How does the gradation of a mix affect asphalt pavement?

The gradation of a mix significantly impacts compaction because it determines the distribution of particle sizes within the asphalt. A well-graded mix contains a range of aggregate sizes that allows the particles to fit closely together, facilitating better interlock during the compaction process. This allows for more effective compaction, resulting in a denser and more stable pavement structure.

If a mix is poorly graded, with either too many fine or too many coarse aggregates, it can lead to inadequate compaction. Poor compaction can affect the pavement's strength and longevity, leading to premature distresses such as cracking or raveling. Thus, achieving the appropriate gradation is crucial for optimizing the compaction process, which directly influences the overall performance of the asphalt pavement.

The other factors mentioned in the options do not have a direct relationship with gradation as it pertains to the structural characteristics of asphalt pavement. For instance, while gradation may slightly influence color and flexibility, these aspects are not as critical to pavement performance as the impacts on compaction.