This paper discusses earth as a building material and the extent to which earth building technology has evolved over the years. In particular it addresses the adobe, compressed and rammed earth techniques of earth building as suitable techniques for Liberia consumption. In addition, the paper investigates the suitability of the Latosols soils of Liberia for earth building construction purposes using standardized earth building principles and requirements. A local Johnson City, Tennessee, earth sample found to have the same physical characteristics of the Latosols of Liberia was used to simulate Liberia soils to produce specimen blocks at different configurations of moisture content and stabilizers (Bentonite and cement). Following 14 days of cure, the blocks were tested for compressive strength. It was found that blocks produced from the natural soil with no stabilizer added were structurally adequate for building construction purposes. A cost-benefit analysis involving blocks with and without stabilizer (cement) added was also performed.

Mu Jun. / Thesis submitted in: December 2005. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 181-183). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Issues and Background --- p.5 / Chapter 2.1. --- Why Ecological Architecture? --- p.5 / Chapter 2.1.1. --- Fossil Fuels and Environmental Issues --- p.5 / Chapter 2.1.2. --- The Buildings' Role in the Issues --- p.9 / Chapter 2.2. --- Knowledge in Ecological Design --- p.11 / Chapter 2.2.1. --- About Ecological Architecture --- p.11 / Chapter 2.2.2. --- Thermal Study ~ A Significant Way to Ecological Architecture --- p.13 / Chapter 2.2.3. --- What is Suitable Ecological Architecture for Loess Plateau areas of China --- p.16 / Chapter 3. --- Defining the Future Ecological Architecture in Loess Plateau Areas --- p.20 / Chapter 3.1. --- Economy for Building --- p.20 / Chapter 3.1.1. --- Situation --- p.20 / Chapter 3.1.2. --- Technological Strategies towards a Cost-effective Ecological Approach --- p.22 / Chapter 3.1.3. --- Alternative-Technological Approach --- p.24 / Chapter 3.2. --- Climate --- p.25 / Chapter 3.2.1. --- Climatic Characteristics --- p.25 / Chapter 3.2.2. --- A climatically Responsive Approach ~ Selective Environmental Design --- p.32 / Chapter 3.2.3. --- Climatic Response of Thermal Design Guidelines --- p.33 / Chapter 3.2.3.1. --- Minimizing Heat loss through Building Fabrics --- p.34 / Chapter 3.2.3.2. --- Utilization of Available Natural Energy --- p.37 / Chapter 3.3. --- Benefits from Vernacular Architecture --- p.45 / Chapter 3.3.1. --- Earth ArchitecturéؤVernacular Architecture on Loess Plateau --- p.45 / Chapter 3.3.1.1. --- Classification --- p.46 / Chapter 3.3.1.2. --- Environmental Performance --- p.53 / Chapter 3.3.2. --- Literature Review of Studies on Earth Architecture --- p.58 / Chapter 3.3.2.1. --- Properties of Earth-based Materials --- p.58 / Chapter 3.3.2.2. --- Literature on Earth Architecture --- p.60 / Chapter 3.3.3. --- Issues and Development --- p.76 / Chapter 3.3.3.1. --- Limitation in Existing Earth Architecture of Loess Plateau --- p.76 / Chapter 3.3.3.2. --- Recent Research on Developing Earth Architecture in Loess Plateau Areas --- p.77 / Chapter 3.3.3.3. --- Considerations --- p.81 / Chapter 3.4. --- Conclusion --- p.82 / Chapter 4. --- Making of the Classroom as Designed for the Thermal Study --- p.84 / Chapter 4.1. --- Why a Classroom? --- p.84 / Chapter 4.2. --- The School Project and the Classroom Simulated --- p.85 / Chapter 5. --- Thermal Study by Simulating Experiments --- p.88 / Chapter 5.1. --- Research Methodology --- p.88 / Chapter 5.2. --- Program Validation --- p.89 / Chapter 5.3. --- Experimental Series of Simulation and Model Setup --- p.93 / Chapter 5.4. --- Thermal Mass and Insulation --- p.95 / Chapter 5.4.1. --- External Wall --- p.95 / Chapter 5.4.2. --- Roof Study --- p.97 / Chapter 5.4.3. --- "Windows, Doors and Glazing" --- p.100 / Chapter 5.4.4. --- Incorporated Performance --- p.103 / Chapter 5.5. --- Passive system for natural energy use --- p.106 / Chapter 5.5.1. --- Passive Solar System Study --- p.106 / Chapter 5.5.1.1. --- Wall-based Passive Solar System --- p.106 / Chapter 5.5.1.2. --- Roof-based Passive Solar System --- p.125 / Chapter 5.5.1.3. --- System Comparison in Thermal Performance --- p.135 / Chapter 5.5.2. --- Natural Ventilation System with the Heat Exchanger --- p.137 / Chapter 5.5.2.1. --- Pre-warming Effect of the Solar Space --- p.139 / Chapter 5.5.2.2. --- Effect of the Earth-air-tunnel --- p.142 / Chapter 5.5.2.3. --- Incorporation with the Chimney --- p.153 / Chapter 5.5.2.4. --- Comparison in Performance --- p.158 / Chapter 5.6. --- Summary --- p.159 / Chapter 6. --- Design Improvement and Performance Prediction --- p.162 / Chapter 6.1. --- System Incorporation and Design Improvement --- p.161 / Chapter 6.2. --- Thermal Performance Prediction --- p.167 / Chapter 7. --- Conclusion --- p.174 / Appendix --- p.179

