise about German socio-political realities of 1933-1937, I consider the possibility that Australian Solomit manufacture may have held political promise for the NSDAP (German Nazi Party) in Australia, and follow an assumption that in South America, strongly influenced by NSDAP Germany, the aggressor exploited Solomit for import-export advantages tenuously connected to building projects. / The study suggests that a likely model for Australian Solomit demonstration building was the artisans' housing proposed in the early 1920s by the Swiss-French architect Le Corbusier (1887-1965); and it brings forward Tchayeff and Le Corbusier's collaboration in use of Solomit, particularly in building the Pavillon de L'Esprit Nouveau (1924-1925), thereby emphasising an aspect of this exhibition prototype house previously inadequately exposed. Solomit was manufactured at Berlin from 1929 and was used for urban dwelling extensions and improved thermal insulation. The much wider use of Solomit during the inter-war years, and particularly with the onset of the Great Depression, for German city-peripheral settlements, and in the Weimar Republic and later NSDAP governments' push for Eastlands settlement, is explored. It is probable that in Germany Solomit was overtaken by concurrent and energetically improved efficiencies in building materials and that by the late 1930s little purpose was seen for a material then viewed as regressive. The fate of the South Australian Solomit company showed certain parallels. The relationship of German austerity building of the 1920s to the existing vernacular building methods which were encouraged by government as economical substitutes is explored. These vernacular methods, encouraged by the Republic immediately before Solomit's first production in Germany, are related to Solomit's adoption. Surviving South Australian Solomit houses (built from 1938 to 1961) and other local Solomit constructions (some demolished) are identified. Contrary to some original Australian perceptions, existing Solomit buildings - the walls of which several owners describe as 'hollow' - have generally proved durable. This study maps the extent of South Australian Solomit building; and the penultimate chapter gives to it a pictorial overview. Non-constructional thermal and acoustic Solomit sheeting is currently manufactured in Victoria. Recent Canadian interest in Australian Solomit for its use in fibre bale building suggests a possibly wider future use of Solomit. This study rediscovers Solomit's invention and aspects of its European and Australian use and assessments, and provides a part of the history of a largely forgotten building material. / Thesis (PhDArchitectureandDesign)--University of South Australia, 1998.

The use of plastered straw bale walls in residential construction is growing as builders and owners seek environmentally friendly alternatives to typical timber construction practices. Straw has excellent insulation properties and is an agricultural bi-product which is annually renewable, and is often considered a waste product of grain production. This thesis presents new models for predicting the compressive strength of plastered straw bale assemblies subjected to concentric and eccentric load. A constitutive model for lime-cement plaster is adapted from a stress-strain model for concrete, available in the literature. Twenty-two cylinder tests on plasters typically used for straw bale construction were used to verify the constitutive model. The models for plastered straw bale assemblies were verified by testing plastered straw bale assemblies under concentric and eccentric compressive loads. An innovative steel frame test jig was designed to facilitate fabrication and testing of the specimens. Using this jig, 18 specimens of height 0.33 m, 0.99 m, 1.05 m or 2.31 m were subjected to concentric or eccentric compressive load until failure. The experimental strengths of the assemblies ranged from 23 kN/m to 61 kN/m, depending on the eccentricity of the load, the plaster strength, and the plaster thickness. Results indicated that the specimen height did not significantly influence the strengths of the specimens. The models predicted the ultimate strength of the assemblies to be, on average, 6% less than the experimentally determined strengths, with a standard deviation of 13%. The models were also used to predict the theoretical ultimate strengths for a number of plastered straw bale wall assemblies described in the literature. The fabrication techniques for these specimens were more representative of conventional straw bale construction techniques, and it was found that the experimental results were 30% of the theoretical strengths for assemblies with plaster strength less than 10 MPa and 6% of the theoretical strengths for assemblies with plaster strength greater than 10 MPa. Thus, to account for construction imperfections and potential alternative failure mechanisms, a reduction factor of no more than 0.3 for plaster less than 10 MPa is suggested in order to predict the strength of plastered straw bale walls constructed using conventional construction techniques. The results presented herein provide support for the use of plastered straw bale walls in residential construction and indicate the applicability of models based on the compressive behaviour of lime-cement plaster for modelling the behaviour of plastered straw bale walls under eccentric and concentric compression. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-05-29 13:34:53.867

There is a growing interest in straw bale construction for its low embodied energy and insulation value. Early studies of its structural behaviour and fire resistance have shown it to be a viable alternative to traditional building techniques. However, the biggest remaining obstacle to widespread acceptance is the moisture behaviour within the straw bale walls, especially as it concerns mould growth. The uncertainty of this behaviour leads to the hesitation of building officials and insurance providers to freely accept straw bale construction. Therefore, this study investigates the moisture, temperature and mould growth in straw bale walls, through a combination of analysis, dynamic modeling and field studies. A study of mould is presented along with the current methods available for predicting mould growth. Moisture is the primary controllable factor to mould growth in buildings. Therefore, an understanding of moisture accumulation within straw bale walls is necessary to provide a safe design that precludes mould growth. This study compiles the current state of knowledge of the hygrothermal properties of the materials used in straw bale walls. Then a parametric steady-state analysis is conducted to show the expected behaviour of vapour diffusion and the effects of the material properties. Two 14”thick x 6’ wide x 8’ high straw bale test walls were constructed: one was rendered with a typical cement-lime plaster and the other with a clay plaster. Temperature and moisture were monitored throughout the walls for over a year. These test walls provide more information on the macro behaviour of the walls to both vapour diffusion and, more importantly, rain. Hygrothermal computer modeling was conducted and compared to the test data to assess its accuracy. Thermal modeling was successful, while moisture modeling was found to be more difficult due to a lack of accurate rain data. With better climate data it is expected that accurate hygrothermal modeling of straw bale walls is possible. The result of this work is a general starting point for more detailed studies of the hygrothermal behaviour of straw bale walls with the ultimate goal of assessing the mould risk for various construction techniques and locations.

