Análise da penetração de cloretos no concreto armado expostos em ambiente natural e simulado

Abstract

Rebar corrosion is a common pathology in reinforced concrete. One of the more worrisome ways this pathology presents itself is with the penetration of chloride ions in the concrete cover layer, due to the rapid loss of the rebar cross-section to corrosion in this situation. This study presents an analysis on the penetration of chloride ions in reinforced concrete exposed to the natural sea environment, varying the distance in relation to the sea between the specimens, the resistance class with changes in the materials used and their exposition situations, after 16 weeks of exposition. It also presents an analysis on concrete inside a closed chamber filled with a 10% concentration saline solution, after 4 weeks of exposition. The analysis used three tests: superficial electrical resistivity, colorimetry with aspersion of silver nitrate and potentiometric titration. With that, it was possible to reveal the negative impact in the usage of low quality concrete. The results also reveal a great variety on the gravity of the exposition, even between direct sea spray region and 50 meters away from the sea, indicating problems in the simplification of exposition situations and in the use of simulated accelerated environment tests.