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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/12043

Title: 鋼筋混凝土在陰極防蝕電流作用下之行為研究(I)
A Study on the Properties of Reinforced Concrete under the Cathodic Protection Current (I)
Authors: 張建智
Contributors: NTOU:Department of Harbor and River Engineering
Keywords: 鋼筋混凝土;陰極防蝕;耐久性;握裹強度
Reinforced concrete;Cathodic corrosion protection;Durability;Bonding strength
Date: 2002-08
Issue Date: 2011-06-29T01:37:58Z
Publisher: 行政院國家科學委員會
Abstract: 摘要:本研究係以混凝土中添加波索蘭材料取代水泥的方式,並以電流密度及通電時間為試驗變數,利用單筋拉拔試驗法得到握裹力與位移兩者關係,藉此探討添加波索蘭材料後,陰極防蝕對握裹強度的影響,是否達到改善握裹力降低的效果。此外,輔以鈉、鉀離子在混凝土中之濃度量測與界面處微硬度實驗分析,並利用 SEM 微觀結構觀察來佐證實驗結果。研究結果顯示以波索蘭材料取代水泥之混凝土,確實對握裹強度折減的情況有抑制的效果,且隨著通電時間及電流密度的增加,其握裹力的折減效應更為明顯。除此之外,從鈉、鉀離子累積含量與硬度值試驗中,可瞭解混凝土在通電後與鋼筋界面軟化的情況,會隨著鈉、鉀離子累積含量增加而有愈嚴重的趨勢。最後利用單筋拉拔試驗所得到握裹力與位移之關係圖,求出材料參數 K 值與 qy 值及影響參數ψ值,並建立其與握裹強度之關係。
abstract:In this study, a strategy to improve the bond degradation due to a cathodically protected reinforced structure is studied. The main idea is to add pozzolans in concrete such that the bond strength degradation due to the cathodic current could be retarded. Pozzolans were added in concrete as the replacement of cement. Under various cathodic current densities and polarization periods, the bond performances of various concrete mixes were evaluated using the single rebar pullout test. Analyzing these data, the improvement of bond degradation by adding the pozzolans was investigated. In addition to the pullout test, three indirect experiments were conducted to understand the interface behaviors: (1) the chemical titration determines the accumulated potassium and sodium ions nearby the rebar-concrete interface; (2) the micro-hardness test is performed to examine the softening effect; (3) microstructure changes were examined using the back-scattering scanning electronic micrscope (SEM). The results showed that adding pozzolans in concrete could effectively reduce the bond degradation due to the cathodic current. As increasing the polarization time and/or current density, the bond degradation became more apparent. Chemical titration test and microhardness test revealed that interface softening became more apparent as the concentration of the accumulated potassium and sodium ions became higher, which indicated the bond strength became worse. A unified parameter (psi), that combines the effect of polarization time and current density, was used to study the effects of cathodic current on the three interface bond parameters.
Relation: NSC91-2211-E019-021
URI: http://ntour.ntou.edu.tw/ir/handle/987654321/12043
Appears in Collections:[河海工程學系] 研究計畫

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