| 摘要: |
| 采用磁力搅拌+超声波分散+聚羧酸高效减水剂方法来提高纳米TiO2（NT）在水泥净浆中的分散性与稳定性，研究了不同掺量NT对水泥净浆力学性能的影响，通过水化热、热重-差示扫描量热（TG-DSC）分析、压汞（MIP）等测试方法，研究NT对水泥水化性能的影响机理.结果表明：采取磁力搅拌20 min、超声波分散15 min、再磁力搅拌15 min，并辅以聚羧酸高效减水剂，可制得分散稳定的NT悬浮液；当NT掺量为2.0%时，水泥净浆的抗压强度最大，且在相同掺量下，使用悬浮液法制备的水泥净浆力学性能高于干混法；NT可显著缩短水泥水化的诱导期，提高水泥早期水化放热速率，改变CH的结晶度及取向，并优化硬化水泥净浆内部的孔隙结构，提高其力学性能. |
| 关键词: 纳米TiO2 分散性 力学性能 水化机理 孔径分布 |
| DOI：10.3969/j.issn.1007-9629.2022.08.011 |
| 分类号:TU528 |
| 基金项目:湖南省教育厅重点项目（19A164，19K033）；国家级大学生创新创业训练项目（S202010534006）；清远市科技计划项目（2018A021）；湖南省交通运输厅科技进步与创新计划项目（202114） |
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| Effect of Nano-TiO2 Dispersibility on the Mechanics， Hydration Degree and Microscopic Properties of Cement Paste |
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ZHU Shifeng1,2, WANG Gongxun1,2, DENG Jing1, LIU Fucai3, XIAO Min3
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1.School of Civil Engineering， Hunan University of Science and Technology， Xiangtan 411201， China;2.Hunan Engineering Research Center for Intelligently Prefabricated Passive House， Xiangtan 411201， China;3.Guangdong Gaiteqi New Materials Technology Co.， Ltd.， Qingyuan 511600， China
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| Abstract: |
| The method of magnetic stirring combined with ultrasonic dispersion and addition of polycarboxylic acid water reducer was used to improve the dispersion and stability of nano-TiO2（NT） in cement paste， and the effect of different content of NT on the mechanical properties of cement paste was studied. Measurement of hydration heat， thermogravimetric-differential scanning calorimetry （TG-DSC） and mercury intrusion method（MIP） were used to study the influence mechanism of NT on cement hydration performance. The results show that dispersion and stable NT suspension can be prepared by adopting magnetic stirring for 20 minutes， ultrasonic dispersion for 15 minutes， and magnetic stirring for 15 minutes， supplemented with polycarboxylic acid water reducer. When the content of NT is 2%， the compressive strength of cement paste is the largest， and under the condition of the same NT content， the mechanical properties of cement paste prepared with the suspension are higher than that of the dry mixing method. NT can significantly shorten the induction period of cement hydration， increase the rate of early cement hydration heat release， change the crystallinity and orientation of CH， optimize the internal pore structure of the hardened cement paste， and improve its mechanical properties. |
| Key words: nano TiO2 dispersion mechanical property hydration mechanism pore size distribution |
