Estruturas de concreto armado em ambiente urbano: avaliação de carbonatação à luz das recomendações da NBR 6118:2003

Abstract

This present paper evaluates the depth of carbonation of concrete test samplers taken from existing buildings where it was possible to recover the registers of concreting such as: date of execution, concrete mixture proportions, compression resistance and design specifications allowing the establishment of the cover thickness foreseen during the design phase with the thickness of carbonation according to the exposure time. These buildings that are in Ribeirão Preto City, in the State of São Paulo had their structures designed and started in the ninety s decade under the rules and recommendations of NBR 6118:1980, specially about the protection of the steel reinforcement by the thickness of the concrete cover, and their construction stopped until the concrete test samplers were extracted for this research. The results allow of the affirmation that the depth of carbonation had already reached significant levels indicating the need of protection or structural recovery of the elements researched. Parallel there was a simulation to get to know the results in these structures using the rules of NBR 6118:2003 to cover the steel reinforcement. The conclusion was, in most cases, the steel reinforcement still had a significant protection if the parameters used were according to the recommendations of this norm, and then, light interventions were needed to restart the construction.