塩分を含むコンクリート中のCr鋼鉄筋の防食性に関する研究

Abstract

In this study corrosion resistance of Cr-bearing rebars is investigated in artificial concrete pore solutions and concrete specimens with high content of chloride ion. Artificial concrete pore solutions were saturated with Ca(OH)_2, containing NaCl of 0.27%, 1.07% and 21.4%. The pH of the solutions was adjusted at 12.5, 11, 10 and 9 by HCl, in which pitting potentials of the steels were investigated. The results of the study showed that 5Cr and 9Cr steels showed good corrosion resistance in 1.07% NaCl solutions at pH12.5 and pH10, respectively. In the case of concrete specimens, the test specimens were made installing 8 types of rebars into concrete specimens with chloride ion contents of 0.3, 0.6, 1.2, 2.4 and 24kg/m^3. The corrosion resistance of the Cr-bearing rebar was examined by measuring half-cell potential, corrosion area and weight loss up to 155 cycles of corrosion accelerated curing. The results of the study showed that the Cr-bearing rebar with Cr content of 5% and 9% exhibited high corrosion resistance when the chloride ion contents were 1.2 and 2.4kg/m^3, respectively.