Definition
Gravel is a loose aggregation of rock fragments used in construction for drainage, base material, driveways, and landscaping. Gravel is categorized by size: #57 (3/4 inch) for concrete and drainage, #4 (1-2 inch) for drainage bases, crusher run (mixed sizes) for driveways, and pea gravel (3/8 inch) for walkways and decoration. A cubic yard of gravel weighs approximately 2,700-3,000 pounds depending on moisture content and rock type.
Formula
Gravel compacts approximately 10-15% when placed. Account for this by ordering 10-15% more than the loose volume. For driveways, use 4-6 inches of #57 or crusher run gravel. For concrete base, use 4-6 inches of #57 stone. Always use a geotextile fabric barrier between soil and gravel to prevent mixing and extend gravel life.
Example
Driveway Gravel Example
A 12x40 foot driveway requires 6 inches of crusher run. Volume = 12 x 40 x 0.5 = 240 cubic feet. With 15% compaction, order 276 cubic feet or approximately 10.2 cubic yards. A standard dump truck carries 10-15 cubic yards, so one truckload should suffice for this project.