液固比對鹼激發高流動性混凝土耐久性之影響

Effect of Durability of High Fluidity Alkali-Activated Slag Concrete (HFAASC) with different liquid-solid ratios

本研究是利用水淬爐石粉作為鹼激發材料，以液固比（LS）0.45、0.5、0.55，不同鹼當量（N）5%、6%、7%，製備成高流動性混凝土。進行新拌性質、硬固性質及耐久性質之探討。
結果顯示，鹼激發高流動性混凝土，擁有較佳工作性及較長的凝結時間，但工作性佳，坍流度可達550mm~650mm。在低液固比及高鹼當量有較高抗壓強度。鹼激發高流動性混凝土各配比在初期呈現較佳的激發反應行為，養護齡期28天超音波波速均可達養護齡期56天90%以上。透過快速氯離子滲透所累積的電荷量，觀察到液固比0.55鹼當量5%於養護齡期28天，於試驗時間達1.5小時，達到混凝土氯離子滲透能力之最高滲透等級（4000庫倫），顯示出高液固比及低鹼當量配比設定，耐久性質呈現不佳；以液固比0.45鹼當量5%優於其他配比呈現混凝土氯離子滲透能力之低滲透等級（1000~2000庫倫），擁有較佳的耐久性質。

In this study, ground granulated blast furnace slag (GGBFS) was used to prepare the high- fluidity alkali-activated slag concrete (HFAASC) with different alkali equivalent (N=5, 6 and 7%) and different liquid-solid ratios (L/S=0.45, 0.50 and 0.55), to explore its fresh, mechanical and durability properties. The results show that HFAASC has high workability and longer setting time. Its slump flow obtained was between 550 to 650 mm. Each mix proportion of HFAASC have better initial response behavior at the initial stage. The ultrasonic pulse wave velocity of HFAASC cured at 28 days can reach more than 90% of the one cured at 56 days. As HFAASC with L/S=0.55 and N=5%, the accumulated charge obtained by the rapid penetration of chloride ions can reach to the maximum permeation of chloride ion (4,000 coulombs) in the concrete at 1.5 hours. It also shows that the durability of HFAASC with high liquid-solid ratio and low alkali equivalent ratio is not good. As HFAASC with L/S=0.45 and N=5%, its durability is better than the others with low permeability level of concrete chloride ion permeability (1000 ~ 2000 Coulomb).