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Advisor(s)
Abstract(s)
A terra é usada como material de construção desde o princípio das civilizações. Atualmente, estima-se que um quarto da população mundial viva em construções em terra. Entretanto, durante o século XX, o material caiu em desuso em diversos países desenvolvidos com o surgimento do betão, sendo utilizado somente em situações de vulnerabilidade. Entretanto, desde o início do século XXI, a atenção dada a esse material foi renovada, por se tratar de método ecológico, com baixo consumo energético e emissão de carbono para a execução. Dessa forma, faz-se necessária a caracterização das construções em terra. Esse trabalho tem como objetivo contribuir para a caracterização térmica de paredes de taipa, levando em consideração a variação da espessura e a escolha do solo. As amostras analisadas são provenientes de dois solos da região do Alentejo (um considerado ideal para taipa e outro enquadrado no limiar dos limites propostos na literatura). O programa experimental contou com ensaios para a caracterização física e termohigrométrica dos materiais, além do procedimento desenvolvido para a execução dos provetes. Os ensaios utilizados na caracterização termohigrométrica buscam estimar os valores do coeficiente de transmissão térmica, da condutibilidade térmica e da taxa de absorção da água a baixa pressão dos provetes. Ao analisar os resultados, constata-se que a variação da espessura da parede de taipa possui influência significativa nos valores encontrados: o coeficiente de condutibilidade térmica de um provete com 50 cm de espessura é cerca de 30% inferior ao coeficiente de um provete de 35 cm e mesmo solo. Além disso, verificou-se que o solo S1, que possui maior baridade, apresenta maior condutibilidade térmica e menor taxa de absorção da água a baixa pressão. Verificou-se também a influência da umidade no comportamento térmico da taipa. Era esperado que o solo S1 apresentasse maior valor de U. Entretanto, na altura dos ensaios, os provetes do solo S2 apresentaram o dobro da umidade de S1. Assim, apresentaram coeficiente U superior a S1: o valor de W35S1 foi de 1,53 W/m²°C, enquanto o valor de W35S2 foi de 2,43 W/m²°C. Por fim, os materiais foram enquadrados no Regulamento das Características de Comportamento Térmico dos Edifícios, de modo a ilustrar uma solução de envolvente contendo parede de taipa e argamassa de terra que cumpra os requisitos propostos.
Earth has been used as a construction material since the beginning of civilizations. Currently, is estimated that one quarter of the world's population lives in buildings made of earth. However, during the 20th century, this material fell into disuse in several developed countries with the popularization of concrete, and nowadays is being used only in situations of vulnerability in those countries. Yet, since the beginning of the 21st century, the attention given to this material has been renewed, since it is an ecological method, with low embodied energy and carbon emission for its execution. Thus, it is necessary to characterize rammed Earth constructions. This work aims to contribute to the thermal characterization of rammed earth walls, taking into consideration the variation in thickness and soil choice. The samples analyzed come from two soils in the Alentejo region (one considered ideal for being used on rammed earth and the other within the limits proposed in the literature). The experimental program included tests for the physical and thermohygrometric characterization of the materials, in addition to the procedure developed for the execution of the specimens. The tests used in the thermohygrometric characterization seek to estimate the values of the conductance coefficient, thermal conductivity and low pressure water absorption rate of the specimens. By analyzing the results, it is verified that the variation in the wall thickness of rammed earth walls has a significant influence on the results: the thermal conductivity coefficient of a 50cm thick specimen is about 30% lower than the coefficient of a 35cm specimen of the same soil. In addition, soil S1, which has higher density, higher thermal conductivity and lower water absorption rate. It was also verified the influence of moisture on the thermal behavior of rammed earth walls. It was expected that soil S1 would present a higher value of U. However, at the time of the tests, samples from soil S2 presented twice the moisture content of S1. Thus, they presented a U coefficient higher than S1: the value of W35S1 was 1.53 W/m²°C, while the value of W35S2 was 2.43 W/m²°C. Finally, the materials were compared with REH, a portuguese regulation, in order to illustrate a solution with rammed earth and earth mortar that meets the proposed requirements.
Earth has been used as a construction material since the beginning of civilizations. Currently, is estimated that one quarter of the world's population lives in buildings made of earth. However, during the 20th century, this material fell into disuse in several developed countries with the popularization of concrete, and nowadays is being used only in situations of vulnerability in those countries. Yet, since the beginning of the 21st century, the attention given to this material has been renewed, since it is an ecological method, with low embodied energy and carbon emission for its execution. Thus, it is necessary to characterize rammed Earth constructions. This work aims to contribute to the thermal characterization of rammed earth walls, taking into consideration the variation in thickness and soil choice. The samples analyzed come from two soils in the Alentejo region (one considered ideal for being used on rammed earth and the other within the limits proposed in the literature). The experimental program included tests for the physical and thermohygrometric characterization of the materials, in addition to the procedure developed for the execution of the specimens. The tests used in the thermohygrometric characterization seek to estimate the values of the conductance coefficient, thermal conductivity and low pressure water absorption rate of the specimens. By analyzing the results, it is verified that the variation in the wall thickness of rammed earth walls has a significant influence on the results: the thermal conductivity coefficient of a 50cm thick specimen is about 30% lower than the coefficient of a 35cm specimen of the same soil. In addition, soil S1, which has higher density, higher thermal conductivity and lower water absorption rate. It was also verified the influence of moisture on the thermal behavior of rammed earth walls. It was expected that soil S1 would present a higher value of U. However, at the time of the tests, samples from soil S2 presented twice the moisture content of S1. Thus, they presented a U coefficient higher than S1: the value of W35S1 was 1.53 W/m²°C, while the value of W35S2 was 2.43 W/m²°C. Finally, the materials were compared with REH, a portuguese regulation, in order to illustrate a solution with rammed earth and earth mortar that meets the proposed requirements.
Description
Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
Keywords
Construção em terra crua Taipa Caracterização termohigrométrica