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氯离子结合陶砂及其性能研究
作者：严建华1，张欢1，冀欣鑫1，郝挺宇2，唐鑫科1
（1.北京工业大学，北京 100124；2.中冶建筑研究总院有限公司，北京 100088）
摘要：利用赤泥、氢氧化钙等为原料设计了一种核壳结构的烧结陶砂（CSA），该陶砂在水泥浆中使用时，其芯部可固定Cl-，壳部可隔离水泥浆体系，以防止其对芯部Cl-结合性能的影响。分别对芯料、陶砂和掺陶砂砂浆的Cl-结合性能进行了研究，并利用XRD和SEM进行了微观机理分析。结果表明，陶砂的Cl-结合量随龄期的延长逐渐增加，28 d前结合量增长较快，28~90 d结合量增幅减小，趋于平稳；14 d时出现Friedel盐（F盐）的峰，而C3A的峰降低，转化为F盐，28 d时F盐峰值明显。砂浆的Cl-结合率随龄期的延长而增大，同龄期20%CSA砂浆的结合率大于空白样，其中14 d时的结合率相差14.18个百分点；水化初期芯部Cl-浓度较低，优先生成钙钒石，随着水化进行，Cl-浓度增大，与芯部的C3A结合生成F盐。
关键词：氯离子结合；核壳结构；陶砂；F盐；陶砂砂浆
中图分类号：TU528.041 文献标识码：A 文章编号：1001-702X（2022）07-0001-07
Study on the properties of chloride ion bonded ceramic sand
YAN Jianhua1，ZHANG Huan1，JI Xinxin1，HAO Tingyu2，TANG Xinke1
（1.Beijing University of Technology，Beijing 100124，China；
2.MCC Central Research Institute of Building and Construction Co. Ltd.，Beijing 100088，China）
Abstract：In this paper，a core-shell sintered ceramic sand（CSA） was designed using red mud，calcium hydroxide and other raw materials. When the CSA is used in cement paste，the core of the CSA can bind chloride ions，and the shell can isolate the cement paste system to prevent its influence on the chloride binding properties of the core. The chloride binding properties of core material，CSA and mortar mixed with CSA were studied，and the microstructure mechanism was studied by XRD and SEM. The results showed that the chloride binding amount of the CSA increases gradually with the growth of age. Before 28 d，the binding amount increases rapidly，and from 28 d to 90 d，the increasing range of the binding amount decreases and tends to be stable. At 14 d，Friedel's salt peak appeared，C3A peak decreased and converted to Friedel's salt. At 28 d，Friedel's salt peak is evident. The chloride binding rate of mortar increases gradually with curing ages. The binding rate of 20%CSA mortar at the same age is greater than that of blank sample，and the difference of binding rate at 14 d is 14.18%. At the early stage of hydration，the concentration of chloride in the core is low，and ettringite is preferentially generated. As hydration progresses，the concentration of Cl- increases and combines with C3A in the core to form Friedel's salt.
Key words：chloride binding，core-shell structure，ceramic sand，Friedel's salt，ceramic sand mortar