飛灰水泥漿對乾縮裂縫的自癒能力探討

Self-healing ability of fly ash-cement pastes damaged by a drying condition

何文隆(Vinh-Long Hoang)

指導教授 ： 詹穎雯

國立臺灣大學/工學院/土木工程學研究所/博士(2013年)

https://doi.org/10.6342/NTU.2013.02974

摘要

本研究的目的是調查飛灰水泥(FC)漿在乾燥條件、有效溫度養護，以及不同飛灰摻量的破壞後自癒合效果。此外，目前的工作試圖改善這些水泥漿的自癒能力。
在這項研究中，飛灰取代率為0％、30％、45％和60％的水泥和飛灰水泥漿製備，其中固定水膠比為0.42。為了提高水泥將的自癒能力，Xypex 和石膏添加分別為Xypex 與膠體的比2％和石膏與飛灰的比（G/FA）5％、10％。在50℃烘箱乾燥之後，試體分別存放在25℃飽和石灰水直到180日齡期，在50℃至42日齡期得到癒合的作用。進行抗壓試驗和抗氯離子滲透測試和電子顯微鏡掃描觀測找出試體的自我修復能力。
自我修復FC漿在50℃飽和石灰水養護後，改善固化的強度和降低氯鹽擴展的滲透率。然而，在25℃的養護條件情況下，只顯示能夠減少氯離子滲透。相反地，飛灰摻量在兩個不同的溫度下皆會影響恢復後的抗壓強度。 Xypex顯著地提高了FC漿的抗壓強度自癒效果，跟沒有Xypex 的試體比較提高約20％。在初期含有石膏的試體強度和抗滲性的改善是緩慢的。 在G/FA比值為10％的時候，180日齡期試體的自癒能力表現優良。模擬裂紋表面的微結構與水泥漿基值的微結構區別提出不同環境影響了自我癒合的過程，以及與水泥漿基值的水化作用做比較。這樣的環境可能促進碳化和延遲鈣礬石的形成進而提FC漿的自癒能力。

關鍵字

自我修復 ； 飛灰水泥漿 ； 乾燥條件 ； 溫度 ； Xypex ； 石膏

並列摘要

The purpose of this study is to investigate self-healing behavior of fly ash-cement (FC) pastes damaged by drying condition with a focus on the effect of temperature curing and fly ash content. Furthermore, the present work attempts to improve self-healing capability of these pastes.
In this study, FC pastes with the fly ash replacement ratio of 0%, 30%, 45% and 60 % were prepared, which had a constant water-to-binder ratio of 0.42. To enhance self-healing ability of these pastes, xypex and gypsum were added with 2% of xypex-to-binder ratio and 5%, 10% of gypsum-to-fly ash (G/FA) ratio respectively. After oven-dried at 50oC,specimens were stored in lime-saturated water at 25oC until age of 180 days and at 50oC until age of 42 days to get healing effect. Compressive strength test,rapid chloride permeability test and SEM observation were conducted to determine self-healing ability of thesespecimens.
Self-healing ability of FC pastes cured in 50oC lime-saturated water was performed well by extension of strength improvement and permeability reduction. However, in the case of 25oC condition, the ability only was indicated by decrease of chloride ion penetration. Fly ash content oppositely affects the recovery of compressive strength under the two different temperatures. Xypex significantly improves the healing effect of FC paste in compressive strength, with about 20% higher comparedto pecimens without xypex. The improvement of strength and impermeability of specimens with gypsum is slow during early period. At 10% of G/FA ratio, self-healing capability of the specimen performed well at age of 180 days.The very difference between microstructure on simulated crack surface and in paste matrix suggests the distinct influences of environment on a self-healing process comparing to hydration of paste matrix. Such environment probably promotes carbonation and delays ettringite formation of FC pastes that enhance self-healing capability.

並列關鍵字

Self-healing ； fly ash-cement paste ； drying condition ； temperature ； xypex ； gypsum

參考文獻

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