Hot Rolled Asphalt and Asphalt Concrete (Macadam) - Ministry of ...

Specification 12 Hot Rolled Asphalt and Macadam Appendix Z – Guidance Notes on the Preparation
for Airfields of Job Specifications
TABLE Z.2 TRAFFICKING LIMITATIONS ON THE USE OF ASPHALT CONCRETE (MACADAM)
Tyre Pressure Frequency of Trafficking
Low Medium High
MPa (psi) Binder Surface course Binder Surface course Binder Surface course
course Recipe Design course Recipe Design course Recipe Design
up to 0.7 (100)
0.7 to 1.4 (100 to 200)
More than 1.4 (200)
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
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Yes
Yes
No
Yes
No
No
Yes
Yes
Yes †
Yes Asphalt Concrete (Macadam) is permitted for that course.
No Asphalt Concrete (Macadam) is not permitted for that course.
Yes † Design Asphalt Concrete (Macadam) is permitted for small works only, subject to prior advice being
sought from Professional and Technical Services, DE.
Z.2.2 The frequency of trafficking is as defined
in sub-Clause Z.1.2.
Z.3 USE OF PERVIOUS MACADAM
Pervious Macadam is used as a topping to protect
French drains.
Z.4 RESISTANCE TO FREEZING AND
THAWING OF AGGREGATES
For small works, the magnesium sulfate test on all
fractions can be omitted provided there is local
evidence that the aggregate has adequate
resistance to freezing and thawing. In such
cases, the standard BS EN 1367-2 magnesium
sulfate test conducted on the 10/14 mm size
fraction may be considered satisfactory and it is
unnecessary to require testing in accordance with
Appendix A.
Z.5 PSV CATEGORY FOR SURFACE
COURSES
Z.5.1 The requirement for the resistance to
polishing of coarse aggregate on runway surface
courses should normally be Category PSV50. For
high frequency traffic (as defined in Sub-
Clause Z.1.2), a requirement for PSV of Category
PSVdeclared 55 should be set.
Z.5.2 The requirement for the resistance to
polishing of coarse aggregate on taxiway surface
courses should be Category PSV44. However, for
low frequency traffic (as defined in Sub-
Clause Z.1.2), the category PSVNR may be used
except for fast exit taxiways.
Yes
Yes
No
Yes
No
No
Yes
Yes
Yes †
Z.6 STABILITY OF DESIGN HOT
ROLLED ASPHALT AND ASPHALT
CONCRETE (MACADAM)
MIXTURES
The Hot Rolled Asphalt design mixtures specified
in Clause 4.5 would be expected to provide a
higher stability than the Asphalt Concrete
(Macadam) mixtures specified in Clause 4.4.
Z.7 HOT ROLLED ASPHALT AND
ASPHALT CONCRETE (MACADAM)
DESIGN MIXTURES
Z.7.1 The minimum stability requirements for
Hot Rolled Asphalt and Asphalt Concrete
(Macadam) design mixtures should be selected
according to Table Z.3.
Z.7.2 The frequency of trafficking is as defined
in Sub-Clause Z.1.2.