The Civil Engineering Contractor October 2018 | Page 24

ON SITE
Sustainable structural
shotcrete saves time
Professionally placed wet shotcrete
was chosen as the preferred method
to apply concrete for a tricky
8m-high, 400mm-thick retaining
wall for new digs being built in
Braamfontein by Liviero Building, to
save time and space.
“In today’s increasingly competitive
and challenging structural concrete
marketplace, the need for innovative
solutions to challenging forming
issues is greater than ever,” says
Dustin Strever, director of
Shotcrete Africa. The marketplace
is seeing greater acceptance of wet
shotcrete as a logical and efficient
option for structural concrete
applications, with the added benefits
of sustainability and environmental
responsibility.
Structural shotcrete offers a
number of compelling advantages:
substantially less formwork is
required; and the formwork that is
required is considerably lighter in
weight.
Strever says the reason for it winning
the concrete application contract for
the South Point Bertha Avenue/
Jorissen Street development was
primarily the saving in time. “Our
application methodology meant
that 80m 3 of concrete could be laid
in two days without the need for
formwork, whereas the traditional
methodology of form-and-pour
would have taken just over 10 days
to erect the shuttering and place
the concrete using the on-site crane
and a concrete kibble. There was a
difficult and congested working area
and we were able to allow the other
contractors to continue working
while we completed our scope.”
One advantage of wet shotcrete is
that it can be placed in difficult,
tight-to-reach areas.
Strever mentions that in this case,
the cost of the shotcrete option was
approximately 15% higher than the
on-site allowable, “but allowables
don’t take into consideration the
real savings in time, crane, and other
plant and equipment”.
22 - CEC October 2018
A recent concrete application.
Applying a smooth finish.
“We can accelerate the pace of
projects, and in this instance saved
Liviero 10 days on only 80m 3 . Imagine
what could be saved time-wise on an
8 000m 3 contract, though both wet
shotcrete and dry shotcrete (gunite)
methodologies are both equally
excellent ways of placing concrete.”
Each has its own definite advantages
and disadvantages. Dry shotcrete
must not be used in thick structural
elements due to high rebound and
fluctuating w/c ratios; however, it is
a superlative concrete repair method.
One reason why shotcrete is not as
well supported as i