301.01  Description

301.02  Composition

301.03  Mixing

301.04  Spreading and Finishing

301.05  Spreading and Surface Tolerances

301.06  Basis of Payment


301.01  Description.  This work consists of constructing a base course of aggregate and asphalt binder, mixed in a central plant and spread and compacted on a prepared surface.

The requirements of Item 401 apply, except as modified by this specification.

301.02  Composition.  Furnish aggregate for the mix that conforms to the following gradation:

Sieve Size

Total Percent Passing

2 inch

(50 mm)


1 inch

(25.0 mm)

75 to 100

1/2 inch

(12.5 mm)

50 to 85

No. 4

(4.75 mm)

25 to 60

No. 8

(2.36 mm)

15 to 45

No. 16

(1.18 mm)

10 to 35

No. 50

(300 µm)

3 to 18

No. 200

(75 µm)

1 to 7


Submit for the Laboratory’s approval the desired percentage of the aggregate passing the No. 4 (4.75 mm) sieve and blend of individual components. The Contractor may use reclaimed asphalt concrete pavement according to 401.04The Laboratory will establish the required binder content within a range of 4 to 8 percent.  Do not make changes in these JMF values due to unsatisfactory results or other conditions except as authorized by the Laboratory. Obtain a new JMF approval for any desired change to an existing JMF.

301.03  Mixing.  If using a batch plant, use screens with openings of sizes that result in a reasonably balanced separation of the dried and heated aggregate into a minimum of two bins.

301.04  Spreading and Finishing.  Ensure that the maximum compacted depth of any one layer is 6 inches (150 mm).  Ensure that the temperature of the mixture when delivered to the paver is a minimum of 250 °F (120 °C) if a hot mix asphalt and 230 °F (110 °C) if a warm mix asphalt according to 402.04.  Ensure the temperature of the mixture is sufficient for the roller coverage to be effective in compacting the mixture.

301.05  Spreading and Surface Tolerances.  Do not exceed 3/8 inch (10 mm) in surface variation from the testing edge of a 10-foot (3 m) straightedge.  If using Item 301 Asphalt Concrete Base as a subbase for a rigid pavement or base, do not exceed a variation of 1/4 inch (6 mm).

Correct variations in excess of slope or surface tolerances by adding or removing material in a manner satisfactory to the Engineer.  The Contractor may use asphalt concrete approved by the Engineer.

301.06  Basis of Payment.  The Department will pay for accepted quantities, complete in place, at the contract price as follows:

Item           Unit                                Description

301             Cubic Yard                      Asphalt Concrete Base
                       (Cubic Meter)