The influence of the specimen size of ultra-high-performance fibre-reinforced concrete samples on the spatial distribution and orientation of the steel fibres is investigated. Specimens of varying size are produced by using the same protocol. They are imaged by micro-computed tomography to perform a statistical analysis of the spatial arrangement of the fibres. The tensile strength of the specimens is measured by tensile tests on subspecimens of equal size. The results are correlated to geometric characteristics of the fibre systems determined from the image data. Increasing the specimen size results in a larger variability of the local fibre geometry. This effect was most prominent when increasing the height of the specimens.

中文翻译：

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试件尺寸对超高性能纤维混凝土纤维几何形状和抗拉强度的影响

研究了超高性能纤维混凝土试样尺寸对钢纤维空间分布和取向的影响。通过使用相同的协议产生不同大小的样本。它们通过微型计算机断层扫描成像，以对纤维的空间排列进行统计分析。试样的拉伸强度是通过对相同尺寸的子试样进行拉伸试验来测量的。结果与从图像数据确定的纤维系统的几何特征相关。增加试样尺寸会导致局部纤维几何形状的变化更大。当增加试样的高度时，这种效果最为突出。