Proposta: o setor da construção civil é responsável por grande parte do consumo de energia e recursos e da geração de resíduos, provocando impactos significativos sobre o meio ambiente. Algumas alternativas para se construir, reduzindo os impactos, envolvem o uso de materiais renováveis, como a palha, e de materiais minimamente processados, como a terra. Contudo, estes materiais pouco são referidos nos sistemas de classificação de edifícios ambientalmente amigáveis. Muitos edifícios, rotulados como sustentáveis, apenas refletem esforços para reduzir a energia incorporada e são, em muitos outros aspectos, convencionais. Objetivo: considerando a lacuna identificada, o objetivo deste trabalho é realizar uma avaliação de sustentabilidade de uma habitação de interesse social, construída no meio rural, com fardos de palha, terra e cobertura verde. Metodologia de pesquisa: a estratégia geral de pesquisa utilizada foi o levantamento de um caso. A definição dos critérios de avaliação foi embasada naqueles tradicionalmente incluídos em métodos existentes, porém as formas de caracterização foram adaptadas a dados e procedimentos acessíveis ao contexto nacional. Além de critérios ambientais, foram incluídos outros, econômicos e sociais, devido à importância de uma abordagem pluridimensional. A apresentação dos resultados dos critérios ambientais em três escalas (da edificação, dos subsistemas e dos materiais) permite identificar os subsistemas e materiais com maior potencial de impactos, explicitando os pontos fracos da habitação, além de facilitar a comparação, total ou parcial, com os resultados obtidos em pesquisas semelhantes. Resultados: verificou-se a incorporação de grande quantidade de materiais que produzem emissões tóxicas, além de apresentarem um alto consumo energético para transporte. Em contrapartida, devido à utilização, predominante, de recursos pouco processados, identificou-se um baixo dispêndio de energia para manufatura de materiais e um potencial de reaproveitamento satisfatório. Os custos iniciais da edificação são baixos, em relação a habitações de interesse social construídas com materiais convencionais, e medianos, em relação àquelas que empregam materiais não convencionais. Em termos sociais, verificou-se que as soluções adotadas são adequadas para a autoconstrução e para o resgate da capacidade de trabalho em mutirão, e que o projeto não atende requisitos mínimos de acessibilidade. / Proposal: the construction industry is responsible for a large consumption of energy and resources, and produces a large amount of wastes, determining considerable environmental impacts. Some alternatives to build in a way to reduce environmental impacts include the use of renewable materials and the use of materials which require minimum amount of processing, such as straw and earth. Nevertheless, these materials are hardly ever referred to in green building classification systems. Many buildings classified as environmentally friendly or green may simply reflect efforts to reduce the embodied energy and are, in most other aspects, conventional. Objective: considering the identified gap, this work’s aim is to evaluate a low-income rural house, built with straw bales, earth and a green roof. Methods: the assessment criteria definition was based on those traditionally included in existent methods, but adapted in accordance to national acessible data and proceedings. Besides environmental criteria, others like social and economics, were included. The results presentation in three analysis scales (of the construction, as a whole, of the subsystems and of the materials) allows the identification of the potencially most impacting materials and subsystems, expliciting the dwelling weak points, and facilitates total or partial comparision with other similar researchs results. Findings: a large number of materials that emit toxic gases, besides having a high energy consumption for materials transport, was identified. However, due to the predominant use of materials with a minimum processing, a low energy consumption for materials production and a sactisfatory reuse potential was identified. The dwelling’s initial costs are low, if compared to low-income houses built with conventional materials, becoming average, in regard to those built with non-convetional materials. In social terms, it was verified that the construction solutions are suitable to self-building and to rescue the ability of working cooperatively, and that the dwelling’s design does not supply the minimum requirement for spatial acessibility.

