水中自充填混凝土礦物摻料組合之研究

Abstract

本研究以提高混凝土耐久性、體積穩定性且擁有自充填、水中不析離的特性為試驗目標，使用不同種類之水中不析離劑(Underwater Anti-segregation Admixture，UWASA-趙教授研究室所研發之水中不析離劑系列)及在礦物摻料(P1、P2、P3)上做不同比例的調整，設計出數種適用於水中結構物之自充填混凝土配比，除了測試其工作性符合SCC規定標準外，在混凝土硬固後，放置於不同相對濕度(RH40%、RH80%、RH100%)的環境中，測試其力學性質、體積穩定性及耐久性，以確保混凝土之品質。將設計的水中自充填混凝土配比與一般SCC做比較，比較內容包括抗壓強度、體積穩定性、混凝土耐久性等，其中體積穩定性做乾燥收縮，分別比較鋼筋量對乾縮的影響，耐久性測試為快速氯離子滲透試驗(RCPT)與電阻率試驗。由試驗結果得知，添加與以往不同分子量之水中不析離劑(UWASA-B )，在相同的配比上，其水中不分散能力(通過L型流度測試之pH值與濁度值)能保持過去之品質，電阻率方面有相對較高，但抗壓強度則較為低，而RCPT由於有較多因素的干擾，所以不能明確說明是否有較好；對於體積穩定性試驗來看，可看出加入鋼筋的混凝土的確有抑制乾縮之效果，且鋼筋量越多，抑制的效果越好。

This study is to improve the durability, volume stability of underwater self-compacting concrete with various underwater anti-segregation admixtures developed by Dr. Wen-Chen Jau. Pozzolans are used with different percentage for comparison. The workability, passing ability, slump-flow, and V-funnel tests were performed to determine the self-compacting ability of the concrete. After the concrete hardened, the specimens were kept in different RH(40, 80%, and 100%) to determine the mechanical properties, volume stabilities, and durability. It is found that different anti-segregation admixtures exhibit different performs in terms of anti-washout, RCPT, and electrical resistance. In addition, it is also found that steel rebar can effective restrain the shrinkage, and better for higher steel ratio.