Agressividade ambiental em zona de atmosfera marinha: estudo da deposição de cloretos e sua concentração em concretos na Região Sudeste
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2011-03-25
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Borba Júnior, José Carlos
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Universidade Federal do Espírito Santo
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The concrete structures that are built close to the sea suffer the environmental aggression caused by the marine aerosol. The marine aerosol is a sea salt airbone formed by the ocean waves movement and by the friction of the wind against the surface of the ocean water. The quantity of salt found in the aerosol is bigger the more the winds of the region are and the less the distance from the coast is. That aerosol is transported by the wind towards the continent, and then it is deposited on the concrete surface structures. The chloride that is deposited enters into the concrete by an absorption and ionic diffusion, and may cause the corrosion of the framework. This work aims to measure the concentration of chlorides in the marine aerosol and associate it with the concentration of chloride in the concrete. To do that, five natural exposition point were selected to measure the sea salt airbone, being three of them used to expose the concrete to the environmental aggression. The points are located in the metropolitan region of Vitoria city at 60, 65, 120, 240 and 520 meters away from the sea, being the three farthest ones used to expose the concretes. The chloride measurements found in the marine aerosol was carried out by using the wet candle test. Climate measures were also taken to characterize the region under analyses. The analyzed concretes were modeled on concrete prism test specimens with different traces, varying the relation water/cement: 0,65, 055 e 0,45. After 6 and 20 months, samples of the concretes were taken to determine the chloride tenor. The results indicate a fragile relation between the deposition of chlorides in the atmosphere and the concentration of chlorides in the concrete for the analyzed region. The deposition of chlorides, in its turn, presented low correlation with the rate flow of the winds. Anyway, it is possible to establish a behavior of the environmental aggressiveness according to the obtained determinations.
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BORBA JÚNIOR, José Carlos. Agressividade ambiental em zona de atmosfera marinha: estudo da deposição de cloretos e sua concentração em concretos na Região Sudeste. 2011. Dissertação (Mestrado em Engenharia Civill) - Universidade Federal do Espírito Santo, Centro Tecnológico, Vitória, 2011.