Type 32-33 crushed gravel, or compaction gravel, is a mix of rock, gravel and clay. This combination gets processed through a rock crusher to create fractured stones, which develops the ultimate compaction product. Compaction gravel is a base layer used to strengthen the structure of roads, driveways and gravel parking lots, as the fractured stone combination creates a good binder. It also reduces the stress on the sub grade layer and provides drainage.