| 引用本文: | 梁华明,朱文彬,郭鑫志,卢艺菲,周春圣.掺硫铝酸钙类膨胀剂白水泥净浆干燥收缩与水分损失关联[J].哈尔滨工业大学学报,2025,57(1):140.DOI:10.11918/202407009 |
| LIANG Huaming,ZHU Wenbin,GUO Xinzhi,LU Yifei,ZHOU Chunsheng.Relationship between drying shrinkage and water loss of white cement paste containing calcium sulfoaluminate expansive agent[J].Journal of Harbin Institute of Technology,2025,57(1):140.DOI:10.11918/202407009 |
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| 摘要: |
| 为精确解析干燥条件下掺硫铝酸钙类膨胀剂水泥基材料的收缩行为,深入揭示低相对湿度条件下硫铝酸钙类膨胀剂补偿收缩效果下降的机制,利用低场磁共振弛豫技术,结合X射线衍射、质量与长度测试,在不同相对湿度下对掺与不掺硫铝酸钙类膨胀剂白水泥净浆的干燥收缩历程进行10个月的长期监测,从含水量及水分状态角度,定量描述白水泥净浆干燥失水和收缩的演变规律,阐明硫铝酸钙类膨胀剂导致干燥收缩落差增大的作用机制。结果表明:在相对湿度为75%、43%、11%的环境中干燥,白水泥净浆失水量和干燥收缩均持续增大直至稳定,3类环境中各试件干燥收缩与相对失水量间的关系基本保持一致；随干燥时间延长,单位失水量导致的干燥收缩先降低后升高,干燥进程中净浆内部各级孔隙失水规律不同,且各湿度条件下的干燥收缩机制存在差异；掺入硫铝酸钙类膨胀剂后,C-S-H凝胶纳米孔结构会发生一定粗化,干燥时易损失更多可蒸发水,且膨胀剂水化生成的钙矾石还会损失2~5个结晶水,二者共同导致净浆水分损失与干燥收缩增大；在低湿度环境中应用硫铝酸钙类膨胀剂时,需注意这两个因素导致收缩落差增大的影响。 |
| 关键词: 白水泥 硫铝酸钙类膨胀剂 干燥收缩 水分损失 低场磁共振 |
| DOI：10.11918/202407009 |
| 分类号:TU528.01 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(52078172)；中国高校基本科研业务费专项资金(HIT.OCEF.2021022) |
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| Relationship between drying shrinkage and water loss of white cement paste containing calcium sulfoaluminate expansive agent |
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LIANG Huaming1,ZHU Wenbin2,GUO Xinzhi1,LU Yifei1,ZHOU Chunsheng1
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(1.School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China; 2.Central-Southern Safety and Environment Technology Institute Co. Ltd., Wuhan 430071, China)
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| Abstract: |
| To accurately analyze the shrinkage behavior and mechanism of cement-based materials containing calcium sulfoaluminate expansive agent under drying conditions and reveal the mechanism of the decline in the compensatory shrinkage effect of calcium sulfoaluminate expansive agent under low relative humidity conditions, the non-destructive low-field nuclear magnetic resonance relaxation technique was adopted to monitor the development of drying shrinkage of white cement paste with and without calcium sulfoaluminate expansive agent at different levels of relative humidity for 10 months, as well as X-ray diffraction test, mass and length monitoring for specimens. From the perspective of both water content and its state, the evolution of drying shrinkage of white cement paste was quantitatively described, the relationship between drying shrinkage and relative water loss was established, and the mechanism of CSA increasing drying shrinkage was elucidated. Results indicate that, dry in environments with 75%, 43% and 11% RH, water loss and drying shrinkage of white cement paste continually increase until stabilization. The relationship between drying shrinkage and relative water loss of specimens in the three types of environments remained almost the same.With the extension of drying time, the drying shrinkage caused by unit water loss initially decreases and then increases. This change can be explained by the difference of water loss in pore at all levels in cement paste during the drying process, and the non-identical mechanism of drying shrinkage under different humidity conditions. When calcium sulfoaluminate expansive agent is mixed into cement-based materials, C-S-H gel nanopore structure will be coarsened to some extent, easy to lose more evaporable water when drying, and ettringite generated by the hydration of the expansion agent will also lose 2 to 5 water of crystallization, both of which together lead to the net slurry moisture loss and drying contraction are increased. In the application of calcium sulfoaluminate expansive agent in the low humidity environment, it needs to pay attention to these two factors leading to the contraction of the impact of increased fall. |
| Key words: white cement calcium sulfoaluminate expansive agent drying shrinkage water loss low-field nuclear magnetic resonance |
