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No.17 (1979/03) >

Title :コンクリート中の鉄筋の発錆実験 その3―1年半および2ヶ年時点 その1―
Title alternative :Experimental Studies on Corrosion of Steel Bars in Concrete, Ⅲ ―At One and Half Year and Two Years after Embedding―
Authors :具志, 幸昌
和仁屋, 晴讙
伊良波, 繁雄
Authors alternative :Gushi, Yukimasa
Waniya, Haruyoshi / 和仁屋, 晴讙
Iraha, Shigeo
Issue Date :1-Mar-1979
Abstract :A series of experiments on corrosion of steel bars embedded in concrete has been done at the laboratory of concrete engineering of University of the Ryukyus. This is the third report of the above experiments and describes the corrosson behavior of steel in concrete at the times of 1.5 year and 2 years after embedding. This series of experiments consists of two parts. One is a study on steel corrosion in the concrete containning none to highly concentrated salt and containning it before and after hardened. The other is a case of study of the influences of the kinds and dosages of corrosion inhibitors and the effect of heating. This third report describes only the former, that is called "Experiment I". Experiment I is divided into two which consist of 16 experiments respectively. The first part of Experiment I is the case of salt dosed before hardening and contained none to high concentration. The second part is the case of slowly penetrating of salt into concrete after hardening. The experiments were planned after so called "Eperimental Design". The following articles are clarified at the times of 1.5 year and two years after embedded. (1) The first part of experiment I. a) The influence of salt contained on the corrosion of steel is still overwhelmingly strong, but it seems the effect is slightly weaken. b) A new tendency emerged that the influence of cover depth of concrete becomes distinctively stronger, because of cracking along steel bars in the test prisms which had thin concrete covers. c) There has been no corrosion detected over the steel surfaces in the concrete which has the water cement ratio of 40% and contained both 0.1% salt and twice the standard dosage of inhibitor. d) At the time of one year, maximum corroded area of steel surfaces was happened in the test prism of concrete contained 0.5% salt concentration, but the steel bars in the concrete contained 1% salt concentration have become mostly corroded at the times of 1.5 year and 2 years. e) The sudden increases of corroded areas of steel bars are found in the test prisms of thiner concrete covers and lareger water cement ratios. f) The highly inhibiting ability of the concrete of the water cement ratio of 40% has been demonstrated, but the considerable quantities of corrosion of steel bars can not be avoided in that concrete when the salt concentration becomes high. (2) The second part of Experiment I. a) The effect of salt on corrosion of steel bars has become stronger in the second part. b) The "sprayed" and "half-immersed" test prisms have increased the corroded areas of steel bars as the progress of time, but the "completely immersed" and "natural" test prisms appeared no sign of increasing of corrosion areas. c) The concrete of water cement ratio of 40% has strong corrosion inhibiting ability. At the time of two years passed, the steel bars in that concrete have not corroded yet in the second part of experiment I. d) The corrosion inhibiting agent used in this study has good inhibiting ability, but can not be stopped to corrode when the salt concentration of concnete becomes higher as the time has passed.
Type Local :紀要論文
ISSN :0387-429X
Publisher :琉球大学理工学部
URI :http://hdl.handle.net/20.500.12000/27594
Citation :琉球大学理工学部紀要. 工学篇 = Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering no.17 p.23 -47
Appears in Collections:No.17 (1979/03)

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