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Authors
Abstract(s)
O presente trabalho aborda a história das construções vernáculas, tendo como objetivo estudar o comportamento físico e mecânico de alvenarias de pedra submetidas a altas temperaturas. Para tal, foram utilizados blocos de granito de três diferentes regiões de Portugal, Ponte de Lima, Mondim de Basto e de Povóa de Lanhoso. Os blocos foram cortados em cubos com arestas de 7 cm e caracterizados quanto à absorção de água por capilaridade, pressão atmosférica, massa volúmica, porosidade aberta e resistência à compressão. Foram utilizadas as normas europeias EN 1925:1999 (Métodos de ensaio para pedra natural determinação do coeficiente de absorção de água por capilaridade), EN 1926:2006 (Determinação da resistência à compressão), EN 1936:2006 (Determinação das massas volúmicas real e aparentes das porosidades total e aberta) e EN 13755:2008 (Determinação da Absorção de água por pressão atmosférica). O comportamento dos corpos de prova de granito a altas temperaturas foi avaliado para três patamares de exposição (20 °C, 400 °C e 800 °C) e dois modos de resfriamento: um de forma brusca, por meio de adição de água temperatura ambiente (20°C) e outro de forma natural. Foi possível avaliar que os granitos, expostos a um aumento de temperatura e choque térmico, apresentaram uma redução no módulo de deformação, além da redução da resistência à compressão. Foi observada uma relação entre as porosidades e as resistências dos granitos, o granito Póvoa de Lanhoso Azul, com menor porosidade aberta (0,61%) obteve a maior tensão de ruptura 152,35 MPa. Já o granito Mondim Basto Amarelo que obteve a maior porosidade aberta (5,47 %) rompeu com 30,5 MPa.
The present work studied the history of vernacular constructions, and the main goal is the physical and mechanical behaviour of stone masonry exposed to high temperatures. For this purpose, granite blocks from three different regions of Portugal were used from Ponte de Lima, Mondim de Basto and Povóa de Lanhoso. The blocks were cut into cubes with 7cm x 7cm x 7cm edges and characterized by their water absorption by capillarity, atmospheric pressure, volume, open porosity, and compressive strength. The European standards used were EN 1925 (Test methods for natural stone determination of the water absorption coefficient by capillarity), EN 1926 (Determination of the compressive strength), EN 1936 (Determination of real and apparent density of the total porosities and EN 13755 (Determination of water absorption by atmospheric pressure). The behaviour of granite specimens at high temperatures was evaluated for three levels of temperature exposure (20 ° C, 400 ° C and 800 ° C) and two cooling modes, one abruptly, by adding water at the ambient temperature (20 °C) and the other in a natural way. It was possible to evaluate that the granites exposed to any increase in temperature showed a reduction in the elasticity module, in addition to a reduction in the compressive strength of granites exposed to the same temperatures but received thermal shock. A pattern was observed between the open porosities and the resistances of the granites, the Póvoa de Lanhoso granite, with the lowest open porosity (0.61 %), obtained the highest compressive strength 152.35 MPa. The Mondim de Basto granite, which had the highest open porosity (5.47 %), broke with 30.5 MPa.
The present work studied the history of vernacular constructions, and the main goal is the physical and mechanical behaviour of stone masonry exposed to high temperatures. For this purpose, granite blocks from three different regions of Portugal were used from Ponte de Lima, Mondim de Basto and Povóa de Lanhoso. The blocks were cut into cubes with 7cm x 7cm x 7cm edges and characterized by their water absorption by capillarity, atmospheric pressure, volume, open porosity, and compressive strength. The European standards used were EN 1925 (Test methods for natural stone determination of the water absorption coefficient by capillarity), EN 1926 (Determination of the compressive strength), EN 1936 (Determination of real and apparent density of the total porosities and EN 13755 (Determination of water absorption by atmospheric pressure). The behaviour of granite specimens at high temperatures was evaluated for three levels of temperature exposure (20 ° C, 400 ° C and 800 ° C) and two cooling modes, one abruptly, by adding water at the ambient temperature (20 °C) and the other in a natural way. It was possible to evaluate that the granites exposed to any increase in temperature showed a reduction in the elasticity module, in addition to a reduction in the compressive strength of granites exposed to the same temperatures but received thermal shock. A pattern was observed between the open porosities and the resistances of the granites, the Póvoa de Lanhoso granite, with the lowest open porosity (0.61 %), obtained the highest compressive strength 152.35 MPa. The Mondim de Basto granite, which had the highest open porosity (5.47 %), broke with 30.5 MPa.
Description
Mestrado de dupla diplomação com a FUMEC
Keywords
Alvenaria de pedra Granito Resfriamento brusco Choque térmico