障壁混凝土受氯離子入侵剖面及使用年限推估之方法比較

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Title:	障壁混凝土受氯離子入侵剖面及使用年限推估之方法比較
Authors:	彭琦茵;Peng,Qi-in
Contributors:	土木工程學系
Keywords:	混凝土;氯離子入侵;使用年限推估
Date:	2015-01-23
Issue Date:	2015-03-16 15:08:05 (UTC+8)
Publisher:	國立中央大學
Abstract:	低放射性廢棄物最終處置場工程障壁主要由混凝土所構成，但不同於一般結構物之混凝土用途，考慮放射性衰退至不影響人類生活，障壁混凝土的使用年限需達數百年。台灣四面環海的環境，場址可能位於濱海環境，恐受到海水中的氯離子入侵，混凝土使用年限的推估即為重要探討議題。本研究針對可能使用於障壁混凝土之高完整性容器配比HIC(High Integrity Container)，製作混凝土試體，以AASHTO T259試驗方法將混凝土以氯化鈉水溶液浸泡，模擬混凝土受單方向氯離子入侵，並以AASHTO T260量測不同浸泡時間之氯離子濃度剖面，將實驗數據代入費克第二定律，求得擴散係數與表面氯離子濃度值，並以實驗數據計算擴散係數隨時間增加而降低之速率(時間因子m值)，推算長時間擴散係數的變化及表面氯離子濃度的變化，求混凝土受氯離子入侵之使用年限。 Life-365程式為ACI所發展，用於濱海環境受氯離子入侵之鋼筋混凝土服務年限推估程式。以Life-365推估模式，分析其重要參數的敏感度，得知卜作嵐材料的用量對於鋼筋混凝土服務年限的影響最大。本研究即利用Life-365推估模式，引進配比HIC材料參數，包括擴散係數D、時間因子m以及表面氯離子濃度CS，推算配比HIC於1年、2年、3年及4年的濃度剖面，與實驗數據比較，推估模式與量測結果接近，以此模式推估配比HIC之使用年限，假設於混凝土障壁澆注完成後，即接觸到氯離子環境，以及可能於混凝土製作完成多年以後才受到氯離子環境，使用年限皆可達1000年以上。 ;The barriers of facilities which dispose wastes with low radioactivity are mainly composed of concrete. But unlike the normal purpose of concrete, the barrier concrete is expected to be used for more than several hundred years. However, due to Taiwan’s geographic feature, the site of such facilities is likely to be placed in marine environment, which will cause immense influences on the degradation and durability of concrete over a long period of time. In this study, concrete specimens made with mixture possibly used for fabricating high integrity containers or engineered barrier, called HIC, were subjected to chloride ion penetration in one direction. Based on AASHTO T259 test method, the specimens were immersed in NaCl solution and measurement of chloride ion concentration profile at different soaking durations was conducted according to AASHTO T260. Then, Fick’s second law was used to obtain chloride diffusion coefficient and surface chloride content from non-linear regression.. Developed by ACI, Life-365 program predict the service life of the reinforcement concrete structures invaded by chloride ion in marine environment. For Life-365 prediction, the content of pozzolanic materials is a major parameter affecting the service life. In this study, we predict service life referring to Life-365 prediction model and determine material parameters, including diffusion coefficient, diffusion reduction, and increasing model of surface chloride content, using experimental results. Assuming that chloride ions invade into concrete early after curing, the service life of HIC mixture is estimated to be over 1000 years.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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