[dad911]

If you spread millings and roll/compact them on a hot day, they make a good base.

However, NJ DEP: The bitumen binder used in asphalt paving applications contains a relatively large concentration of a family of carcinogenic compounds which can pose serious human health and environmental concerns in certain circumstances such as when asphalt material is ground into very small particles that easily blow off of or wash from the surface. These compounds, known as polycyclic aromatic hydrocarbons (PAHs) are specified as targeted pollutants by the U.S. Environmental Protection Agency (USEPA), and are present in asphalt at much higher levels than the criteria established by the DEP for general use in a loose fashion on land. Asphalt millings used alone without a paved top surface have the potential to significantly migrate from the roadway through the actions of water, wind, and physical displacement and possibly contaminate surrounding soils and/or surface water sediments.

So I can't use millings in new construction, but just found out crushed concrete may be ok. I'm looking at that option now.