Characterization of the absolute volume change of cement pastes in early-age hydration process based on helium pycnometry
Characterization of the absolute volume change of cement pastes in early-age hydration process based on helium pycnometry
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DOI：
10.1016/j.conbuildmat.2017.03.108
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发表时间：
2017-07-01
影响因子：
7.4
通讯作者：
Ji, Yanliang
中科院分区：
文献类型：
--
作者：
Yang, Xu;Sun, Zhenping;Ji, Yanliang
基于氦体积测量检测技术，提出了一种表征水泥浆体早期水化过程绝对体积变化的新方法。该方法可以准确、连续地监测水泥浆体的绝对体积变化，即使在纳米尺度下也不包括所有空孔隙空间。采用化学收缩试验（基于ASTM C 1608）、等温量热试验、x射线衍射（XRD）分析等传统方法进行对比分析。发现化学收缩试验所得数据不连续、不准确，等温量热试验所得数据模糊、不专一，XRD分析所得数据不连续、不专一。与传统方法相比，氦比测法捕获的结果连续、准确、特异，可描述水化过程，尤其是绝对体积变化的变化细节。但与此同时，氦比测法与传统方法有很好的一致性，两者的趋势基本一致。根据水泥浆体早期水化过程的绝对体积变化和热流变化趋势，将水泥浆体早期水化过程的绝对体积变化分为溶解期、诱导期、快速反应期和稳定期四个阶段。(C) 2017 Elsevier Ltd.版权所有。
Based on detection technology of helium pycnometry, this study developed a novel approach for characterizing the absolute volume change of cement pastes in early-age hydration process. This method gives an accurate and continuous surveillance on the absolute volume change of cement pastes excluding all the empty pore space even below nm-scale. Traditional methods, such as chemical shrinkage test (based on ASTM C 1608), isothermal calorimetry test and X-ray diffraction (XRD) analysis, are also adopted for comparison and analyzation. It was found that the data obtained by chemical shrinkage test is discontinuous and inaccurate, the data gotten by isothermal calorimetry test is vague and unspecific, and the data gained by XRD analysis is discontinuous and unspecific. Compared with the traditional methods, the results captured by helium pycnometry are continuous, accurate and specific for describing the hydration process, especially the changing details of the absolute volume change. But at the same time, helium pycnometry has a good correspondence with the traditional methods, whose trends are almost the same. Based on the trends of the absolute volume change and heat flow, the absolute volume change of cement pastes in early-age hydration process was then divided into four periods (dissolution period, induction period, fast reaction period and stable period). (C) 2017 Elsevier Ltd. All rights reserved.