Which scale should be observed for aggregate size selection in grading operations?

The gradation scale is fundamental for aggregate size selection in grading operations because it provides essential information about the distribution of particle sizes within the aggregate. This scale helps determine how well the aggregate will perform in construction applications, particularly in terms of stability, load-bearing capacity, and workability.

In grading operations, having the right distribution of different aggregate sizes ensures proper compaction and minimizes void spaces. This is crucial for achieving optimal strength and durability in the final product, whether it be asphalt, concrete, or a sub-base for roads. The gradation scale allows engineers and contractors to select aggregates that meet specific criteria established for different construction purposes, thereby ensuring the overall quality and longevity of the project.

Other scales, such as moisture, compaction, and weight scales, play important roles in construction processes but do not specifically address the size characteristics of aggregates needed for effective grading operations.