Contribuição para o estudo da realcalinização em concreto por meio de método eletroquímico

Abstract

One of the most recurrent pathological manifestations in reinforced concrete structures is corrosion, which has elevated repair costs. Resulting in a concrete pH change from alkaline to neutral, carbonation is one of the causes of the presented pathology. The process happens through chemical reactions consuming alkaline substances in the cement paste. Since an alkaline concrete pH promotes chemical inertia in steel and the formation of a passive layer, a decrease in its levels jeopardizes the reinforcements, subsequently increasing corrosion speeds. Therefore, techniques that aim re-establishing a basic pH in concrete are essential to ensure the durability of concrete structures. Replacing affected concrete is effective for this purpose, however, when envisioning environmental issues, non-destructive techniques, such as chemical realkalisation and electrochemical realkalisation, become more profitable alternatives. In this research, an electrochemical realkalisation method was applied to carbonated beams, using chemical realkalisation along with two different metals as anodes: titanium and aluminum. Compared to chemical realkalisation, the electrochemical method used displayed greater reduction in carbonation depth measurements. It was possible to determine quantitatively that the titanium metallic mesh presented the best results. Nonetheless, at the end of this paper, several suggestions for future studies are presented based on the achieved results and the experience in assembling an electrochemical realkalisation cell.