高吸水树脂基内养护水分在水泥浆体中的释放及水化规律

Release and Hydration Rules of Internal Curing Water for Super Absorbent Polymer in Cement Paste

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关键词:

高吸水树脂;内养护;核磁共振;水化

Key words:

Super absorbent polymer; Internal curing; NMR; Hydration

刊期:

2017年第7期

DOI:

文章编号:

1000-4637(2017)07-01-05

基金项目:

国家自然基金项目(51578545);中国铁道科学研究院基金(2016YJ048)

作者:

李享涛1,2

单位:

1.中国铁道科学研究院 铁道建筑研究所,北京 100081;2.高速铁路轨道技术 国家重点实验室,北京 100081)

摘要

摘   要:以高吸水树脂(SAP)为内养护水分蓄存载体,采用核磁共振法研究了内养护水分在水泥浆体中的释放规律,探索了其对水泥浆体毛细负压的影响以及参与水化的特征。结果表明,高吸水树脂基内养护水泥浆体的0.1~6ms弛豫峰和32.7~200.9ms、231.0~1629.7ms弛豫峰分别由毛细水、内养护水产生;内养护水分的释放始于水泥浆体水化加速期,内养护时间随蓄水SAP掺量的增加而延长;释放出的内养护水分降低了水泥浆体的毛细负压,同时也促进了水泥浆体的水化;SAP仅控制的是内养护水分的释放速率,内养护水泥浆体与直接增加相同额外水量的浆体后期水化程度相当。

Abstract: Based on super absorbent polymer served as carrier of internal curing water, release of internal curing water in cement paste was studied with NMR method, and its effect on capillary pressure of cement paste as well as characteristics of participation in hydration were analyzed. It was indicated from the results that 0.1 ~ 6ms relaxation peak was induced by capillary water, 32.7~200.9ms and 231.0~1629.7ms relaxation peak were induced by internal curing water in internal curing paste; the release of internal curing water started in the beginning of hydration acceleration period, and internal curing duration increased with the increase of dosage of SAP. The internal curing water released would not only reduce the capillary pressure, but also promote the hydration of cement paste. As SAP only controlled release rate of internal curing water, late hydration degree of internal curing paste was the same as that of the paste with adding equal additional water directly.

结论

(1)核磁共振法能便捷测试水泥浆体中不同状态水的含量变化,对于高吸水树脂基内养护水泥浆体,0.1~6ms弛豫峰是由毛细水产生的,32.7~200.9ms和231.0~1629.7ms弛豫峰是由SAP吸蓄的内养护水产生的。
(2)水泥浆体进入水化加速期时,内养护水分开始释放,内养护时间随蓄水SAP掺量的增加而延长,掺0.3%SAP的水泥浆体内养护时间可达12d。
(3)随着内养护水分的释放,一方面能降低水泥浆体的毛细负压,另一方面又能促进水泥浆体的水化。
(4)SAP仅控制内养护水分的释放速率,内养护水泥浆体与直接增加相同额外水量的浆体后期水化程度相当。

参考文献

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引用本文

李享涛.高吸水树脂基内养护水分在水泥浆体中的释放及水化规律[J].混凝土与水泥制品,2017(7):1-5.

LI X T.Release and Hydration Rules of Internal Curing Water for Super Absorbent Polymer in Cement Paste[J].China Concrete and Cement Products,2017(7):1-5.


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