DIGEST 2006 - Sabita

testing results and very successful
field performance to date.
Experience with this mix design
methodology goes back to CTIA
taxiway mixes placed in 2001/2.
To date an equivalent 300 000 x
22-ton wheel loadings (1 400 kPa
tyre pressures), or an equivalent
of 250 million E80’s, was carried
without any deformation or
durability problems.
Previously, the conventional
“middle of envelope” mixes utilised
at the Much plant at Benoni
(before 2003) showed MMLS
values of ±3 to 3.5mm rutting.
After compositional modification in
accordance with the fundamental
design methodology utilised in this
study, this was changed (as listed
above) to high performance rut
resistant mixes – however, it is
still “binder-rich” (due to good
VMA values in the region of 16%)
and therefore still has good fatigue
resistance and durability.
A full scale APT evaluation of trail
sections of these mixes is planned
for mid 2007 and an update of
these results can then be reported
to the industry.
References:
1
F.J. Pretorius, K.J. Jenkins, F. Hugo,
D. Vietze: Innovative Asphalt Mix
Design and Construction : Case studies on
CTI Airport and Kromboom Parkway.
Paper presented at the 21st ARRB and 11th
REAAA Conference, Cairns,
Australia, 2003
2
K.J. Jenkins, F.J. Pretorius, F. Hugo,
R. Carr: Asphalt Mix Design for
Cape Town International Airport using
scaled APT and other selected tests.
6th International RILEM Symposium on
Performance Testing and Evaluation of
Bituminous Materials, PTEBM’03, Zurich,
Switzerland, 2003
3
F.J. Pretorius, J.E. Grobler, J. Onraët:
Development of a Fit-for-Purpose Product
Performance Specification System for
Asphalt Mixes. Paper presented at
CAPSA'04, Sun City,
South Africa, September 2004
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