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CONSTRUCTION WORLD
APRIL
2017
recycled concrete into the G5, giving us a
good mixture of decomposed material and
returned concrete,” Docrat says. “During our
G5 run to produce the material for sub-base
layers in road making, we began testing by
trickle-feeding a small portion of returned
material into the G5, and found that it
worked well.”
Quality
The first trial was on the Gauteng Freeway
Improvement Project’s N1 extension, where
AfriSam provided G5 for a few runs and the
contractor gave it the thumbs-up; that was
where the success of the idea really started
to prove itself, according to Docrat.
As with all AfriSam products, quality
control and rigourous testing is constantly
required to ensure that it is fit-for-purpose.
The material is sampled first from the
production stockpile. Then, once it is in
the set-back stockpile, it is fully tested for
compliance with the final specification for
G5 product.
“Customers also rely on the fact that all
AfriSam products comply with the South
African Bureau of Standards’ COLTO (Com-
mittee of Land Transport Officials) material
grading specifications,” he says. “Our G5
product containing the recycled concrete
has passed all the necessary quality hur-
dles under the SABS requirements.”
Paving the way
Another successful application for the
returned concrete at AfriSam’s Jukskei
Quarry has been the paving of many parts
of the readymix site.
A concerted effort is underway at the
quarry’s readymix division, where a new
plant is in place, to construct pedestrian
walkways and to pave open areas. This
is likely to consume a portion of the
returned concrete.
“We have already been able to pave large
areas of the readymix site,” he says. “This
is possible when there is a return during
the day, when there are people available
to manage and supervise the pouring of
returned concrete in the appropriate areas.”
The final product after it has been recycled and blended.
This process begins with the preparation of
areas to be paved, so that wet concrete can
be poured into the waiting formwork and
immediately leveled, with expansion joints
left between the slabs.
It is a well-organised process that en-
sures an attractive and functional end-re-
sult, he says.
Environment
Docrat highlights the importance of an
environmentally friendly response to the
issue of returned concrete, as there are
no dumping facilities which accept this
kind or quantity of waste. Recycling also
means no slush around the plant, less
potential for contamination, and a smaller
carbon footprint.
“Our Environmental Management
Programme requires that we achieve a
certain level of recycling in our waste
management strategies, and this
breakthrough in recycling concrete is
certainly a contribution to our performance
in this regard,” he says.
The actual amount of concrete recycled
each month is dependent on sales, which
vary according to the economic climate
and times of year. But he is confident that
the amount of returned concrete that will
be recycled into saleable AfriSam product
could comprise up to 60% of the total
concrete returned to the readymix site.
The recycling process, he says, will
certainly make for a more sustainable
environment; while at the same time
make a contribution toward offsetting
the costs that returned concrete place
on the business.
Preserving the planet
AfriSam’s Jukskei Quarry, one of the
company’s 17 aggregate plant sites
nationwide, produces concrete aggregate,
crusher sand, base and sub-base material.
As part of AfriSam’s corporate
commitment to conserve the planet,
it directs significant effort towards
environmental stewardship. As a result
of ongoing research, the company has
developed a cement product – Eco Building
Cement – that has a carbon footprint of
453 g/kg, which is almost half of the world
average of 890 g/kg.
Waste at the facility that will be recycled.