活性粉混凝土應用於低放射性廢棄物最終處置場工程障壁材料之耐久性評估

莊美玲(Mei-ling Chuang)

指導教授 ： 黃偉慶

國立中央大學/工學院/土木工程學系/博士(2014年)

摘要

本研究利用活性粉混凝土(Reactive Powder Concrete, 簡稱RPC)為處置場工程障壁材料，利用試驗結果研判試驗變數對於耐久性影響程度，針對可能遭遇各種環境侵襲，進行耐久性長期試驗；而影響耐久性因素應同時考量使用之材料，並與混凝土試體變數間比較，以提升混凝土品質延長使用年限，以期達到低放處置場服務年限。
研究結果著重於建立活性粉混凝土耐久性成效之量化分析方法，對延長服務年限及提高工程障壁之信賴度，以期達到預期之成效。經浸泡硫酸鹽溶液之混凝土角柱經12個月期間觀察，添加鋼纖維之試樣長度變化量明顯降低，顯示添加鋼纖維並未因表面腐蝕造成膨脹現象，並發現水膠比之增加對抵抗硫酸鹽侵蝕能力較低。氯離子入侵濃度分析結果發現活性粉混凝土低水膠比及添加卜作嵐礦物摻料，使其內部結構較緻密，氯離子擴散係數較小，但氯離子會持續累積於混凝土表面，造成表層(約20 mm處)氯離子濃度較高，研究主要以擴散係數、孔隙率、孔徑分布判定活性粉混凝土抵抗外來物質入侵之能力。

關鍵字

活性粉混凝土 ； 耐久性 ； 工程障壁

並列摘要

Reactive powder concrete (RPC) has been proposed as barrier materials for the construction of engineered barrier in Taiwan. The durability characteristics of RPC in such applications become paramount for the success of the containment of the wastes. The adverse environmental conditions at the disposal site could attack concrete barrier material and results in degradation of the material. Laboratory tests were conducted on RPC with various compositions to investigate the physical and engineering characteristics of RPC. In this study, curing of specimens at elevated temperature of 80℃ accelerated the hydration processes of concrete and thus exhibited higher compressive strength. However, it is accelerated the hydration processes of concrete and thus exhibited higher compressive strength. The resistance of concrete to sulfate attack were tested by submerging RPC specimens submerged in Na2SO4 solution. Based on the volume change data in 12 months, specimens without steel fiber showed greater length changes than those with steel fiber. Also, RPC with higher water to binder ratio (W/B) exhibited lower resistance to sulfate attack. According to the test result, the internal structure of RPC having low W/B and blended with pozzolanic materials is comparatively denser, leading to the low diffusion coefficient under the attack of chloride ions. Bonded chloride ions may constantly accumulate at the surface of concrete within about 3 mm depth from surface. Experimental results indicate that the long-term durability of RPC is significantly improved with the hydration of pozzolanic materials, which produces a very dense structure and thus exhibiting improved durability.

並列關鍵字

Reactive Powder Concrete ； Durability ； Engineering barrier

參考文獻

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