Crushed Stone Applications
Crushed stone (often called "crusher run" or "3/4 minus") is angular, fractured rock that compacts firmly -- unlike round gravel which shifts underfoot. This makes it the standard material for structural base layers under concrete, pavers, asphalt, and buildings. It's also used for drainage trenches and unpaved parking areas.
The angular edges lock together when compacted, creating a stable, load-bearing surface. Compaction reduces the volume by 20-30%, so order accordingly -- 4 inches of loose crushed stone compacts to about 3 inches.
Crushed stone is graded by size. "3/4 minus" means the largest pieces are 3/4 inch and includes all smaller particles (fines). "Clean 3/4" has no fines -- it's used for drainage where water needs to pass through. The calculator handles both based on the same density since they weigh approximately the same per cubic yard.