Abstract Petrographic analysis is routinely implemented to measure air void parameters for predicting freeze-thaw durability of concrete. The 1D or 2D measurements obtained from polished concrete sections are used to infer 3D protection of the paste. Since an arbitrary point in a section view may be partially protected by air voids that are not intersected, a stereological model is proposed to consider both intersected and un-intersected voids. The model is tested with a group of concrete mixtures with varying air entrainment, mix proportion, and aggregate type. As compared with the 2D analysis, this 3D analysis indicates a higher percent of cement paste being protected. When equating the protection range to Powers' spacing factor, it is found that roughly 98% of paste is protected in 3D. Findings in this study also align with results obtained by other authors using numerical simulation and computed tomography. This model offers a realistic concrete freeze-thaw assessment.

中文翻译：

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混凝土冻融保护的 3D 岩相分析

摘要 岩相学分析通常用于测量空气空隙参数，以预测混凝土的冻融耐久性。从抛光混凝土部分获得的 1D 或 2D 测量值用于推断膏体的 3D 保护。由于剖面视图中的任意点可能会被未相交的空隙部分保护，因此提出了一种体视模型来考虑相交和未相交的空隙。该模型使用一组具有不同加气量、混合比例和骨料类型的混凝土混合物进行测试。与 2D 分析相比，该 3D 分析表明水泥浆受到保护的百分比更高。当将保护范围等同于 Powers 的间距系数时，发现大约 98% 的焊膏在 3D 中受到保护。本研究的结果也与其他作者使用数值模拟和计算机断层扫描获得的结果一致。该模型提供了现实的混凝土冻融评估。