This study introduces a double-exponential decay (DED) model to investigate the sampling interval ()-dependent behavior of crack morphology roughness in steel fiber reinforced concrete (SFRC). The root mean square () of the directional derivatives in 3D digital morphology is employed to quantify the roughness and its anisotropic behavior. Surface morphologies of 24 fractured specimens are captured by using a laser scanner and the obtained results are re-meshed based on the Point-Kriging algorithm. The roughness is represented by the ratio of surface area to projected area () and values along different directions at various s (4–3000 μm). The outcomes suggest that the values of and both decline, but the anisotropy of surface roughness is enhanced at an increased . The DED model is able to properly reflect the decay behavior in which the morphology roughness is classified into three corrugated components based on their distinct attenuation laws. A satisfactory agreement with the literature data is observed, validating the presented methodology. The reported findings in this work are useful for enhancing the understanding of the formation of crack morphology roughness and its relationship to the damage process of SFRC.

中文翻译：

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使用双指数衰减模型评估断裂钢纤维混凝土中与采样间隔相关的粗糙度


本研究引入了双指数衰减 (DED) 模型来研究钢纤维混凝土 (SFRC) 中裂纹形态粗糙度的采样间隔 () 相关行为。 3D 数字形态中方向导数的均方根 () 用于量化粗糙度及其各向异性行为。使用激光扫描仪捕获 24 个断裂试样的表面形貌，并根据点克里金算法对所得结果进行重新网格划分。粗糙度由表面积与投影面积之比 () 以及沿不同方向在不同 s (4–3000 µm) 下的值表示。结果表明 和 的值均下降，但表面粗糙度的各向异性随着 的增加而增强。 DED 模型能够正确反映衰减行为，其中形态粗糙度根据其不同的衰减规律分为三个波纹分量。观察到与文献数据的令人满意的一致性，验证了所提出的方法。这项工作中报告的发现有助于增强对裂纹形态粗糙度的形成及其与钢纤维混凝土损伤过程的关系的理解。