Programa de Pós-graduação em Geotecnia, Estruturas e Construção Civil
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Navegando Programa de Pós-graduação em Geotecnia, Estruturas e Construção Civil por Por Orientador "Carasek, Helena"
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Item Estudo da resistência de aderência à tração e ao cisalhamento de revestimentos de argamassa em substratos de concreto(Universidade Federal de Goiás, 2014-09-25) Campos, Marina de Oliveira; Vargas, Carlos Alberto Lauro; http://lattes.cnpq.br/3816106720170772; Carasek, Helena; http://lattes.cnpq.br/3023241186996790; Carasek, Helena; Cascudo, Oswaldo; Masuero, Angela Borges; Silva, Angelo Just da Costa eBond is the crucial property of a rendering system. It is the combining result of several mortar and concrete substrates`s properties. Then, isolated studies about this subject, with single variables are insuficient. The ideal perfect understanding of the stresses, of the materials and of the tensile and shear bond sthength properties can lead to advances in the rendering system`s quality. Most of the stresses acting in rendering systems are shear stresses and, however, there is a large gap in shear bond strength knowledge. There is no standard method for the evaluation of this property. Thus, the main objective of this dissertation is to propose a laboratory method to evaluate the shear bond strength of rendering mortar in a rendering system, by the adaptation of the standartized method ASTM D 3080, used for direct shear tests in soil. Furthermore, this study aimed to evaluate the substrates`s characteristics (water cement ratio and surface roughness) and the rendering mortar`s characteristics (mix proportion) in the tensile and shear bond strength, along with doing the correlation between the two properties. In order to do so, the experimental programme included studies of tensile bond strength (Rat), using the ABNT NBR 13528 and shear bond strength studies (Rac), using the ASTM D 3080 adaptation. To the Rat tests it was prepared 10 concrete substrates that was coated with rendering mortar with 3 mix proportion (1:2:9, 1:1:6 and 1:0,5:3,4). For the concrete substrates, it was varied the water cement ratio (0,35, 0,50, 0,65 and 0,80) and the surface roughness (a smooth R1 and a roughened R2 one). For the Rac studies it was prepared 160 concrete substrates, with a smaller dimension, using the water cement ratio of 0,65. In the Rac tests the studied variables were the surface roughness (R1 and R2), the mortar mix proportion (1:1:6 and 1:0,5:3,4) and the applied normal tension (0,01 MPa, 0,06 MPa, 0,09 MPa and 0,15 MPa). Besides, it was performed an extensive characterization of the rendering mortars and the substrate`s concrete. As conclusions, the research proved that the proposed shear bond method for rendering mortar was apropriate, with low deviation coefficient of the results (6%) and with sensibility to the imposed variables (diferent mortars and substrates). The mortar mix proportion and the roughness surface of the substrates do influence in Rat and Rac, and the first one is the most influent one. The water cement ratio of the substrates concrete also influences the Rat. Besides, it was found a logarithmic correlation between Rat and Rac, with R2value of 0,87.Item Diretrizes com base em avaliação do ciclo de vida para redução de emissões de dióxido de carbono em revestimentos de argamassa(Universidade Federal de Goiás, 2013-08-27) Gama Junior, Antônio Claret de Almeida; Brandstetter, Maria Carolina Gomes de Oliveira; http://lattes.cnpq.br/8038795637292636; Carasek, Helena; http://lattes.cnpq.br/3023241186996790; Carasek, Helena; http://lattes.cnpq.br/3023241186996790; Cascudo, Oswaldo; Teixeira, Denílson; Sposto, Rosa MariaSustainable development is a highly discussed reality in world’s context. Related to that, it can be said that it is about respect with nature during economy and society development of a certain region. If so, with the growth of civil construction and industrialization of today’s world, each time growth atmospheric emissions, solids and liquids, harm the environment and causing damage to the greenhouse effect caused mainly by increasing the concentration of carbon dioxide in the atmosphere. Thinking about the impact caused by those emissions was created the tool of Life Cycle Assessment, which is capable to measure all emissions involved in services and materials life cycle. Using this tool in civil construction, specifically in the service of internal mortars, this paper aimed in making a comparison between two materials emissions of CO2, which are alternatives able to make the internal mortar, the regular mortar prepared in site and industrialized mortar. Going through the process of obtaining data along industry and sellers, and making a data collect about mortar consumption inside two constructions in the city of Goiânia, was possible do set the comparison, getting the conclusion that despite being highly industrialized, the industrialized mortar shows a better performance with regard to CO2 emissions, ie, emits a lower amount of gas to achieve the same service. Part of the explanation for that is the logistic adopted for using industrialized mortar, which requests a change in the using process. It is also possible to realize that the better performance