Transporte de cloretos em concretos com adições minerais e o desempenho em relação à corrosão das armaduras
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2016-12-16
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Universidade Federal de Goiás
Resumo
The introduction of wind energy into the brazilian energy matrix is of paramount importance for
national energy policy. In this context, the viability of wind towers is a fundamental issue. In
Brazil, these towers are built mainly in reinforced concrete, in regions of high aggressiveness
(coastal regions, because of their greater wind potential) and, therefore, it is necessary to develop
high performance concretes that are able to withstand environmental actions to which they are
subjected, mainly the action of the chlorides, so that these structures reach the previously defined
project life, thus guaranteeing the viability of the towers. In this sense, the present work evaluates
the mechanical properties, the mechanisms of transport of chlorides and the performance in
relation to the corrosion of the reinforcement, in concretes that contain high performance pozolanic
mineral additions, in order to evaluate the influence of the presence of these additions in these
properties. Three different study mixes were developed containing respectively, 9% of silica fume
in composition with 1% of nanosilica, 5% of a high fineness metakaolin in composition with 5% of
a slightly less fine metakaolin, both with high pozzolanic activity and a mix containing only 10%
of the finest metakaolin, in addition to a reference mix. Analyzes related to the chloride transport
are presented: penetrability and diffusion; analyzes related to the corrosion of reinforcement:
induction of corrosion by aggressive solution wetting cycles and air drying, surface electrical
resistivity of concrete and corrosion potential, besides the mechanical characterization. The
concretes with incorporation of pozzolanic addition showed, in general, improvements in the
mechanical properties. In the chloride transport properties and corrosion performance of the
reinforcements, the improvements from the mineral additions were significant. Thus, it was
concluded that the incorporation of the different mineral additions studied in the present work
significantly altered the properties of the concrete, with a positive highlight for the properties
associated with durability, in which the benefits of using mineral addition are more pronounced.
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MIZAEL, A. M. Transporte de cloretos em concretos com adições minerais e o desempenho em relação à corrosão das armaduras. 2016. 166 f. Dissertação (Mestrado em Geotecnia, Estruturas e Construção Civil) - Universidade Federal de Goiás, Goiânia, 2016.