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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/11935

Title: 混凝土再鹼化及其影響之研究
Realkilization and Its Effects on Carbonated Concrete
Authors: 張建智;葉為忠
Contributors: NTOU:Department of Harbor and River Engineering
Keywords: 混凝土;碳化;再鹼化
Date: 2001-08
Issue Date: 2011-06-29T01:37:14Z
Publisher: 行政院國家科學委員會
Abstract: 摘要:本研究旨在針對已遭受二氧化碳污染之混凝土,探討在各種試驗條件(如外加電流密度、通電時間)下對於鋼筋腐蝕情況以及力學性質之影響。研究項目分下列幾項:(1)利用滴定儀滴定鋼筋界面處的混凝土粉末,以獲得pH值變化;(2)利用開路電位法與直流極化法獲得腐蝕電位以及腐蝕速率;(3)待再鹼化完成後進行抗壓強度與彈性模數試驗;(4)以單筋拉拔試驗獲得握裹強度。在分析數據上,吾人使用外加電流密度與通電時間相乘定義為影響參數ψ,利用影響參數與各項試驗結果繪製成圖而找出回歸方程式,利於分析結果。試驗結果顯示,再鹼化後混凝土孔隙水溶液的pH值會隨著影響參數ψ的增大有顯著回升至11.0以上,同時,再鹼化寬度範圍也逐漸擴大。抗壓強度、彈性模數以及握裹強度都會與影響參數ψ呈一線性之關係並且三者斜率都為負值。影響參數ψ到達807A-days/cm/sup 2/時,則腐蝕電位將由-596mV(SCE)提高至-120mV(SCE),腐蝕發生的機率將由 90﹪以上降至 10﹪以 下;而抗壓強度、彈性模數與握裹強度都高於控制組(齡期 64 天)。若影響參數ψ 高於 1,335 .mu.A-days/cm/sup 2/ 時,則腐蝕速率將由 0.111mpy 降至 0.046mpy 以下,腐蝕狀況將可達忽略不計的程度,同時抗壓強度、彈性模數與握裹強度都高於控制組(齡期 64 天)。
abstract:In this study, the electrochemical realkalisation technique is evaluated. For a carbonated concrete, we study what effects will the applied current density and realkalisation time have on corrosion prevention and mechanical behaviors. Several experiments have been conducted including the followings: (1) using chemical titration test to obtain the pH value nearby the concrete-rebar interface; (2) using the open circuit polarization method and the linear DC polarization method to obtain the corrosion potential and instantaneous corrosion rate; (3) performing mechanical tests to obtain compressive strength and elastic modulus after realkalisation; (4) performing single-rebar pullout test to evaluate the bond strength after resalkilisation. In data analysis, we define a influencing parameter ?r , defined as the product of cathodic current density and realkalisation time, then the regressive curve between this influencing parameter and testing results can be obtained. The pH value of pore solution apparently increases to a value of 11, which is the margin of forming a stable the margin of forming a stable passive film on rebar, as increasing .psi.value. Compressive strength, elastic modulus and bond strength have linear relationships with respect to .psi., the slopes are all negative. Test results show that the corrosion potential enhances from ?V596 mV(SCE), a 90% corrosion probability, to ?V120 mV(SCE), a 10% corrosion probability, when the influencing parameter .psi. achieves 807 A-days/cm/sup 2/. And at meanwhile, compressive strength, elastic modulus and bond strength are all higher than the control specimen at age of 64 days. If .psi. is higher than 1,335 .mu.A-days/cm/sup 2/, the instantaneous corrosion rate will decreases from 0.111 mpy to 0.046 mpy, that means the corrosion is negligible.
Relation: NSC90-2211-E019-013
URI: http://ntour.ntou.edu.tw/ir/handle/987654321/11935
Appears in Collections:[河海工程學系] 研究計畫

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