Use of Stone Mastic Asphalt on Airport Pavements - aaptp

7. Discussion
Research into the use <strong>of</strong> stone mastic asphalt (SMA) on aircraft pavements was
undertaken through consultation with in the order <strong>of</strong> 400 airports, contractors,
asphalt producers and suppliers <strong>of</strong> stone mastic asphalt (SMA) around the
world. The list <strong>of</strong> those contacted during the course <strong>of</strong> this research is
contained in Appendix E. The response to the questionnaire was limited to in
the order <strong>of</strong> 20%.
This thesis involved research into technology and processes which contractors
and other organisations involved in the design, manufacture, supply and laying
<strong>of</strong> SMA keep as a closely guarded commercial secret, both in Australia and
around the world. Hence apart from the language barrier, information on
actual experience with SMA on aircraft pavements was extremely difficult to
obtain.
Whilst SMA is used on roads in some 25 countries around the world (the
majority being in Europe), airport usage is limited to 15 countries, again the
majority being in Europe. Of these, Norway is the single biggest user with
some 15 airports using the material on aircraft pavements.
The airport industry as a whole is very cautious regarding new surfacings. The
risk <strong>of</strong> foreign object damage (FOD) to aircraft jet engines cannot be over
emphasised and loose aggregate must be avoided at all times. Hence there is a
resistance to use new materials, particularly on runways, which depart from
normal practice.
The major obstacles facing the use <strong>of</strong> SMA on aircraft pavements would seem
to be client inertia or conservatism. This is the normal reaction to the use <strong>of</strong>
new materials at an airport without the benefit <strong>of</strong> seeing the performance <strong>of</strong> the
material in place.
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