Which term describes the distribution of particle sizes in the aggregate blend?

• A. Skid Resistance
• B. Location of Plant
• C. Source and Grade of Materials
• D. Aggregate Gradation

Answer: (D)

Understanding how particle sizes are spread out in the aggregate blend is the key idea here. The term Aggregate Gradation describes that distribution—how many fines, sand, gravel, and larger fragments are present and in what proportions. This is usually determined with sieve analysis and gradation curves, and it directly influences how the particles pack together, affect void content, density, workability, and the overall performance of the asphalt mix. A well-graded blend fills spaces efficiently, helping achieve good compaction and durability, while poor gradation or gap-graded mixes can leave too many voids and lead to stability or durability problems. Skid resistance is about surface friction, not size distribution; Location of Plant is about where the materials are produced; Source and Grade of Materials concerns origin and quality, not how the particle sizes are distributed.