纤维素醚对早期钙矾石形貌影响的对比研究

纤维素醚对早期钙矾石形貌影响的对比研究

钱匡亮¹，彭  宇¹，赵国荣²，王培铭²

(1.浙江大学建筑工程学院，浙江 杭州 310058；2. 同济大学材料科学与工程学院，上海 201804)

摘  要  通过扫描电镜对比研究了羟乙基甲基纤维素醚和甲基纤维素醚对早期普通水泥浆体内钙矾石形貌特征的影响并分析了两者的影响机制。结果表明：羟乙基甲基纤维素醚改性水泥浆体内的钙矾石晶体的长径比小于普通水泥浆体内的钙矾石晶体，并呈现出短棒状的形貌特征；甲基纤维素醚改性水泥浆体内的钙矾石晶体长径比大大于普通水泥浆体内的钙矾石晶体，并呈现出针棒状的形貌特征；而普通水泥浆体内的钙矾石晶体的长径比介于这两者之间。通过上述试验研究进一步明确了两种纤维素醚分子量的不同是对钙矾石形貌产生影响的最主要因素。

关键词  钙矾石；长径比；甲基纤维素醚；羟乙基甲基纤维素醚；形貌

中图分类号：TU528；TU502；TG115.21⁺5.3    文献标识码：A    doi:10.3969/j.issn.1000-6281.2020.03.007

Comparison on morphology of ettringite transformedby different cellulose ethers at early ages

QIAN Kuang-liang¹，PENG Yu¹，ZHAO Guo-rong²，WANG Pei-ming²

(1. College of Civil Engineering and Architecture, Zhejiang University, Hangzhou Zhejiang 310058；2. School of Materials Science and Engineering, Tongji University, Shanghai 201804, China)

Abstract  Morphology of ettringite (AFt) in hardened cement pastes modified by two cellulose ethers at early ages (1 day) has been comparatively investigated by SEM and mechanism of this transformation has been hypothesized based on their morphology. Results showed that morphology of AFt in hardened cement pastes modified by HEMC was at the lowest Length-Diameter Ratio(L/D ratio), which presented the “shot-stick” characteristic. Morphology of AFt in hardened cement pastes modified by MC was at the highest L/D ratio, which presented the “needle-like” characteristic. Morphology of AFt in blank cement pastes was at the middle L/D ratio, which presented the regular characteristic as usual. The different effects of the two cellulose ethers on the morphology of AFt are essentially due to their different molecular weights.

Keywords  ettringite；length-diameter ratio；methyl cellulose；hydroxyethyl methyl cellulose；morphology

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