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Active rheology control of cementitious materials: New insights from magneto-responsive aggregates
Cement and Concrete Research ( IF 10.9 ) Pub Date : 2024-12-31 , DOI: 10.1016/j.cemconres.2024.107707
Yiyuan Zhang, Yaxin Tao, Jose R.A. Godinho, Kim Van Tittelboom, Karel Lesage, Geert De Schutter

This study aims to achieve active rheology control of cementitious materials from the new view of magneto-responsive aggregates. It provides a sound experimental validation, qualitative analysis and quantitative characterization of magnetorheological response and mechanism of cementitious materials containing responsive aggregates under a nozzle/pipe-like (inline) external magnetic field. Specially, the aggregate shape indicators, rheological responses and micro-/meso- structures are described. The physical, chemical and geometrical features of aggregates were determined by X-ray diffraction analysis (XRD), vibrating sample magnetometer (VSM), loose packing fraction, optical microscopy and X-ray computed tomography (CT). The slow penetration test and vane test were conducted to measure the structural build-up of fresh samples with and without an inline magnetic intervention by using a rheometer-based customized test setup. The spatial distribution of magneto-responsive aggregates was determined by employing X-ray CT. The internal skeletal contact properties of magneto-responsive aggregates including cluster orientation, cluster aspect ratio, cluster elongation, contact point number, contact length and contact area were characterized quantitatively from the 3D image. A newly developed magneto-responsive cement mortar which can adjust rheological properties in time and on demand was achieved. The alignments of magneto-responsive aggregates along the magnetic induction lines were visualized. The orientation of magneto-responsive aggregate clusters showed concentrated distribution. With the decrease of the cement-to-aggregate ratio and increase in the size of magneto-responsive aggregates, the field-induced yield stress and torque increased significantly, which also influenced the contact properties of magneto-responsive aggregates. These results are beneficial for the application of active rheology control of magneto-responsive cementitious materials.

中文翻译:


胶凝材料的主动流变控制:来自磁响应骨料的新见解



本研究旨在从磁响应骨料的新观点实现胶凝材料的主动流变控制。它为在喷嘴/管道状(内联)外部磁场下含有响应聚集体的胶凝材料的磁流变响应和机理提供了可靠的实验验证、定性分析和定量表征。特别地,描述了聚集体形状指标、流变响应和微/中尺度结构。通过 X 射线衍射分析 (XRD)、振动样品磁力计 (VSM)、松散堆积分数、光学显微镜和 X 射线计算机断层扫描 (CT) 确定聚集体的物理、化学和几何特征。使用基于流变仪的定制测试装置,进行慢速渗透测试和叶片测试,以测量有和没有在线磁干预的新鲜样品的结构堆积。磁响应聚集体的空间分布是通过 X 射线 CT 确定的。从 3D 图像中定量表征了磁响应聚集体的内部骨骼接触特性,包括团簇方向、团簇纵横比、团簇伸长率、接触点数、接触长度和接触面积。实现了一种新开发的磁响应水泥砂浆,它可以及时按需调整流变特性。磁响应聚集体沿磁感应线的排列被可视化。磁响应聚集团簇的取向呈集中分布。 随着水泥与骨料比的降低和磁响应骨料尺寸的增加,场感应屈服应力和扭矩显著增加,这也影响了磁响应骨料的接触性能。这些结果有利于磁响应胶凝材料的主动流变控制应用。
更新日期:2024-12-31
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