The Hazen Uniformity Coefficient (Cu) indicates what about particle size distribution?

The Hazen Uniformity Coefficient (Cu) is a measure used in soil mechanics and civil engineering to describe the particle size distribution of granular materials, particularly soils. It is defined as the ratio of the diameter of the particle at the 60th percentile to the diameter at the 10th percentile. Specifically, it is calculated using the formula Cu = D60 / D10, where D60 is the particle size at which 60% of the sample's mass is composed of smaller particles, and D10 is the particle size at which 10% of the sample's mass is composed of smaller particles.

The Cu provides insight into the uniformity or variability of a material's particle sizes. A higher Cu value indicates a wider range of particle sizes, suggesting a more poorly graded material, while a lower Cu value indicates that the material has a more uniform particle size distribution. This attribute is crucial for understanding the behavior of soils and aggregates in engineering applications, such as drainage, filtration, and stability assessments. Therefore, the correct answer accurately reflects the role of the Hazen Uniformity Coefficient in characterizing the shape of the particle size distribution.