Abstract The representative volume element (RVE) plays an important role in the mechanics and physics of random heterogeneous materials with a view to predicting their effective properties. Estimating the RVE size, therefore, is of high importance. In this paper, potassium iodide (KI) was applied first time as the staining agent, and local sand fraction of mortar was calculated combining staining technique and computed tomography (CT). Besides, an extended attenuation method was refined in this study, and spatial distribution of local porosity for mortars was obtained. The RVE size was estimated depending on gray-scale value, local sand fraction and local porosity, respectively, and the results reveal that, the RVE size depending on gray-scale value is smaller than that depending on local porosity or depending on local sand volume fraction; besides, both the RVE sizes depending on local sand fraction and depending on local porosity comply with that obtained from numerical modelling, where a RVE size is suggested to be 3–5 times greater than the maximum sand size.

中文翻译：

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使用断层扫描来估计碘化钾染色的砂浆中的代表性基本体积

摘要 代表性体积元（RVE）在随机异质材料的力学和物理学中起着重要作用，以预测它们的有效性能。因此，估计 RVE 大小非常重要。本文首次采用碘化钾（KI）作为染色剂，结合染色技术和计算机断层扫描（CT）计算砂浆局部砂粒分数。此外，本研究改进了扩展衰减方法，获得了砂浆局部孔隙率的空间分布。分别根据灰度值、局部砂粒比例和局部孔隙度估计 RVE 尺寸，结果表明，取决于灰度值的 RVE 尺寸小于根据局部孔隙度或局部砂体积的 RVE 尺寸分数;