What does "gradation" refer to in the context of aggregate bases?

Gradation in the context of aggregate bases specifically refers to the distribution of different particle sizes within a given sample of aggregate material. This distribution is crucial because it affects the compactness, stability, and drainage characteristics of the aggregate base when used in construction. A well-graded aggregate will contain a range of particle sizes, allowing for efficient packing and minimizing voids, which can lead to improved performance of the base material.

Moisture content pertains to the amount of water present in the aggregates and impacts the handling and compaction of particles but does not define gradation. Methods of sampling aggregates refer to how samples are collected for testing rather than the characteristics of the aggregates themselves. Templates for testing aggregates are tools or guidelines used during the testing process, not a characteristic of the aggregates. Thus, the focus on the distribution of different particle sizes is what makes the concept of gradation particularly significant in aggregate base applications.