Proposta: o setor da construção civil é responsável por grande parte do consumo de energia e recursos e da geração de resíduos, provocando impactos significativos sobre o meio ambiente. Algumas alternativas para se construir, reduzindo os impactos, envolvem o uso de materiais renováveis, como a palha, e de materiais minimamente processados, como a terra. Contudo, estes materiais pouco são referidos nos sistemas de classificação de edifícios ambientalmente amigáveis. Muitos edifícios, rotulados como sustentáveis, apenas refletem esforços para reduzir a energia incorporada e são, em muitos outros aspectos, convencionais. Objetivo: considerando a lacuna identificada, o objetivo deste trabalho é realizar uma avaliação de sustentabilidade de uma habitação de interesse social, construída no meio rural, com fardos de palha, terra e cobertura verde. Metodologia de pesquisa: a estratégia geral de pesquisa utilizada foi o levantamento de um caso. A definição dos critérios de avaliação foi embasada naqueles tradicionalmente incluídos em métodos existentes, porém as formas de caracterização foram adaptadas a dados e procedimentos acessíveis ao contexto nacional. Além de critérios ambientais, foram incluídos outros, econômicos e sociais, devido à importância de uma abordagem pluridimensional. A apresentação dos resultados dos critérios ambientais em três escalas (da edificação, dos subsistemas e dos materiais) permite identificar os subsistemas e materiais com maior potencial de impactos, explicitando os pontos fracos da habitação, além de facilitar a comparação, total ou parcial, com os resultados obtidos em pesquisas semelhantes. Resultados: verificou-se a incorporação de grande quantidade de materiais que produzem emissões tóxicas, além de apresentarem um alto consumo energético para transporte. Em contrapartida, devido à utilização, predominante, de recursos pouco processados, identificou-se um baixo dispêndio de energia para manufatura de materiais e um potencial de reaproveitamento satisfatório. Os custos iniciais da edificação são baixos, em relação a habitações de interesse social construídas com materiais convencionais, e medianos, em relação àquelas que empregam materiais não convencionais. Em termos sociais, verificou-se que as soluções adotadas são adequadas para a autoconstrução e para o resgate da capacidade de trabalho em mutirão, e que o projeto não atende requisitos mínimos de acessibilidade. / Proposal: the construction industry is responsible for a large consumption of energy and resources, and produces a large amount of wastes, determining considerable environmental impacts. Some alternatives to build in a way to reduce environmental impacts include the use of renewable materials and the use of materials which require minimum amount of processing, such as straw and earth. Nevertheless, these materials are hardly ever referred to in green building classification systems. Many buildings classified as environmentally friendly or green may simply reflect efforts to reduce the embodied energy and are, in most other aspects, conventional. Objective: considering the identified gap, this work’s aim is to evaluate a low-income rural house, built with straw bales, earth and a green roof. Methods: the assessment criteria definition was based on those traditionally included in existent methods, but adapted in accordance to national acessible data and proceedings. Besides environmental criteria, others like social and economics, were included. The results presentation in three analysis scales (of the construction, as a whole, of the subsystems and of the materials) allows the identification of the potencially most impacting materials and subsystems, expliciting the dwelling weak points, and facilitates total or partial comparision with other similar researchs results. Findings: a large number of materials that emit toxic gases, besides having a high energy consumption for materials transport, was identified. However, due to the predominant use of materials with a minimum processing, a low energy consumption for materials production and a sactisfatory reuse potential was identified. The dwelling’s initial costs are low, if compared to low-income houses built with conventional materials, becoming average, in regard to those built with non-convetional materials. In social terms, it was verified that the construction solutions are suitable to self-building and to rescue the ability of working cooperatively, and that the dwelling’s design does not supply the minimum requirement for spatial acessibility.

