Study of the Addition of Air‑Entraining Polymer as an Alternative to Reduce the Progress of Carbonation in Concrete Structures

Resumo

Carbonation is one of the main degradation mechanisms of reinforced concrete, as it reduces the material’s pH and promotes the depassivation of the reinforcement, compromising the durability of structures. In this context, the use of air‑entraining admixtures can be an alternative to modify the porous structure of concrete, potentially influencing the progression of carbonation. This study evaluated the influence of an air‑entraining polymer on the advancement of concrete carbonation. Specimens with and without the polymer were cast, subjected to dry curing for 28 days, and then exposed to an accelerated carbonation chamber. Afterward, the samples were removed from the chamber at 7, 14, 21, and 28 days of exposure, longitudinally sectioned, and sprayed with a 1% phenolphthalein solution. The results indicated complete carbonation in both concretes, as well as very similar void ratios, with differences below 1%. No significant influence of the air‑entraining admixture on limiting carbonation progression was observed under the conditions studied.