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No. 20 (1980/09) >

 
Title :コンクリート中の鉄筋の発錆実験 その8 -実験6 塩分量の少ない場合 その2-
Title alternative :Experirental Studies on Corrosion of Steel Bars in Concrete, 8 -Experiments 6, In Case of Small Dosage of Salt, 2-
Authors :具志, 幸昌
和仁屋, 晴讙
伊良波, 繁雄
Authors alternative :Gushi, Yukimasa
Waniya, Haruyoshi
Iraha, Shigeo
Issue Date :Sep-1980
Abstract :This is the second report of the results of experiments, named Experiments 6, which aims to determine the threshold values of NaCl concentrations in concrete for steel bar rusting, where corrosion inhibitors exist in concrete. In Experiments 6, there have been small dosages of NaCl in concrete specimens and corrosion inhibitors are also dosed in some specified values. The following results about steel bar rusting are obtained when 12 months have passed after steel bars had been embedded into concrete. 1. There have been found very small rusting spots on one bar at nine and twelve months after embedding, respectively. The bars above are embedded in the concrete of 0.033% NaCl dosage and no corrosion inhibitor. 2. There have been no sign of corrosion on the surface of the bars in the specimens contained 0.033% NaCl and the specified values of corrosion inhibitors. 3. Steel bars in the concrete contained 0.067% of NaCl by weight do not also corroded yet except one bar, where adequate amounts of corrosion inhibitors are added into the concrete. 4. In case of the standard specified dosage of corrosion inhibitors, there have been some amounts of rusting areas on steel bar surfaces embedded in the concrete of 0.100% NaCl concentration, and appreciable amounts of corrosion areas of rusting in the concrete of 0.133% NaCl concentration. The above rusting areas have both increased as the time has passed. 5. Two-fold dosage of corrosion inhibitors in concrete has significant effects on inhibiting corrosion of steel bars in the concrete of 0.100% and 0.133% NaCl concentration, but in that case, emergence of steel bar corrosion itself can not be interrupted. 6. There can be said at the time when one year has passed after embedding steel bars that "threshold" value of NaCl concentration in concrete on rusting of steel bars is 0.067% by weight of concrete where adequate amounts of corrosion inhibitors exists, and that the value can be raised as much as 0.100%.
Type Local :紀要論文
ISSN :0389-102X
Publisher :琉球大学工学部
URI :http://hdl.handle.net/20.500.12000/17688
Citation :琉球大学工学部紀要 no.20 p.35 -41
Appears in Collections:No. 20 (1980/09)

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