Proposta: o setor da construção civil é responsável por grande parte do consumo de energia e recursos e da geração de resíduos, provocando impactos significativos sobre o meio ambiente. Algumas alternativas para se construir, reduzindo os impactos, envolvem o uso de materiais renováveis, como a palha, e de materiais minimamente processados, como a terra. Contudo, estes materiais pouco são referidos nos sistemas de classificação de edifícios ambientalmente amigáveis. Muitos edifícios, rotulados como sustentáveis, apenas refletem esforços para reduzir a energia incorporada e são, em muitos outros aspectos, convencionais. Objetivo: considerando a lacuna identificada, o objetivo deste trabalho é realizar uma avaliação de sustentabilidade de uma habitação de interesse social, construída no meio rural, com fardos de palha, terra e cobertura verde. Metodologia de pesquisa: a estratégia geral de pesquisa utilizada foi o levantamento de um caso. A definição dos critérios de avaliação foi embasada naqueles tradicionalmente incluídos em métodos existentes, porém as formas de caracterização foram adaptadas a dados e procedimentos acessíveis ao contexto nacional. Além de critérios ambientais, foram incluídos outros, econômicos e sociais, devido à importância de uma abordagem pluridimensional. A apresentação dos resultados dos critérios ambientais em três escalas (da edificação, dos subsistemas e dos materiais) permite identificar os subsistemas e materiais com maior potencial de impactos, explicitando os pontos fracos da habitação, além de facilitar a comparação, total ou parcial, com os resultados obtidos em pesquisas semelhantes. Resultados: verificou-se a incorporação de grande quantidade de materiais que produzem emissões tóxicas, além de apresentarem um alto consumo energético para transporte. Em contrapartida, devido à utilização, predominante, de recursos pouco processados, identificou-se um baixo dispêndio de energia para manufatura de materiais e um potencial de reaproveitamento satisfatório. Os custos iniciais da edificação são baixos, em relação a habitações de interesse social construídas com materiais convencionais, e medianos, em relação àquelas que empregam materiais não convencionais. Em termos sociais, verificou-se que as soluções adotadas são adequadas para a autoconstrução e para o resgate da capacidade de trabalho em mutirão, e que o projeto não atende requisitos mínimos de acessibilidade. / Proposal: the construction industry is responsible for a large consumption of energy and resources, and produces a large amount of wastes, determining considerable environmental impacts. Some alternatives to build in a way to reduce environmental impacts include the use of renewable materials and the use of materials which require minimum amount of processing, such as straw and earth. Nevertheless, these materials are hardly ever referred to in green building classification systems. Many buildings classified as environmentally friendly or green may simply reflect efforts to reduce the embodied energy and are, in most other aspects, conventional. Objective: considering the identified gap, this work’s aim is to evaluate a low-income rural house, built with straw bales, earth and a green roof. Methods: the assessment criteria definition was based on those traditionally included in existent methods, but adapted in accordance to national acessible data and proceedings. Besides environmental criteria, others like social and economics, were included. The results presentation in three analysis scales (of the construction, as a whole, of the subsystems and of the materials) allows the identification of the potencially most impacting materials and subsystems, expliciting the dwelling weak points, and facilitates total or partial comparision with other similar researchs results. Findings: a large number of materials that emit toxic gases, besides having a high energy consumption for materials transport, was identified. However, due to the predominant use of materials with a minimum processing, a low energy consumption for materials production and a sactisfatory reuse potential was identified. The dwelling’s initial costs are low, if compared to low-income houses built with conventional materials, becoming average, in regard to those built with non-convetional materials. In social terms, it was verified that the construction solutions are suitable to self-building and to rescue the ability of working cooperatively, and that the dwelling’s design does not supply the minimum requirement for spatial acessibility.