There is a growing interest in straw bale construction for its low embodied energy and insulation value. Early studies of its structural behaviour and fire resistance have shown it to be a viable alternative to traditional building techniques. However, the biggest remaining obstacle to widespread acceptance is the moisture behaviour within the straw bale walls, especially as it concerns mould growth. The uncertainty of this behaviour leads to the hesitation of building officials and insurance providers to freely accept straw bale construction. Therefore, this study investigates the moisture, temperature and mould growth in straw bale walls, through a combination of analysis, dynamic modeling and field studies. A study of mould is presented along with the current methods available for predicting mould growth. Moisture is the primary controllable factor to mould growth in buildings. Therefore, an understanding of moisture accumulation within straw bale walls is necessary to provide a safe design that precludes mould growth. This study compiles the current state of knowledge of the hygrothermal properties of the materials used in straw bale walls. Then a parametric steady-state analysis is conducted to show the expected behaviour of vapour diffusion and the effects of the material properties. Two 14”thick x 6’ wide x 8’ high straw bale test walls were constructed: one was rendered with a typical cement-lime plaster and the other with a clay plaster. Temperature and moisture were monitored throughout the walls for over a year. These test walls provide more information on the macro behaviour of the walls to both vapour diffusion and, more importantly, rain. Hygrothermal computer modeling was conducted and compared to the test data to assess its accuracy. Thermal modeling was successful, while moisture modeling was found to be more difficult due to a lack of accurate rain data. With better climate data it is expected that accurate hygrothermal modeling of straw bale walls is possible. The result of this work is a general starting point for more detailed studies of the hygrothermal behaviour of straw bale walls with the ultimate goal of assessing the mould risk for various construction techniques and locations.

The search for more sustainable construction methods has created a renewed interest in straw bales technology. Straw bales are a composite material that is energy efficient and durable. Rectangular straw bales stacked in a running bond and plastered on the interior and exterior faces have adequate strength to resist typical loads found in two-storey structures. The structural behaviour of a load-bearing plastered straw bale wall subject to uniform loading is well researched. However, door and window voids in the wall redistribute vertical load paths and produce areas of concentrated stress. This thesis describes experiments on small-scale plastered straw bale panels subjected to loading conditions that simulate the loading conditions experienced in areas around door and window voids. Twenty-one specimens were tested under two main types of loading conditions. The specimens were rendered with lime-cement plaster, were one to three bales (0.33 m to 0.99 m) in height, and were either unreinforced, or contained metal diamond lath or chicken wire embedded within the plaster. The specimens were pin-supported at various centre-to-centre distances ranging from 200 mm to 500 mm and were loaded either uniformly or by a point load. Two distinct types of failure were observed. Strut-and-tie models were developed to describe the structural behaviour of panels undergoing vertical cracking of the plaster skin at failure. Bearing models were developed to describe the structural behaviour of panels undergoing crushing of the plaster skin beneath the point of applied load. The models predicted the correct failure mode of 92% of the specimens and had an average ratio of experimental strength to theoretical strength of 0.95 with a standard deviation of 0.17. The results show that the behaviour of plastered straw bale walls can be predicted using common methods of structural analysis. A parametric analysis of door and window voids within plastered straw bale walls is presented. / Thesis (Master, Civil Engineering) -- Queen's University, 2010-09-30 11:32:53.613

The performance of plastered straw bale walls with respect to wind-driven rainfall was investigated in this thesis. The absorption coefficient, which describes the rate of water infiltration, was measured for 14 plaster types, twelve different earth plasters and cement and lime plasters. The absorption coefficient was measured during uptake of water from a free reservoir. The effective porosity of these plasters, which describes the moisture storage capacity and the degree of protection that a plaster offers to straw bales, was also determined by submersion in water. An analytical model employing the absorption coefficient, the effective porosity, and climatic data was used to predict and compare plaster performance and to demonstrate the usefulness of this type of data. Simulated wind-driven rainfall experiments were also conducted on two plaster types. The results indicate that the static test used to measure the absorption coefficient can reasonably be used to predict actual wind-driven rainfall infiltration.

The performance of plastered straw bale walls with respect to wind-driven rainfall was investigated in this thesis. The absorption coefficient, which describes the rate of water infiltration, was measured for 14 plaster types, twelve different earth plasters and cement and lime plasters. The absorption coefficient was measured during uptake of water from a free reservoir. The effective porosity of these plasters, which describes the moisture storage capacity and the degree of protection that a plaster offers to straw bales, was also determined by submersion in water. An analytical model employing the absorption coefficient, the effective porosity, and climatic data was used to predict and compare plaster performance and to demonstrate the usefulness of this type of data. Simulated wind-driven rainfall experiments were also conducted on two plaster types. The results indicate that the static test used to measure the absorption coefficient can reasonably be used to predict actual wind-driven rainfall infiltration.