Housing in Southern Africa July 2016

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July 2016
Guinevere
Thomas
Cement & Concrete
Mariana
Lamont
A ll Southern Africa Readymix As-
sociation (Sarma)members are
required to have the necessary
knowledge and correct processes in
place to manufacture concrete, ac-
cording to strict criteria.
In addition, they have access to
technical knowledge that allows
them to manipulate mixes to meet
the customers requirements. Sup-
pliers are also in a position to advise
on the required properties and best
mixes to get the job done, quickly and
efficiently.
“This is all part of Sarmamembers
being proactive and adding value.
The contractor may or may not be
aware of the importance of effectively
specifying concrete,” explains Johan
van Wyk, Sarma General Manager.
“As a progressive industry it is our
job to enlighten our customers and
ensure that apart from the basics,
they also get concrete that is easy to
work with, appropriate for the task
and is tailor made. For example, if the
concrete has to be transported long
distances on site via wheel barrow,
the ready mixer may need to retard
setting a little in order to allow time
to place the concrete, etc.”
He says, “There are many other
Quality concrete on site
‘tricks’ that can be used to make
placement easy, save time andensure
the highest strength and quality.
It’s all about communication and
ensuring that the readymix supplier
understands each and every param-
eter of the usage of the concrete on
site. A Sarma accredited supplier will
be able to add far more value than
merely sticking to a strength and
slump specification,” says van Wyk.
He recommends the following cri-
teria be discussed with the concrete
supplier upfront in order to draw up
an adequate specification: strength
requirements; workability require-
ments; application (know where it
is being used i.e. structural column,
floor etc.); location (address, coordi-
nates, which entrance, details etc.);
contact person; time required on site;
access requirements; and site trans-
port (wheel barrows, pump, bucket
etc.) On receiving concrete van Wyk
suggests that all the resources be
ready and that the truck spins for at
least five minutes on site before dis-
charging. Upon discharge ensure that
all requirements on site are in place
(rebar has been inspected, formwork
inspected, etc.) and that necessary
testing be done according to agreed
methods by nominated persons.
Upon placement ensure that
compaction is done correctly (to get
the air out) and that protection and
curing methods are put in place im-
mediately.
He advises that communication
is critical with all parties on site and
that ready mix staff be consulted to
ensure that everything is going ac-
cording to plan.
“As long as these basics are in
place, the readymix company canpre-
pare mixes in accordance with these
requirements. On site, cooperation
and communication will make the
jobmuch easier,” concludes vanWyk.
For further information con-
tact Sarma on 011 791 3327 or visit
■
Apart from basic strength and slump parameters, contractors can
make use of the knowledge that readymix suppliers can provide in
terms of ease of delivery to the required point, concrete placement
and workability.
Johan van Wyk