Which option best represents the processing steps of aggregate?

• A. Excavation and crushing only.
• B. Sizing and stockpiling only.
• C. Excavation, crushing, sizing, and stockpiling.
• D. Shaping and compaction of aggregate.

Answer: (D)

Processing aggregate involves getting the material to the right shape and density so it can perform well in the pavement. Shaping happens during the production steps—crushing and screening—so the rock breaks into particles with a cubic, interlocking form that resists breakage and distributes loads more effectively. But finishing the job requires compaction in the field, where rollers densify the material, reduce voids, and lock the particles together to create a stable base or wearing course.

So, focusing on shaping and the in-place densification (compaction) captures both producing well-shaped particles and achieving the necessary density for performance. The other options miss one or both of these essential aspects: relying only on excavation and crushing, or only on sizing and stockpiling, omits the shaping that improves particle interlock and the compaction that ensures the aggregate reaches the target density in the pavement structure.