Recorrência de patologias em processos de ataque via cloreto em concreto armado

Abstract

The return or the induction of corrosion on the edges of areas treated in the presence of corrosion accelerator agents such as chloride ions and carbon dioxide leads to an analysis of current repair methodologies. According to Ribeiro (2009) the economic costs associated with concrete structures repairs are increasing and the incidence of failures in these interventions has increased. The corrosion occurs at the anode andcorrosion areas adjacent to it act as a cathode. While there is that electric dynamic, the areas surrounding the pathological manifestations are protected from corrosion. After running the repair, and the consequent anode elimination, the protection effect that the activity had on neighboring regions disappears, starting the corrosion (RIBEIRO, 2009). Therefore, the replacement of deteriorated concrete by another repair material, can induce the onset of corrosion in the surroundings of treatedareas, aggravated by the formation of corrosion macro cells. This paper reports the monitoring of structures, for about 12 years where the effectsof corrosion macro cells were observed, as these structures were exposed to harsh environments. We investigated the content of concrete impregnated chlorides with electrochemical techniques, as well as measuring the carbonation progress. As main conclusions we may note that in the presence of chlorides there is an acceleration on the corrosion macro cell formation; that the assays using electrochemical techniquescan not be taken separately in these studies and that the analysis parameters of both the chloride penetration, and the electrochemical assays are not well defined.