ITEM 424 FINE GRADED POLYMER ASPHALT CONCRETE
424.06 Spreading and
Finishing
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. Provide SBR
conforming to 702.14. Provide mineral filler conforming to 703.07.
Provide binders conforming to 702.01.
Ten percent
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
Sieve |
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.
(4) Coarse
Aggregate - For
medium mixes, use 10 percent two-faced crushed aggregate by weight of total
aggregate. For heavy mixes, use 100 percent two-faced crushed aggregate.
Provide two-faced crushed aggregates conforming to ASTM
D5821-95.
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) as required for good workability.
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 and Finishing. 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.
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).
424.10 Basis of Payment. The Department will make payment for accepted
quantities, completed in place, at the contract price for 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