不同养护温度下氯化钠对铝酸盐水泥水化的影响
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摘要
采用X射线衍射仪、扫描电镜、压汞仪、量热仪分析了5℃、20℃和40℃下NaCl对铝酸盐水泥水化的影响。结果表明,当NaCl掺量较低时,会加快铝酸盐水泥的早期水化速率,而掺量较高时则会延缓早期水化。此外,NaCl对铝酸盐水泥水化产物的影响还高度依赖于养护温度。5℃和20℃下,NaCl的掺入使得早期CAH10的生成量大幅增加,水泥的孔结构优化、强度明显提升。而40℃下,NaCl加速了介稳的水化铝酸钙(CAH_(10)、C_2AH_8)向C_3AH_6的转变,促使硬化水泥石中有害孔的比例大幅增加、强度降低。虽所涉温度下氯离子结合量均随NaCl掺量的升高而增大,但增长的趋势逐渐变缓;且5℃和20℃下氯离子结合量随着龄期的延长而增大,而40℃下氯离子结合量随龄期延长不断下降。
Effects of NaCl on the hydration of calcium aluminate cement( CAC) at 5 ℃,20 ℃ and 40 ℃ were analyzed by X-ray diffraction,scanning electron microscopy,mercury intrusion porosimetry and calorimetry. Results show that lower amount of NaCl accelerates the early hydration of CAC,while excessive NaCl delays the early hydration of CAC. Effects of NaCl on the hydration products of CAC are highly dependent on the curing temperature. At 5 ℃ and 20 ℃,the incorporation of NaCl greatly contributes to the formation of CAH10,thus the pore structure is optimized and compressive strength is enhanced significantly. At 40 ℃,the addition of NaCl accelerates the transition from metastable hydration products( CAH_(10),C_2 AH_8) to C_3 AH_6,leading to a significant increasing in the amounts of harmful pores in hardened cement paste and an obvious decrease in strength. Although the amount of bounded chloride ions increases with the increase of NaCl content,the trend of increasing gradually slows down. With the proceeding of hydration,the amount of bounded chloride ion increases at 5 ℃ and 20 ℃,while it decreases with age at 40 ℃.
Effects of NaCl on the hydration of calcium aluminate cement( CAC) at 5 ℃,20 ℃ and 40 ℃ were analyzed by X-ray diffraction,scanning electron microscopy,mercury intrusion porosimetry and calorimetry. Results show that lower amount of NaCl accelerates the early hydration of CAC,while excessive NaCl delays the early hydration of CAC. Effects of NaCl on the hydration products of CAC are highly dependent on the curing temperature. At 5 ℃ and 20 ℃,the incorporation of NaCl greatly contributes to the formation of CAH10,thus the pore structure is optimized and compressive strength is enhanced significantly. At 40 ℃,the addition of NaCl accelerates the transition from metastable hydration products( CAH_(10),C_2 AH_8) to C_3 AH_6,leading to a significant increasing in the amounts of harmful pores in hardened cement paste and an obvious decrease in strength. Although the amount of bounded chloride ions increases with the increase of NaCl content,the trend of increasing gradually slows down. With the proceeding of hydration,the amount of bounded chloride ion increases at 5 ℃ and 20 ℃,while it decreases with age at 40 ℃.
引文
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2 Abate C,Scheetz B E. Journal of the American Ceramic Society,2010,78(4),939.
3 Rapin J P,Renaudin G,Elkaim E,et al. Cement and Concrete Research,2002,32(4),513.
4 Sanjuan M A. Corrosion Science,1998,41(2),335.
5 Sanjuan M A. Journal of Material Science,1997,32(23),6207.
6 Ukrainczyk N. Advance in Cement Research,2012,2012(5),249.
7 Goni S,Gaztanaga M T,Sagrera J L,et al. Journal of Material Research,1994,9(6),1533.
8 Barrett P,Bertrandie D. Contributions to Mineralogy and Petrology,2010,169(4),1.
9 Cong X,Kirkpatrick R J. Journal of the American Ceramic Society,2010,76(2),409.
10 Pollmann H. Reviews in Mineralogy and Geochemistry,2012,74,1.
11 Pacewska B,Nowacka M. Journal of Thermal Analysis and Clorimetry,2014,117(2),653.
12 Damidot D,Rettel A,Capmas A. Advances in Cement Research,1996,8,111.
13 Damidot D,Rettel A,Sorrentino D,et al. Advances in Cement Research,1997,9,127.
14 Goni S,Andrade C,Page C L. Cement and Concrete Research,1991,21(4),635.
15 Yang R,Liu B,Wu Z. Cement and Concrete Research,1990,20(3),385.