Building rammed earth structures provides a sustainable alternative to concrete. As a building material, rammed earth exhibits very varied physical and material properties depending on the proportion of constituting soil types. When very sandy soil is used in rammed earth production, the properties are different from when a clayey soil is used. This variability can be seen as a very great advantage in the use of rammed earth as a building material. Builders are able to adjust specific properties by changing mix proportions to obtain a desirable balance in the characteristics of the resulting rammed earth structure. This research work looks at selected mechanical and physical properties of different mixes of rammed earth. It describes typical range of values in density, thermal conductivity, ultrasonic pulse velocity, water ingress and compressive strength. It examines how these factors interrelate in the same soil mixes. Samples were prepared by blending various soil types in specific proportions to ensure that each definition of soil grade is as specific as possible. Unstabilised rammed earth was tested as was cement stabilised rammed earth. Rammed earth was tested at various levels of stabilisation and it was discovered that higher rates of stabilisation was not always beneficial to every material property. The research also looked into the potential disposal of waste materials in rammed earth. As rammed earth is a monolithic material that largely remains undisturbed throughout its life span, it was suggested that waste materials could be stored in an inert form inside of rammed earth rather than dumping it in otherwise agricultural landmass. Pulverised Fuel Ash and Palm Kernel Shells were identified as wastes to be disposed in rammed earth. Pulverised Fuel Ash, a by-product of industrial furnace is found in abundance in developed countries that burn carbonaceous materials in power plants. Disposals have been seen as a problem as only a small proportion of high loss on ignition (LOI) Pulverised Fuel Ash has found application. Palm Kernel Shell is a by-product of the oil palm industry and is currently a menace in many developing countries that need to dispose large quantities of the shell in landfills. At an early stage of the research, experimental trial runs quickly showed that these supposedly waste materials had a positive effect on some of the material properties of the rammed earth walls they were made into. This research effort evolved to look into exploiting these materials to improve the physical and material property of rammed earth and to suggest their effect on stabilised and unstabilised rammed earth. The extent to which these materials could be useful and the level at which diminishing returns set in was also investigated. It was discovered that soil mixes that would otherwise not be considered suitable for use in rammed earth wall production can now be utilised as their characteristics can be improved on simply by adding Pulverised Fuel Ash or Palm Kernel shell in the right proportion. Incorporating Pulverised Fuel Ash in rammed earth resulted in increased compressive strength. Palm Kernel shell improved thermal properties without compromising compressive strength.

Este trabalho busca otimizar a utilização de biomassa de macrófitas aquáticas na produção de adobe (tijolos de terra crua, secos ao sol), baseado na determinação e estudo de suas características físicas e mecânicas, assim como nas características físicas e químicas destas plantas. A pesquisa foi desenvolvida no reservatório de Salto Grande, no município de Americana - SP. Este lago está localizado em uma área com déficit de habitações de interesse social, apresentando altos índices de urbanização e industrialização, o que acarreta no seu avançado processo de eutrofização artificial, decorrente das ações antrópicas. As macrófitas aquáticas predominantes no reservatório (Brachiaria arrecta, Eichhornia crassipes e Pistia stratiotes) apresentam níveis elevados de metais pesados e nutrientes (nitrogênio e fósforo), o que torna inviável sua utilização como forragem ou fertilizante. A utilização desta biomassa em materiais de construção é aqui apresentada como uma alternativa de manejo integrado do lago, na forma de encapsulamento (ou solidificação / estabilização) destas substâncias químicas, além de possibilitar a autoconstrução de habitações de baixo custo. Uma outra função do uso da biomassa no adobe é a estabilização do solo, que apresenta alto teor de argila (59 %, com 21 % de silte e 20 % de areia, classificado como A-7-6 HRB) e sofreria grandes retrações durante o processo de secagem, com surgimento de fissuras excessivas e conseqüente redução de resistência mecânica dos tijolos. A adição da biomassa contribuiu com a redução destas fissuras e da massa específica dos tijolos. Os resultados demonstraram ser esta utilização perfeitamente viável, com expressiva retirada de biomassa (juntamente com os metais e nutrientes) do sistema, além de significativas melhorias na qualidade do adobe, tanto físicas como mecânicas. Em linhas gerais, Eichhornia crassipes se mostrou a mais eficiente neste aspecto. Além de tudo, os resultados da pesquisa mostram que, apesar do adobe ser talvez o mais antigo material de construção manufaturado, sua aplicação se mostra perfeitamente viável, numa perspectiva mais ampla de sustentabilidade, se apresentando como um material completamente ecológico e adequado para regiões tropicais. / This work intends to optimise the utilization of aquatic macrophyte biomass in the