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Asphalt Concrete Base (ACB)

Asphalt concrete base (ACB) is a dense-graded HMA with a larger nominal maximum aggregate size (1 inch) intended for use as a base course or binder course (see Figure 1). The term "Asphalt Concrete Base" is used in this manual to describe both HDOT's Hot Mix Asphalt Base Course (HMAB Course) and the County Asphalt Treated Base (ATB) mixtures. It can be known by different names in Hawai'i (HDOT calls it HMAB Course and Honolulu calls it ATB) but it is essentially the same material. In addition to site paving benefits, ACB can be advantageous because it can provide:

Asphalt concrete based used on Maui

Figure 1: 6-inch ACB layer under 1.5 inches of State Mix IV (coin shown is a quarter).

The costs savings of using ACB can add up quickly. On a site that must export material (excess cut), an ACB pavement design can save a considerable amount of excavation, hauling and disposal costs. On a site that must import material (excess fill), ACB can be used to build the pavement over more marginal subgrades (i.e., a structure of gravel borrow and ACB can replace thicker crushed aggregate sections).

Important Considerations when Substituting ACB for Untreated Crushed Aggregate Base

Other ACB Information

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