ITEM 301 ASPHALT CONCRETE BASE
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) |
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) 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)