adobe (a sun-dried mud brick) production, based on the study of the physical and mechanical characteristics of these bricks and the macrophytes biomass estimate as well as their chemical characteristics. The research was developed in the Salto Grande Reservoir region, in Americana (a town in São Paulo State, Brazil). This lake is located in an area of high urbanization and industrialization level, with common dwelling deficit, which is in advanced artificial eutrophication process by human activity action. The aquatic macrophytes found in that place (Brachiaria arrecta, Eichhornia crassipes and Pistia stratiotes) present a high level of heavy metals and nutrients that make impracticable their utilization as forage or fertilizer. The biomass utilization in the construction of materials appears here as an alternative of integrated management of the lake in the stabilization/solidification (or “encapsulation") of these chemical substances, in addition to the fact that it makes possible the self-building of low cost dwellings. The other biomass function is to stabilize the soil that has a high clay concentration (59%, with 21% silt and 20% sandy) and would suffer a large drawing back during the drying process, with the introduction of excessive fissures. This biomass addition was made to reduce these fissures and the specific mass of the bricks. Besides, the research results show that, even though the adobe bricks are perhaps the oldest manufactured building material, their application persists practicable mainly in the sustainability hopes for being a completely ecological building material and adequate for the tropical regions.

No meio da Arquitetura e Construção com Terra, aspectos positivos relacionados à diminuição da degradação ao meio ambiente e à promoção de resultados benéficos ao desempenho das edificações são bastante difundidos entre seus simpatizantes e especialistas. No entanto, um tema que parece ser pouco explorado é o canteiro de produção desta arquitetura e as condições de atuação dos trabalhadores. O trabalho frequentemente é pesado, a quantidade de esforço físico necessária para a execução das diversas tarefas é alta, podendo ser excessiva e até degradante se as condições de operação no canteiro não estiverem devidamente equacionadas. Dada a altíssima frequência das situações de intensa exploração no setor da construção civil no Brasil e considerando o caráter fortemente artesanal da construção com terra, faz-se necessário conhecer como ocorre a produção desta arquitetura e se a mecanização parcial destes canteiros repercute em melhores condições de trabalho aos operários envolvidos. A partir de informações coletadas em entrevistas com trabalhadores, engenheiros e arquitetos envolvidos nos canteiros de produção da arquitetura e construção com terra, visitas a canteiros de produção desta arquitetura, além de informação complementar apresentada sobre estes canteiros na bibliografia especializada, é construída uma avaliação estruturada por uma análise qualitativa e crítica fundamentada na teoria crítica da arquitetura. A evolução do canteiro de obras passa pelo remanejamento e pela eliminação de algumas tarefas. A mecanização parcial permite que operários possam se deslocar, ou ser deslocados, a ocupações menos degradantes. No entanto, a inclusão de máquinas não ocorre primordialmente por este motivo, ela passa a ser considerada pois, ao confrontar o custo da mão de obra com o investimento em maquinário, este último começa a se revelar como financeiramente viável no Brasil. Portanto, a mecanização parcial que ocorre até agora não pretende ir além de um aumento na produtividade. Mesmo com a incorporação de algumas máquinas, parte dos trabalhadores seguem realizando outras tarefas bastante pesadas, muitas delas exaustivamente repetitivas. / Among Earthen Architectures supporters and experts, positive aspects related to low environmental degradation and to the promotion of better results to the building performance are well known. However, a subject that seems to be little explored is the construction site of this architecture and the conditions of operation of workers. The labor is often heavy and a high amount of physical exertion is required. If operating conditions at the construction site are not adequately addressed, the demands may be excessive and even degrading. Given the high frequency of intense exploration in the construction sector in Brazil, also considering the strong artisanal character of earthen construction, it is necessary to know how production takes place in this architecture and if the partial mechanization of these sites improves working conditions. Based on information collected in interviews with workers, engineers and architects involved in earth construction production sites, visits to these architecture building sites, in addition to supplementary information provided by the relevant literature, this paper will present an evaluation structured by a critical and qualitative analysis. This review will be based on the Critical Theory of Architecture. The evolution of the construction site occurs by the relocation and the elimination of some tasks. The partial mechanization allows workers to move, or to be moved, to less degrading jobs. However, in Brazil this is not the reason of the inclusion of machines in the processes, the major purpose is to increase productivity. Even with the incorporation of some machinery, the workers continue performing degrading jobs caused by high physical exertion required or exhaustively repetitive tasks.

