Asphalt Aggregate Soil

Asphalt soil is the dirt layer that gets packed down under an asphalt driveway or road before the black asphalt goes on top. It's usually sandy dirt with small stones mixed in, screened clean of roots and wood so it compacts hard and lets water drain. When a truck rolls over the finished pavement, this packed layer is what actually carries the weight through the asphalt above it.

Different jobs call it different names. Contractors say subgrade when it's the very bottom of the road, embankment fill when they're building the ground up to the right height, or paving prep soil when it's the last layer before base rock goes down. It costs less per yard than crushed stone because it's screened dirt, not crushed rock. Ask your driver what grade you need for the job before you order.