Análise da vida útil residual de elementos de concreto armado em edificações urbanas - estudo de caso

Abstract

The carbonation of concrete is one of the pathological manifestations of predominant occurrence in urban environments, due to the presence of carbon dioxide. If not identified and treated, this might cause the loss of buildings lifespan. The present study has as objective to analyze the advance of the carbonation in pillars of three buildings located in the city of Porto Alegre – RS, verifying the residual lifespan of the buildings, regarding the depassivation of the steel reinforcement. It is pertinent to highlight that the edification 01 is located by the highway BR 116, and the avenue “Avenida dos Estados”, places of intense traffic, and buildings 02 and 03 are in the neighborhood “Moinho dos Ventos”, constituted by clinics, medical practices, and corporate buildings, that also bring a high vehicle flux. To collaborate in the understanding of the hypothesis, a broad theoretical review was described, and, using it, the problems and alternatives were elicited. To identify the carbonation advance in the building's pillars, a colorimetric analysis was employed using the chemical indicator of hydrogen-ionic potential, via dust collection method of the concrete structures. Possessing the carbonation advance, the lifespan of the buildings was estimated using theoretical methods. The results have shown that the studied buildings had carbonated surfaces, reinforcement coating under the ideal referred in the standards and, in addition, elements with terminated lifespan. It is possible to notice in the different inspected elements the influence of the environmental class of aggressiveness in the face of damage. It was also verified a non-conformity of the coating with the standards proposition. Thus, it is suggested higher attention in the phases of project, execution, use, as well as the recuperation of some elements aiming to extend the lifespan and the safety of use and operation.