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姓名 潘奕銘(Yi-Ming Pan) 查詢紙本館藏 畢業系所 土木工程學系 論文名稱 低放射性廢棄物處置場混凝土障壁材料溶出劣化效應評估
(Effects of leaching on cementitious material as barrier for low-level radioactive waste disposal)相關論文 檔案 [Endnote RIS 格式] [Bibtex 格式] [相關文章] [文章引用] [完整記錄] [館藏目錄] [檢視] [下載]
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摘要(中) 低放射性廢棄物處置場主體由混凝土構成,由於台灣處於四面環海環境下,使得低放射性廢棄物處置場可能遭受外在環境各種元素的侵蝕,處置場障壁長期處於此服務環境下,可能對混凝土造成損害或劣化甚至影響其耐久性。
本研究針對低放射性處置場所使用之水泥基材長期處於地下環境等特有環境下,以實驗室模擬水泥砂漿及水泥漿長期暴露於各種不同環境,探討溶出行為對於水泥基材長期耐久性之影響。試驗結果得知(1)不論浸泡於純水、人工海水或硝酸銨溶液之砂漿試體皆出現明顯的強度折減,其中尤以浸泡於硝酸銨溶液之試體強渡折減最為顯著;(2)隨著溶出歷時時間之增加,將降低其容積比重並使得孔隙率隨之增加,尤其又以浸泡於硝酸銨溶液中之水泥砂漿試體最為顯著;(3)由微觀分析結果顯示,水泥砂漿試體浸泡硝酸銨溶液後會加速溶出氫氧化鈣,造成試體表面之重量嚴重損失,皆由電子顯微鏡之能量分散光譜儀(SEM-EDS)、電子探微儀量及電子能譜儀所觀測之水泥漿試體皆顯示鈣含量隨深度增加而降低。
此外,運用美國國家標準署CEMHYD3D程式模擬各參數對於溶出失鈣劣化之影響,由掺料參數及水化參數結果顯示,添加卜作嵐掺料對於抵抗溶出劣化有較好之功效,在水化參數方面,隨著水化程度越高時,將降低其溶出速率。在劣化參數方面,結果顯示隨著溶出劣化程度之增加,將使得氫氧化鈣損失量持續增加。摘要(英) The engineering barrier of the proposed low-level radioactive wastes disposal calls for the use of concrete. Since Taiwan is surrounded by oceans, the low-level radioactive wastes disposal site is very likely to suffer from the attack of adverse environment. In this study, leaching of concrete material was simulated in the laboratory to evaluate the long-term durability of concrete material. The possible degradation mechanism and potential influence on the durability were carefully examined.
The results of the laboratory works show that:(1)the residual compressive strength of mortar samples immersed in ammonium nitrate solution for 3 months reduced to 38%~45% of the original compressive strength. After soaking in both pure water and ocean water environment, the residual compressive strength of mortar reduced to 75%~95% of the original compressive strength.(2)Increases in leaching duration of cement mortars resulted in decreases in bulk density and increases in porosity of mortar specimens. (3)Microstructural observations showed that mortar samples in ammonium nitrate solution experienced accelerating leaching of Ca(OH)2, and SEM-EDS and XPS analyses show that the depths of leaching observed on cement mortar specimens are found to be deeper than the cement paste specimens.
The effects of leaching on properties of cement paste were also evaluated using the simulation program developed by NIST. The addition of pozolanic material(fly ash)to cement paste mixes was found to improve the resistance of cement paste. And the higher the degree of hydration, the lower the damage of leaching on cement pastes.關鍵字(中) ★ 混凝土障壁
★ 低放射性廢棄物處置場
★ 失鈣劣化關鍵字(英) ★ low-level radioactive wastes
★ leaching
★ concrete barrier論文目次 目錄 I
圖目錄 IV
表目錄 VII
第一章 緒論 1
1.1 研究動機 1
1.2 研究目的 2
1.3 研究內容 2
第二章 文獻回顧 4
2.1 低放射性廢棄物 4
2.1.1 低放性廢棄物來源 4
2.1.2 低放射性廢棄物處置 4
2.2 混凝土耐久性 8
2.2.1 混凝土耐久性之定義 8
2.2.2 物理性侵蝕 9
2.2.3 化學性侵蝕 10
2.3 失鈣劣化 13
2.3.1 失鈣劣化之過程與機理 14
2.3.2 失鈣劣化對內部結構的影響 15
2.3.3 影響水泥漿體溶出劣化之因素 17
2.3.4 失鈣劣化深度 19
2.3.5 失鈣劣化對力學性質之影響 20
2.3.6 劣化深度預測模式 22
第三章 試驗計劃 29
3.1 實驗材料 29
3.2 主要實驗設備 33
3.3 實驗內容與方法 37
3.3.1 實驗流程 37
3.3.2 實驗變數 39
3.3.3 試驗方法 42
第四章 結果與討論 48
4.1 抗壓強度 48
4.1.1 不同配比水泥砂漿之抗壓強度發展 48
4.1.2各水泥砂漿受失鈣溶出作用之抗壓強度 51
4.2 容積比重 57
4.2.1各水泥基材在不同溶出環境中對於容積比重之影響 57
4.3 孔隙率 62
4.3.1各水泥基材在不同溶出環境對於孔隙率之影響 62
4.4 微觀分析 69
4.4.1 熱重分析(TGA) 69
4.4.2 掃描式顯微鏡之能量分散光譜(SEM-EDS) 80
4.4.3 電子探微儀(EPMA)及電子能譜儀(XPS) 87
第五章 模擬失鈣 92
5.1 NIST CEMHYD3D 模型摡述 92
5.1.1微結構的建立 93
5.1.2 CEMHYD3D水化過程 95
5.1.3失鈣模擬 96
5.2 參數分析 96
5.2.1 材料參數 98
5.2.2 水化參數 103
5.2.3 劣化參數 107
5.3 小結 107
第六章 結論與建議 109
6.1 結論 109
6.2 建議 112
參考文獻 113參考文獻 行政院原子能委員會,http://www.aec.gov.tw (2006) 。
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Young, J. F., Mindess, S. and Daewin, D. (2002), Concrete, Prentice-Hall, Inc., Upper Saddle River, New Jersey, U.S.A.指導教授 黃偉慶(Wei-Hsing Huang) 審核日期 2007-7-13 推文 facebook plurk twitter funp google live udn HD myshare reddit netvibes friend youpush delicious baidu 網路書籤 Google bookmarks del.icio.us hemidemi myshare