Asphalt-treated base (ATB) is also known as asphalt-stabilized base (ASB), or simply “black base.” For the HMA options, lower layers are allowed to contain higher percentages of recycled products and a lower quality aggregate with less stringent material specification requirements as compared to surface mixtures. Standard mix design, production, placement, and field acceptance procedures govern these base mixtures in accordance with the applicable specification. These materials are ready to be trafficked as soon as compaction is completed and temperature is below 160°F, but the cost is high compared to other treated base options.

Where long-term moisture susceptibility of HMA and asphalt-treated base (ATB) is a concern, using a plan note to increase the target laboratory density or decrease Ndesign (and thus increase asphalt content) may be beneficial.