L'utilisation de matériaux locaux, naturels et non transformés offre des solutions prometteuses de construction à faible impact environnemental. La grande variabilité spatiale de ces matériaux est cependant un obstacle à une utilisation à plus grande échelle. Les stratégies de construction développées par les anciens bâtisseurs ont été dictées par le climat local et la qualité ainsi que la quantité de matériaux de construction disponibles localement. Ces stratégies de construction peuvent être considérées comme une gestion optimisée des ressources locales, naturelles et variables et sont une source d'inspiration pour la construction durable moderne. Malheureusement, cette connaissance a été perdue dans les pays occidentaux au cours du 20ème siècle. La redécouverte des savoir-faire traditionnels requiert le développement de moyens rationnels d’analyse du patrimoine. Un autre problème concernant l'utilisation de matériaux de construction naturels et variables est leur conformité vis-à-vis de la réglementation du secteur du bâtiment. Le développement de procédures d’essais performantiels est proposé comme solution pour faciliter l'utilisation des techniques de construction en terre. Une approche multidisciplinaire est proposée, combinant micromorphologie, pédologie, géotechnique et étude du patrimoine pour analyser le bâti vernaculaire en terre. Cette approche fournit des outils complémentaires pour évaluer la source des matériaux de construction et identifier les caractéristiques géotechniques de la terre employées dans le patrimoine. Il fournit également une description détaillée des processus vernaculaires de construction. En utilisant ces résultats, il a été possible d'élaborer des cartes de ressources et d’estimer l’ordre de grandeur de la disponibilité des ressources à l'échelle d’une région. Deux procédures d’essais performantiels ont été proposées afin de tenir compte de la variabilité naturelle des terres dans le contexte réglementaire actuel. La construction en terre jouera un rôle important dans la construction durable du 21ème siècle si les acteurs du secteur adoptent des procédés de construction capables de répondre à la demande sociale, avec un faible impact environnemental et à un coût abordable. L'étude du patrimoine en terre a démontré la capacité des anciens bâtisseurs à innover afin de se conformer aux variations de la demande sociale et aux développements techniques. La construction en terre bénéficie d'un passé ancien et riche et il convient de tirer profit de ce retour d’expérience. L'analyse du patrimoine en terre et la redécouverte des techniques de construction vernaculaire est une source d'inspiration précieuse pour la construction contemporaine. La valorisation des connaissances vernaculaires permettra d’économiser du temps, de l'énergie et d'éviter de répéter les erreurs passées. L'avenir de la construction de la terre doit s’inscrire dans la continuité de la construction en terre vernaculaire. / The use of local, natural and unprocessed materials offers promising low impact building solutions. The wide spatial variability of these materials is, however, an obstacle to a large-scale use. The construction strategies developed by past builders were dictated by the local climate and the quality and the amount of locally available construction materials. These construction strategies can be regarded as an optimized management of local, natural and variable resources and are a source of inspiration for modern sustainable building. Unfortunately, this knowledge was lost in Western countries during the 20th century. Vernacular earth construction know-how rediscovering requires the development of rational built heritage investigation means. Another issue regarding the use of natural and variable building material is their compliance with modern building regulation. The development of performance based testing procedures is proposed as a solution to facilitate the use of earth as a building material. A multidisciplinary approach is proposed, combining micromorphology, pedology, geotechnics and heritage disciplines to study vernacular earth heritage. It provides complementary tools to assess pedological sources of construction material and geotechnical characteristics of earth employed in vernacular earth heritage. It also provides a detailed description of the construction process of vernacular earth heritage. Using these results, it was possible to draw resource maps and provide a scale of magnitude of resource availability at regional scale. Two performance based testing procedures were proposed in order to take into account the natural variability of earth in a modern building context. Earth construction will play an important role in the modern sustainable building of the 21st century if the actors of the sector adopt earth construction processes able to meet social demand, with low environmental impact and at an affordable cost. The study of earth heritage demonstrated the ability of historical earth builders to innovate in order to comply with social demand variations and technical developments. Earth construction benefits of an old and rich past and it would be a non-sense to leave this past behind. The analysis of earth heritage and the rediscovering of vernacular construction techniques is a valuable source of inspiration for modern earth construction. The valorisation of vernacular knowledge will save time, energy and avoid repeating past mistakes. The future of earth construction should be a continuation of past vernacular earth construction.

