| Material |
Description |
Nominal
Size |
Road
Use |
| Hot
Rolled Asphalt (HRA) |
This
material is made up of crushed rock or sand mixed with
a bitumen binder and mineral powder (filler) to form a
dense asphaltic cement. Course aggregate is added to
increase the stability of the mix.
The type of mix is
classified as a percentage of course aggregate to the
mix.
30/14 = 30% aggregate of
14mm nominal size.
The hardness and
worability of the material is determined by the
penetration value of the bitumen, 50 PEN would be a
stiffer mix.
Pre-coated chippings are
used to provide texture depth and skid resistance.
|
14mm |
Wearing
Courses
for Type 1 - 4 roads |
| 20mm |
Basecourse
and Roadbases
for Type 1 - 4 roads |
| |
| Dense
Bituminous Macadams |
The
material is made up from close graded aggregate coated
with bitumen, no filler is used. The texture depth
will be determined by the nominal size of the
aggregate and the percentage of fines less than
3.35mm. Skid resistance is determined by the PSV of
the aggregate used in the mix.
Open Textured -
fines content not exceeding 25%.
Medium Textured -
10 and 6mm nominal size aggregate and 40 - 60% fines.
Fine Textured -
6mm nominal size with a high percentage of fines.
Dense - up to 46%
fines and stiff binders used to form a dense mix for
heavy duty use. |
6mm |
Wearing
Courses
for Type 3 and 4 roads |
| 10mm |
Wearing
Courses
for Type 1 - 4 roads |
| 20mm |
Base
Course and Roadbases
for Type 1 - 4 roads |
Permanent
Cold Surfacing Materials
PCSM |
This
material is made up with close graded aggregate coated
with a bitumen emulsion. No filler is used. The skid
resistance is determined by the PSV of the aggregate.
Note: Not to be
used as road base material. |
6mm |
Wearing Courses
for Type 3 and 4 roads
|
| 10mm |
Wearing Courses
for Type 2 - 4 roads
|
| 20mm |
Base Courses
for Type 1 - 4 roads
|
| |
| Deferred
Set Macadams |
Made
with single nominal size aggregate coated with a
fluxed bitumen binder. The grade of flux determines
the setting time of the material, this will also be
determined by the ambient air temperature.
This material is only
used as a temporary surfacing material.
|
6mm
10mm
20mm |
Temporary
surfacing as required and replaced with a permanent
surfacing material within 6 months |
