ITEM 301 ASPHALT CONCRETE BASE
301.04 Spreading and Finishing
301.05 Spreading and Surface Tolerances
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) |
100 |
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 401.04. The 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), and that the mix temperature 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)