southern AFRICA news
The burner heats the aggregate at the feed end of the
mixing drum before it is coated with bitumen towards
the discharge end.
Much Asphalt uses high-quality dolerite at eMalahleni plant
High-quality dolerite aggregate
from B&E International’s
Howards Quarry outside
eMalahleni is keeping Much
Asphalt’s nearby static plant
— one of 15 static plants the
company operates around
South Africa — well stocked
to produce asphalt for the N4
highway project and other
developments as far away
as Nelspruit.
Recent infrastructure upgrades
at the eMalahleni asphalt plant
— which was initially adapted
and enlarged from a mobile plant
— have included an improved
conveyor system and storage
silos. The plant can also treat
recycled asphalt in new asphalt
mixes, incorporating between
10% and 20% recycled asphalt.
As one of southern Africa’s
largest commercial suppliers of
hot and cold asphalt products,
Much Asphalt keeps a close
eye on the standards and
the specifications of both
its ingredients and its final
product, according to its
eMalahleni branch manager,
Gavin Roos.
“The quality of stone we
use is an important aspect of
asphalt production, as it gives
the road its strength,” says
Roos. “Dolerite is particularly
good for asphalt because it’s
a strong stone and it doesn’t
crush under weight, so it is able
to withstand the heavy truck
traffic that our highways must
endure without deteriorating.”
Much Asphalt takes samples
from source quarries and sends
them for specialised laboratory
testing to establish whether
the key aspects — fraction
sizes, aggregate crushing value
(ACV), permeability, adhesion,
and moisture content — are
suitable for the planned use
and in line with Committee of
Land Transport Officials (Colto)
standards.
Howards Quarry trucks in
supplies daily so that Much
Asphalt always has substantial
stockpiles; this helps in
retaining a consistency of
aggregate, which is blended on
site by means of a pay-loader.
“Independent tests verify that
this hard rock dolerite source
is far superior to anything
else found in the region,” says
Howards Quarry manager
André Kamfer.
Daily testing is done at
the on-site laboratory after
every 100 tonnes of aggregate
delivered, to determine sand
equivalent, fines, grading, and
other factors that affect the
recipe for high-quality asphalt.
Adjustments are then made
based on the results to achieve
a final grading that aligns
with the company engineers’
specifications and, for roadwork
applications, is in compliance
with Colto standards.
Equipment at the on-site
laboratory is regularly checked
against Much Asphalt’s SANAS-
accredited main laboratory in
Cape Town, and the company’s
regional laboratory in Benoni
is used for more technical tests
on both aggregate and bitumen.
Gavin Roos, eMalahleni branch manager for Much Asphalt, in the
on-site laboratory.
QUARRY SA | SEPTEMBER 2017 _ 5