Crusher run is a dense graded aggregate best used for creating a sub base or foundations a combination of crushed stone from 40mm down to dust to create a low void content easily compacted so if used as a loose driveway material it will not shift and separate like a purely gravel driveway if used as a sub base for paving a layer of sand or dust should be used to provide extra support and stability for the slabs delivered in a bulk bag on a pallet onto a solid surface only approximatel