INSIGHT
RESEARCH TO BENEFIT
PRECASTERS
A joint initiative of the City of Cape Town and the Southern
Africa Readymix Association (SARMA) is underway to research
the effective usage of treated effluent water to manufacture
concrete and concrete products.
U
ntil now, no specific standards
exist to allow the use of water
other than ‘potable’ water to be
used in the process. However,
the recent drought in the Cape Town region
has spurred concerned SARMA members to
join forces with Cape Town Municipality to
work together to use treated effluent water
that might otherwise be lost to the region.
According to SARMA director, Johan
van Wyk, if a suitable solution can be found
it will not only have a positive effect on
water supplies and the environment but
also provide reduce the cost of water for
construction by as much as 75%.
Van Wyk explains, “In this instance
treated effluent water does not refer to
sewage but rather to water from sewerage
plants that has gone through all cycles
of treatment except naturalisation in a
maturation pond. This type of water is often
used for irrigation and is not disallowed
By Eamonn Ryan
SARMA director, Johan van Wyk.
according to national standards nor is
provision made for it in SANS 51008 water
for making concrete because, until now, no
specific testing has been done.
“As a result, we are currently compiling
a testing regime which will enable us to
run an eight-week study and collate results
including water chemistry and all the
parameters surrounding the water and then
monitor its effect on the mixing, setting,
curing and strengths of the concrete.
“This will then be compared with current
concrete standards and data to make a
finding. And, it must be said, that our
preliminary findings are positive and gives
hope for a major evolution in the way we
make concrete in dry climatic regions,” says
Van Wyk.
Seeking alternatives
A concrete plant.
42_QUARRY SA| NOVEMBER/DECEMBER 2018
The construction industry is a major
water user and in the case of concrete
manufacture cannot continue without
a reliable supply of water. Where water
shortage occurs in can either lead to the
closure of concrete manufacturing plants
or to manufacturers seeking alternative
methods of obtaining water. In the Cape
the drought even led to manufacturers
sinking hundreds of boreholes though the
region which can eventually lead to the
concentration of salts that can render the
water unusable for drinking or agriculture
for future generations.
“As guardians of future generations,
we feel it is our responsibility to find
sustainable alternative means of
manufacturing concrete which in turn
plays a significant role in shaping our future
and building infrastructure for the next
generations.
“The finding will be made available
on completion of the research and best
practices will be shared with all concrete
manufacturers via internal communications,
as well as all forms of media at our disposal,”
Van Wyk concludes.