INIBIDORES DE CORROSAO: ANALISE DA EFICIENCIA FRENTE à CORROSAO DO ACO INDUZIDA POR CLORETOS E CARBONATACAO EM MEIO AQUOSO

The use of additives, corrosion inhibitors has been growing gradually, especially after the 90s, where there wasan intensification of the use of admixtures and additives in the preparation of the concrete in order to increasethe durability of structures. The present work aims to study the efficiency of different types of preventiveinhibitors on the corrosion resistance compared to chloride attack and carbonation. Exploratory tests wereperformed in solutions that simulate the composition of concrete pore for the selection of additives in theircontent optimized based on the efficiency of inhibition determined by electrochemical measurements. Thesolutions prepared for the tests was composed of calcium hydroxide (Ca (OH)2) saturated by additionof CO2 in the presence of 0.01 N (NaOH) N + 0.05 (KOH). Experiments have been used steel bars ofthe type CA-50, with a nominal diameter of 10 mm. Additives adopted in this paper to be evaluated fortheir potential use as corrosion inhibitors were: sodium nitrite, calcium nitrite, sodium molybdate, amineand tannin in amounts of 0, 1, 2.5 and 4 % (percentage by weight of the inhibitor in relation to the poresolution). After statistical analysis of variance of the results of the instantaneous rate of corrosion, proceededto choose the levels of inhibitors showed that inhibition in the midst of study, and were technically andeconomically feasible. The steel bars were determined and their efficiencies were evaluated visually usinga stereomicroscope. The final results showed that the inhibitors were evaluated that satisfactory levels ofprotection against attack by chlorides. Does not provide the same protection as the carbonation.