| 種別 | paper |
| 主題 | The Effect of Cover Thickness and W/C Ratio on Corrosion of Steel in Concrete |
| 副題 | |
| 筆頭著者 | Kazuo SUZUKI （Osaka University） |
| 連名者1 | Yoshiteru OHNO （Osaka University） |
| 連名者2 | Somnuke PRAPARNTANATORN （Osaka University） |
| 連名者3 | Hiroshi TAMURA （General Building Research Corporation） |
| 連名者4 | |
| 連名者5 | |
| キーワード | |
| 巻 | 11 |
| 号 | 2 |
| 先頭ページ | 625 |
| 末尾ページ | 630 |
| 年度 | 1989 |
| 要旨 | INTRODUCTION Under uniform environment,corrosion of steel in concrete may undergo microcell actions. For members subjecting to nonuniform environment, some steels are in active state (anode) comparing to the other (cathode).Corrosion of these members will undergo macrocell actions. Therefore, concrete cover has to provide two simultaneous roles for corrosion protection. The obstruction of the ingress of anodic activators such as chloride is the first important role. The second one is to resist the penetration of oxygen, which is an essential substance for cathode reactions of both microcell and macrocell corrosion.The research aims to clarify the effect of cover thickness and water to cement ratio (W/C) of concrete on both macrocell and microcell corrosion.In the investigation of macrocel actions, anode (mild steel in NaCl contaminated concrete) was seperated from cathode (stainless steel in plain concrete).One steel bar was embedded in prism specimens in order to investigate the progress of microcell corrosion, i.e.from passive to active states. Conclusions (1) Both W/C and cover thickness have effects on the progress of microcell corrosion.(2) Under macrocell actions and wetting & drying environment,W/C of concrete over cathode steel has more effect on anode dissolution than cover thickness has .(3) The polarity reversal was observed in the experiments .The results strongly suggest that oxygen concentration should play a major role on macrocell corrosion. In other words,the oxygen rich steel will become cathode of the cell regardless of how much chloride content is.(4) A limitation of iron dissolution of steel in concrete was found. The effect of W/C ratio on iron dissolution was more pronounced in group of specimens with smaller cathode size. For 0.70 W/C,the effect of cathode size can not be seen . |
| PDFファイル名 | 011-01-2105.pdf |