Utilização da microscopia eletrônica de varredura (MEV) para avaliação da ação de cloretos em compósitos de matriz cimentícia

Abstract

Currently one of the problems encountered in the corrosion of structures in reinforced concrete is related to the action of the chloride ions on it. This, in turn, acts in the depassivation of a thin protective layer that the paste, highly alkaline Portland cement, forms on the steel. The incidence of this pathological manifestation has returned the interest of scientific research to propose solutions to reduce the permeability of concrete to such deleterious agents. One justification in this sense is the demand for more durable materials, that is, those that perform their functions recommended in project, with due efficiency throughout its life cycle, aiming at also environmental sustainability. This requires not only that the materials are designed correctly, but also that the use of raw materials and processing media as well as their maintenance are appropriate. One of the routes for penetration of chlorides into the cement paste is by means of a pore stricture of the interconnected type. In this sense, the present work has as objective to present different solutions, according to the analyses of studies published in journals Qualis A1, that deal with the migration of chloride ions. As a tool to characterize the microstructure, all the articles featured the scanning electron microscopy technique to present and discuss the presented results.