Humidity Driven Transition from Insulator to Ionic Conductor in Portland Cement
Humidity Driven Transition from Insulator to Ionic Conductor in Portland Cement
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DOI：
10.3390/ma12223701
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发表时间：
2019-11
期刊：
影响因子：
3.4
通讯作者：
M. Nagao;Kazuyo Kobayashi;T. Hori;Yaorong Li;T. Hibino
中科院分区：
文献类型：
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作者：
M. Nagao;Kazuyo Kobayashi;T. Hori;Yaorong Li;T. Hibino
这项工作的目的是评估老化期为5-25天的无水水泥颗粒和水化水泥浆体的离子导电性。当水泥样品在50-100 °C范围内加湿（相对湿度= 100%）时，无论水化程度如何，其体积电导率均为10−3-10−2 S cm−1，而界面电导率在10−7-10−3 S cm−1范围内变化，这取决于样品的结构缺陷或传导途径。体电导率和界面电导率在100 °C下都增加到0.01 S cm-1或更高，尽管样品需要预先用水雾润湿。样品中的主要电荷载体被确定为氢氧根离子，并且总离子迁移数约为1。将样品暴露于二氧化碳和水蒸气的混合物中会导致体电导率和界面电导率的降低;然而，通过用酸处理，体电导率恢复到初始值。
This work aims to assess ionic conduction in anhydrous cement particles and hydrated cement pastes with aging periods of 5–25 days. When a cement sample was humidified (relative humidity = 100%) over the range of 50–100 °C, it exhibited bulk conductivities of 10−3–10−2 S cm−1, regardless of the hydration level, whereas the interfacial conductivities varied in the range of 10−7–10−3 S cm−1, depending on the structural defects or conduction pathways of the sample. Both the bulk and interfacial conductivities were increased to 0.01 S cm−1 or higher at 100 °C, although the sample required previous moistening with water mist. The major charge carrier in the sample was determined to be hydroxide ions, and the total ion transport number was approximately 1. Exposing the sample to a mixture of carbon dioxide and water vapor caused a decrease in the bulk and interfacial conductivities; however, the bulk conductivity was returned to the initial value by treatment with an acid.