Characterization of air-void systems in 3D printed cementitious materials using optical image scanning and X-ray computed tomography
Characterization of air-void systems in 3D printed cementitious materials using optical image scanning and X-ray computed tomography
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DOI：
10.1016/j.matchar.2021.110948
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发表时间：
2021-02-12
影响因子：
4.7
通讯作者：
Schlangen, Erik
中科院分区：
文献类型：
--
作者：
Chen, Yu;Copuroglu, Oguzhan;Schlangen, Erik
对于许多3D打印的胶凝材料，气孔可能在层间结合强度中起主导作用。然而，到目前为止，人们对揭示3D打印胶凝材料中的气孔特性的关注还太少。因此，为了填补这一空白，本研究试图通过不同的图像采集和分析技术来系统地表征3D打印水泥基材料的典型气孔系统。两种可打印的石灰石和煅烧粘土基混合物被用来制备打印样品。通过光学图像扫描和X射线计算机断层扫描获得显微图像。然后，确定了印刷胶凝材料中的气孔指标，即含量、分布、大小和形状。结果表明，大部分直径在10-1000微米之间的气孔均匀地分布在印刷样品的层状区。较大的气孔(1000-6000微米)主要封闭在印刷细丝(界面区)之间，导致局部孔隙率相对较高。此外，大多数气泡呈现不规则和拉长的形状，这可能归因于3D打印中的挤出和分层制造工艺。最后，对光学图像扫描与X射线层析成像进行了比较。
For many 3D printed cementitious materials, air voids may play a dominant role in the interlayer bond strength. However, to date, far too little attention has been paid to reveal the air void characteristics in 3D printed cementitious materials. Therefore, to fill this gap, this study attempts to provide an example of systematically characterizing the typical air void system of 3D printed cementitious materials via different image acquisition and analysis techniques. Two printable limestone and calcined clay-based mixtures were employed to prepare the printed samples. The micrographs were acquired by using optical image scanning and X-ray computed tomography. Afterwards, air void metrics in printed cementitious materials were determined, i.e., content, distribution, size, and shape. The results revealed that most of the air voids with the diameter in the range of 10-1000 mu m were distributed evenly in the layer region of printed samples. Large air voids (1000-6000 mu m) were enclosed mainly between the printed filaments (interface region), which resulted in the relatively higher local porosity than that of layer region. Additionally, the majority of air voids displayed irregular and elongated shapes, which could be attributed to the extrusion and layer-wise manufacturing processes in 3D printing. Finally, a comparison between optical image scanning and X-ray computed tomography was given.