ITEM 424 FINE GRADED POLYMER ASPHALT CONCRETE
424.01
Description
424.02
Composition
424.03
Materials
424.04 Mixing
424.05 Weather
Limitations
424.06
Spreading, Compacting and Finishing
424.07 Surface
Tolerances
424.08
Acceptance
424.09 Method
of Measurement
424.10 Basis of
Payment
424.01 Description. This work consists of
constructing a surface course of aggregate and polymer modified asphalt binder
mixed in a central plant and spread and compacted on a prepared surface. The
requirements of 401 apply, except as modified by this
specification.
424.02 Composition. For Type A mixes use 8.5 percent
modified asphalt binder by total mix weight.
For
Type B mixes, submit a proposed JMF according to 441.02 to the Laboratory that meets the
requirements of a Type 1 surface course, except as follows:
A.
Minimum VMA, 15.0 percent
B.
Minimum total binder content, 6.4 percent
C.
Design air voids, 4.0 percent
424.03 Materials. Furnish clean, uncoated aggregate
conforming to the applicable requirements of Table 424.03-1
and quality requirements of 703.05.
Use
a PG 76-22M asphalt binder; or a PG 64-22 asphalt binder modified by adding 5.0
±0.3 percent by weight Styrene Butadiene Rubber (SBR)
solids and meeting the requirements of PG 76-22. Provide SBR conforming to 702.14.
Provide mineral filler conforming to 703.07.
Provide binders conforming to 702.01.
Ten
percent reclaimed asphalt concrete pavement may be
used in a Type B mix if all requirements of footnote [3] are met by the
reclaimed asphalt concrete. Do not use reclaimed asphalt concrete
pavement in a Type A mix.
TABLE
424.03-1 - MIX GRADATION
|
|
Total Percent Passing |
|
Sieve Size |
|
Type A [1][2] |
Type B [1][3][4] |
1/2 inch |
(12.5 mm) |
|
100 |
3/8 inch |
(9.5 mm) |
100 |
95 to 100 |
No. 4 |
(4.75 mm) |
95 to 100 |
85 to 95 |
No. 8 |
(2.36 mm) |
90 to 100 |
53 to 63 |
No. 16 |
(1.18 mm) |
80 to 100 |
37 to 47 |
No. 30 |
(600 µm) |
60 to 90 |
25 to 35 |
No. 50 |
(300 µm) |
30 to 65 |
9 to 19 |
No. 100 |
(150 µm) |
10 to 30 |
-- |
No. 200 |
(75 µm) |
3 to 10 |
3 to 8 |
[1]
Gradation includes any mineral filler and is specified in percent
passing.
[2]
Use natural sand with at least 50 percent silicon dioxide by weight
according to ASTM C 146.
Include with a JMF submittal certified test data from
an AASHTO accredited laboratory showing conformance
to the 50 percent silicon dioxide requirement. Ensure data is no more
than one year old at time of submittal.
[3]
Fine Aggregate - Use natural sand with at least 50 percent silicon
dioxide by weight according to ASTM
C 146. Include with a JMF submittal
certified test data from an AASHTO accredited
laboratory showing conformance to the 50 percent silicon dioxide requirement.
Ensure data is no more than one year old at time of submittal. For medium
mixes, use no more than 20 percent limestone sand by weight of total aggregate.
For heavy mixes, use 20 percent limestone sand or air cooled slag sand by
weight of total aggregate. If 10 percent RAP is used the silicon dioxide
content of the total natural sand blend must be at least 50 percent.
Contact the Office of Materials Management, Asphalt Materials section for
guidance on submitting RAP aggregate silicon dioxide data.
[4]
Coarse Aggregate - For medium mixes, for the final blend of all coarse
aggregate use a minimum 10 percent two or more fractured faces aggregate. For
heavy mixes, use 100 percent two or more fractured faces aggregate. Meet the two
or more fractured faces aggregate criteria of ASTM D5821-01 (Reapproved
2006).
424.04 Mixing. Ensure the mixing plant conforms to 402. Discharge the mix from the plant at temperatures
between 335 °F to 370 °F (168 °C to 188 °C) for hot mix asphalt or 300 °F to
340 °F (149 °C to 171 °C) for warm mix asphalt.
424.05 Weather Limitations. Do not
place the asphalt concrete when the surface of the existing pavement is less
than 60 °F or the air temperature is less than 60 °F.
424.06 Spreading Compacting and Finishing. Compact
Type A or B mixes conforming to 401.13 and 401.16. If compacting
a mixture 1 inch (25 mm) thick or less do not use a spreading rate that exceeds
twice the total capacity of the rollers in use. Use a minimum of two
rollers. Do not allow traffic on the compacted mixture until it has
cooled sufficiently to prevent damage.
424.07 Surface Tolerances. Ensure the
completed surface course conforms to 401.19.
Remove
raised pavement markers according to 621.08.
The Contractor may fill the depression caused by the removal of the casting
with material meeting this specification.
424.08 Acceptance. For Type A
mixes comply with acceptance requirements of 301.
For Type B mixes comply with all requirements of 448.
424.09 Method of Measurement. For Type
A mixes use a unit weight conversion of 1.75
tons/cubic yard (2.08 metric tons/cubic meter).
The
Department will measure the number of raised pavement markers removed.
424.10 Basis of Payment. The Department
will pay for removal of existing raised pavement markers according to Item 621 Raised Pavement Markers Removed.
The
Department will make payment for accepted quantities, completed in place, at
the contract price as follows:
Item
Unit
Description
424
Cubic Yard
Fine Graded Polymer
(Cubic Meter)
Asphalt Concrete, Type A
424
Cubic Yard
Fine Graded Polymer
(Cubic Meter)
Asphalt Concrete, Type B