| 摘要: | 加速鋰離子傳輸技術(ALMT)抑制混凝土ASR問題的策略，是利用電場趨動力，在移除會誘發混凝土ASR問題的Na+及K+同時，送入可以抑制ASR問題的Li+。本研究先探討電場條件、試體材料配比及ASR劣化程度差異等，對ALMT試驗的陽離子傳輸行為影響，從中尋找評估陽離子傳輸參數的指標，並提出需要獲得的陽離子傳輸參數項目及分析方法，建立陽離子傳輸參數與傳輸指標之間的關係。結果顯示，陰極槽內的陽離子濃度－時間曲線，依ASR劣化程度區分為二種類型，而二者相同處，是均包含Na+及K+穩定移出及移出完成二個傳輸階段，而Li+均可區分為非穩態、過渡及穩態三個傳輸階段。二者相異處，是ASR劣化程度較高者，Li+達到穩態階段所需時間較短。藉分析陰極槽內的陽離子濃度－時間曲線，可以獲得Na+及K+移出完成時間、移出量及單位時間移出量、Li+穿過試體時間、非穩態傳輸係數、穩態流量及穩態傳輸係數等參數，縱使試驗條件改變，上述參數與適合作為傳輸指標的電流密度之間，都可以建立適當的趨勢關係。增加電場強度、縮短試體長度、增加粒料體積比例、減少水泥含鹼量、增加水灰比及增加試體ASR劣化程度，均可增加Na+及K+的單位時間移出量，縮短Na+及K+移出完成時間，縮短Li+穿過試體時間，增加Li+穩態流量及傳輸係數。 由傳輸進入陰極槽內的陽離子累積帶電量與施加電量曲線，發現可以Na+移出完成時的累積施加電量為界，區分為Na+及K+穩定移出及Li+穩態傳輸二個線性段，二者斜率(TA及TLi)分別代表施加電量用於陽離子傳輸的比例，可以發現TA均大於TLi。增加電場強度、縮短試體長度、增加粒料體積比例、增加試體水灰比、試體ASR劣化程度增加等，均會提高TA及TLi值。增加系統含鹼量則會提高TA值，但會降低TLi值。 最後，本研究以如何獲得欲抑制ASR問題混凝土在電場作用下的Li+、Na+及K+傳輸參數，所需要進行的試驗程序、觀察項目、可套用的理論分析式，及傳輸參數與電流密度關係式特性等，建構一個容易遵循的標準化分析程序，可以提供工程實務運用單維電場抑制混凝土ASR時，作為獲得設計參數的方法。 The Accelerated Migration Technique (ALMT) uses the driving force of electrical field to remove Na+ and K+ from concrete, and simultaneously drive Li+ into concrete to inhibit alkali-silica reaction (ASR). This study discusses the behavior of cations under ALMT influencing by the electrical field conditions, the proportion of concrete mixtures, and the ASR deterioration degree, firstly, to seek the evaluated index of the migration parameters of cations, propose the required items of the parameter and the analysis method, then establish the relationship between the migration parameters and the index. The result shows that the curves between the cation concentrations in catholyte and time, can be divided into two types according to the ASR deterioration degree of concrete. The two types both contain the Na+ and K+ stable migration and the completed migration stages, and the Li+ non-steady state, transition, and steady state. For concrete with higher ASR deterioration degree, the needed time to reach the Li+ steady state is shorter. From the curve between the cation concentrations in catholyte and time, the required migration parameters can be obtained, including the removal time, removal amount and unit time removal amount of the Na+ and K+, and the passing time, the non-steady state migration coefficient, the steady state flux and migration coefficient of the Li+. Though the test condition may change, the above parameters can still establish suitable relationship with the applied current density. Increasing the electrical field, a/c ratio, w/c ratio and the ASR deterioration degree, and reducing the length of sample and alkali amount of cement, can increase the unit time removal amount and reduce the removal time of the Na+ and K+, reduce passing time and increase the steady flux and migration coefficient of the Li+. The relationship between the cations accumulated charge migrating into the catholyte and the applied charge shows that the curve include the alkalis removed and the Li+ impregnated linear regions (TA and TLi). The accumulated charge until Na+ is removed completely is found just in the boundary between the two regions. The linear slope of the alkalis removed region is greater. While increasing the applied voltage, a/c ratio, w/c ratio, and the ASR deterioration degree, and decreasing the length of sample, can increase the proportion of the applied charge being used for cation migration. But increasing the system alkali amount can increase TA and reduce TLi. Finally, this research proposes the standardized procedure to obtained the migration parameters of the Li+, Na+, and K+, including the needed testing steps, the observing items, may applied theory, and the relationship between the migration parameters and the current density. |