Este trabalho busca otimizar a utilização de biomassa de macrófitas aquáticas na produção de adobe (tijolos de terra crua, secos ao sol), baseado na determinação e estudo de suas características físicas e mecânicas, assim como nas características físicas e químicas destas plantas. A pesquisa foi desenvolvida no reservatório de Salto Grande, no município de Americana - SP. Este lago está localizado em uma área com déficit de habitações de interesse social, apresentando altos índices de urbanização e industrialização, o que acarreta no seu avançado processo de eutrofização artificial, decorrente das ações antrópicas. As macrófitas aquáticas predominantes no reservatório (Brachiaria arrecta, Eichhornia crassipes e Pistia stratiotes) apresentam níveis elevados de metais pesados e nutrientes (nitrogênio e fósforo), o que torna inviável sua utilização como forragem ou fertilizante. A utilização desta biomassa em materiais de construção é aqui apresentada como uma alternativa de manejo integrado do lago, na forma de encapsulamento (ou solidificação / estabilização) destas substâncias químicas, além de possibilitar a autoconstrução de habitações de baixo custo. Uma outra função do uso da biomassa no adobe é a estabilização do solo, que apresenta alto teor de argila (59 %, com 21 % de silte e 20 % de areia, classificado como A-7-6 HRB) e sofreria grandes retrações durante o processo de secagem, com surgimento de fissuras excessivas e conseqüente redução de resistência mecânica dos tijolos. A adição da biomassa contribuiu com a redução destas fissuras e da massa específica dos tijolos. Os resultados demonstraram ser esta utilização perfeitamente viável, com expressiva retirada de biomassa (juntamente com os metais e nutrientes) do sistema, além de significativas melhorias na qualidade do adobe, tanto físicas como mecânicas. Em linhas gerais, Eichhornia crassipes se mostrou a mais eficiente neste aspecto. Além de tudo, os resultados da pesquisa mostram que, apesar do adobe ser talvez o mais antigo material de construção manufaturado, sua aplicação se mostra perfeitamente viável, numa perspectiva mais ampla de sustentabilidade, se apresentando como um material completamente ecológico e adequado para regiões tropicais. / This work intends to optimise the utilization of aquatic macrophyte biomass in the adobe (a sun-dried mud brick) production, based on the study of the physical and mechanical characteristics of these bricks and the macrophytes biomass estimate as well as their chemical characteristics. The research was developed in the Salto Grande Reservoir region, in Americana (a town in São Paulo State, Brazil). This lake is located in an area of high urbanization and industrialization level, with common dwelling deficit, which is in advanced artificial eutrophication process by human activity action. The aquatic macrophytes found in that place (Brachiaria arrecta, Eichhornia crassipes and Pistia stratiotes) present a high level of heavy metals and nutrients that make impracticable their utilization as forage or fertilizer. The biomass utilization in the construction of materials appears here as an alternative of integrated management of the lake in the stabilization/solidification (or “encapsulation”) of these chemical substances, in addition to the fact that it makes possible the self-building of low cost dwellings. The other biomass function is to stabilize the soil that has a high clay concentration (59%, with 21% silt and 20% sandy) and would suffer a large drawing back during the drying process, with the introduction of excessive fissures. This biomass addition was made to reduce these fissures and the specific mass of the bricks. Besides, the research results show that, even though the adobe bricks are perhaps the oldest manufactured building material, their application persists practicable mainly in the sustainability hopes for being a completely ecological building material and adequate for the tropical regions.