以燃煤飛灰製成無機聚合樹脂應用於混凝土補強之可行性研究

A Feasibility Study on CFRP Confined Concrete Using Coal Fly Ash Based Geopolymer Resin

張文華(Wen-Hua Chang)

指導教授 ： 鄭大偉

國立臺北科技大學/工程學院/材料及資源工程系所/碩士(2006年)

摘要

電力事業燃燒煤炭發電，而煤燃燒後所殘留之固態殘留物即為煤灰。煤灰可分為底灰及飛灰二大類，其中飛灰產量約為底灰的四倍，因此需更積極尋求飛灰多方面之用途，以提升飛灰之利用量。本研究用燃煤飛灰及變高嶺石為初始原料，以矽酸鈉溶液及NaOH溶液混合配製成不同莫耳比(SiO2/Na2O)之鹼性溶液，將其製成無機聚合樹脂，作為混凝土補強之黏著劑。
混凝土補強一般是以碳纖維包覆混凝土，並使用環氧樹脂為包覆之黏著劑。當遭受火害時混凝土內部產生大量水氣，因環氧樹脂具不透氣性，水氣無法順利排除，導致混凝土內部孔隙壓力遽增進而產生爆裂。而無機聚合樹脂硬化後為一種類似沸石之多孔架狀結構，透氣性良好，且具有製作簡單、耐高溫、抗酸鹼腐蝕等優點。本研究以燃煤飛灰製成無機聚合樹脂取代傳統包覆用之環氧樹脂並評估其可行性。此外，將碳纖維作表面處理，更進一步提升無機聚合樹脂與碳纖維及混凝土界面間之黏結性。
研究結果顯示，SiO2/Na2O莫耳比為0.75所製成之無機聚合材料具有較佳之機械強度及耐火特性。將其應用於混凝土圍束補強之黏結劑，圍束1層約可增強抗壓強度1.5倍；圍束2層約可增強2倍。其中將圍束1層之混凝土定載85 %之破壞荷重後升溫以量測其黏結失效溫度約為516 ℃(而環氧樹脂之失效溫度僅為100 ~ 300℃)。此外藉由碳纖維表面處理以增加碳纖維與無機聚合樹脂之黏結強度，最佳處理條件為碳纖維浸泡於0.5 N之硫酸溶液中5分鐘，其層間剪力強度可由8.5 kgf/cm2增加至13.4 kgf/cm2。因此以燃煤飛灰製成之無機聚合樹脂，應用於混凝土補強之黏結劑具有相當之潛力。

關鍵字

燃煤飛灰 ； 無機聚合樹脂 ； 碳纖維表面處理 ； 層間剪力強度

並列摘要

There are two types of coal ashes, i.e. bottom ash and fly ash. Generally, the amount of coal fly ash is four times of coal bottom ash, therefore, it needs more techniques to reutilize. This research work utilized coal fly ash, metakaolinite and alkali solution with different SiO2/Na2O molar ratio as raw materials in order to form geopolymer resin as the binder for CFRP confined concrete.
The experimental results show that the geopolymer at the SiO2/Na2O molar ratio of 0.75 can be obtained the best compressive strength and the fire resistance characteristics. Using this molar ratio as the binder of CFRP confined concrete, the compressive strength can be increased 150% for covering one layer CFRP and raised 200% for covering two layers CFRP. Concrete cylinders with one layer CFRP at its 85% strength loading, the effect of confinement lost completely when the temperature reached 516℃ (100~300℃ for epoxy as the bonding material). On the other hand, carbon fiber surface treatment also increased adhesive strength. The best treatment condition was immersing carbon fiber at 0.5N H2SO4 solution for 5 min. and the Interlaminar shear strength of carbon fiber layer can be increased 157%. Therefore, using coal fly ash to make geopolymer resin as CFRP confined concrete binder has great potential for engineering and construction applications.

並列關鍵字

Coal fly ash ； Geopolymer resin ； Carbon Fiber Surface Treatment ； Interlaminar Shear Strength ； CFRP Confined Concrete

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