Resumo

VELAZQUEZ-GONZALEZ, R. et al. Electrochemical Evaluation of the Corrosion Grade in Reinforced Steel in the Presence of Admixtures. Port. Electrochim. Acta [online]. 2005, vol.23, n.1, pp.179-194. ISSN 0872-1904.

In the present paper we have carried out a study in order to determine the grade of corrosion affectation in concrete structures reinforced by the incorporation of additives, using electrochemical techniques and analyzing the respective effect on their mechanical properties. Quantitative and qualitative determination of their properties has been done (chemical analysis of the additives and steel, resistance to the compression, and flexural strength, porosity, and water permeability). The methodology was carried out according to ASTM standards and the action of the admixtures was evaluated using corrosion potentials and corrosion rates. The carbonatation and penetration of chlorides were also determined. The study was supplemented with a morphologic characterization by means of a scanning electron microscope. Specimens with and without reinforcement were elaborated, three of each being tested in order to obtain an average. Prismatic specimens without reinforcement were also casted with the following chemical additives: air-entraining, plasticizers, retardants, accelerating, coloring and fly ash. After curing, they were exposed to an aggressive atmosphere with sodium chloride. The general performance of the specimens after the period of exposition is good, since practically all of them developed very low corrosion rates, between 0.55 × 10^-4 and 4.76 × 10^-4 mA/cm².

Palavras-chave : corrosion; admixture; reinforcement; electrochemical; chlorides.

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