For reaching high packing fractions, grains of various sizes are often mixed together allowing the small grains to fill the voids created by the large ones. However, in most cases, granular segregation occurs leading to lower packing fractions. We performed a wide set of experiments with different binary granular systems, proving that two main parameters are respectively the volume fraction f of small beads and the grain size ratio α. In addition, we show how granular segregation affects the global packing fraction. We propose a model with a strong dependency on α that takes into account possible granular segregation. Our model is in good agreement with both earlier experimental and simulation data.

中文翻译：

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尺寸比和偏析如何影响二元颗粒混合物的堆积。

为了达到较高的堆积率，通常将各种尺寸的颗粒混合在一起，使小颗粒填充大颗粒所形成的空隙。但是，在大多数情况下，会发生颗粒分离，从而导致较低的填充率。我们使用不同的二元颗粒系统进行了广泛的实验，证明了两个主要参数分别是小珠的体积分数f和晶粒尺寸比α。此外，我们展示了颗粒分离如何影响整体填充率。我们提出了一个对α有很强依赖性的模型，该模型考虑了可能的颗粒偏析。我们的模型与早期的实验和仿真数据都非常吻合。