toward regular mortar is due the high consumption of electricity needed to use this, making the Brazilian energy matrix responsible for a large amount of carbon dioxide emissions in the atmosphere.Item Avaliação da substituição total de areia natural por RCD em revestimentos de argamassa(Universidade Federal de Goiás, 2016-05-31) Girardi, Aline Crispim Canedo; Carasek, Helena; http://lattes.cnpq.br/3023241186996790; Carasek, Helena; Brandstetter, Maria Carolina; Silva, Vanessa SilveiraAlthough the use of CDW in the aggregate production is studied in Brazil for more than two decades, there are still gaps regarding their use in mortars. In this sense, the present study aims to evaluate mortar for rendering masonry produced with full replacement of natural sand by recycled aggregate, seeking to correlate the various properties and characteristics of aggregates and mortars with the performance of rendering with regard to the adhesive strength and absorption/water permeability. For the development of the research three types of aggregates were used (natural sand, mixed recycled ceramic and cement and cementitious recycled) in two particle sizes, passers-by screens 3 mm and 1.18 mm, which were widely characterized. With the data obtained in the characterization of aggregates, different traces were formulated for mortars, keeping fixed the content of total fine plasticizers. The mortars were evaluated on their consistency, bulk density, dimensional instability (shrinkage), water absorption, compressive and flexural strength. The renderings were applied on ceramic blocks, which were selected for initial water absorption rate ranges, avoiding the variability of results due to changes in the suction of the substrate. Two types of preparation of the base were performed, lime solution and roughcast, the latter was used only for the rendering that showed the best performance among those produced with recycled aggregates. As the main results, it was found that using a sieve with an opening of 1.18 mm is effective for reducing the content of fine aggregate, however, mortars and renderings produced with these aggregates showed unsatisfactory performance, falling short of results in materials with through 3 mm sieve. Mortars and rendering produced with recycled aggregate cement did not show compatible performance with the others, at the expense of the initial assumptions, which provided that this aggregate would exceed the aggregate mixed. It was also noticed that the recycled aggregates mixed ceramic and cementitious material, passers the sieve 3 mm, despite the high content of fine and high water absorption, resemble very to the natural aggregate with the same granulometry, when comparing the characteristics of mortars they have produced, mainly for resistance to compression. When assessing the rendering produced by these two aggregates, both are equivalent in the question of adhesive strength and showed no cracking. In general, it can be concluded that it is feasible the production of efficient rendering with complete replacement of natural sand for mixed recycled aggregates since the RCD origin and characteristics are known, Provided that limited the packing factor of grain , which directly influence the properties of mortars and renderings.Item Reabilitação em edifícios e monumentos art déco – métodos de avaliação dos revestimentos de fachadas(Universidade Federal de Goiás, 2013-08-22) Munduruca, Elianne Auxiliadora Moreira Borges; Carasek, Helena; http://lattes.cnpq.br/3023241186996790; Carasek, Helena; Cascudo, Oswaldo; Velosa, Ana LuisaFacade rendering perform various functions in buildings and monuments including aesthetic features, durability and economic value. However, over the years, the works begin to suffer deterioration processes, either natural or caused by unsuccessful intervention actions that trigger the onset of problems in the building rendering works, impairing these functions. In the case of historical buildings and monuments, the situation is even worse, because of the lack of knowledge of materials and techniques employed in implementing them at the time of construction. Thus, this thesis aims to study the most suitable methods for the inspection of works on facades and monuments of historical value and, from this research, aims to adapt a simplified methodology for the assessment of pathological manifestations of renderings, especially in art deco construction style built in Goiânia. To achieve this goal, was designed a case study in the Clock Tower, an important art deco monument of the capital of the Brazilian state of Goiás, has been proposed the following methodology: visual inspection for research and mapping of pathological manifestations present at the monument; photographic documentation; essay by percussion, to assess the state of rendering adhesion; application of the infrared thermograph technique; and also testing by pendulum sclerometry to evaluate the surface hardness of the rendering. As a result, it was found that the monument is deteriorated with the presence of various defects in the rendering, especially with a high cracking and dirt stains, and rust stains and disintegration. The south and north views of the tower are those most committed while in the west and east views, especially in the latter, the rendering is still in good condition.