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CONSTRUCTION WORLD
AUGUST
2016
I
>
PRODUCTS AND SERVICES
Roxburgh says detailed specifica-
tions for structural concrete work
and industrial floors on the ground
are essential to prevent prob-
lems during the construction and lifespan
of a concrete structure. In the design and
construction of concrete structures, both the
plastic and hardened state properties should
be considered.
“A contractor is inclined to be more
concerned about the plastic state of concrete
which, if designed with construction methods
in mind, will simplify the job and achieve
better results when the shutters are removed.
An engineer, on the other hand, often places
more emphasis on the hardened properties of
concrete: it must meet the strength require-
ments and be durable and free from defects.
“But the contractor, engineering
consultant and clients can all win if the
specifications – whether prescriptive or
performance-based – are correct, detailed
enough and, importantly, cover not only the
performance of the finished product but also
concrete mix design, transport, construction
methods and the plastic state of the concrete.
In the case of industrial floors, in particular,
detailed specifications for joint types and
layout are essential, as is the specification for
the concrete to ensure appropriate perfor-
mance,” Roxburgh stated.
“Fundamental to obtaining the correct
performance out of any concrete structure is
the concrete mix design. However, even with
the correct mix design, there are many things
that can go wrong between batching and
completion of the hardened product.
The plastic properties of the concrete must
suit both the transport and construction
methods employed as well as the finish
required when it comes to industrial floors.
The construction process, in particular,
should be carefully thought through to opti-
mise the performance of the concrete.
A large percentage of strength and durability
problems start in the plastic phase of the
concrete but with good specifications and site
practice these can be avoided.
“Protection and curing are aspects that
are often under-specified, especially in the
case of industrial floors and pavements
which have large surface areas relative to
concrete volume and are therefore prone to
drying, especially during finishing. Curing
is important for concrete strength but can
also prevent defects such as cracks, surface
Need for
DETAILED
KNOWLEDGE
about concrete
South African engineers and contractors need detailed
knowledge about the properties and construction requirements
of concrete to prevent incorrect specifications for building
projects, says John Roxburgh, lecturer at The Concrete
Institute's School of Concrete Technology
John Roxburgh, lecturer at The Concrete
Institute's School of Concrete Technology.
>
Advantages of Sika AnchorFix
®
-S:
• Chemical anchoring is much more effective than mechanical
anchors:
• No expansion – no cracking of substrates
• Outstanding load bearing capacity
• Corrosion prevention
• Easy application: With an open time of three to four minutes, the
applicator ensures a flexible working time. Due to the styrene in
this product, a long application time is provided while fast curing
speed is maintained - useful especially in high temperatures and
tropical climates.
• Non-Sagging: Sika AnchorFix
®
-S displays non-sagging
behavior for both horizontal and vertical applications.
Thanks to the easy-to-handle and highly efficient
packaging and mixing mechanism, unnecessary waste of
product is avoided.
• Versatile: Sika AnchorFix
®
-S can be utilised for fixing of
sanitary equipment and the installation of kitchen fittings,
aerials and satellites. Among the common applications
in metalwork are general supports, window and
doorframes, window protection cages, blinds, sunshades
and handrails. Used extensively for rebars/reinforcing
steel, threaded rods, bolts and special fastening systems.
• Sika AnchorFix
®
-S is suitable for use in concrete, hollow
and solid blockworks and bricks as well as in hard natural
stone and solid rock. Both outdoor and indoor applications are
possible. It can be used for fixing both structural elements (such
as balcony extensions) and non-structural elements (e.g. stair and
balcony railings or sun blinds).
• Sika AnchorFix
®
-S is the ideal solution for applications using hollow
blocks. Where mechanical anchors are ineffective as they loosen,
the Sika AnchorFix
®
-S system is combined with a perforated sleeve
to ensure it stays fixed.
FAST-CURING UNIVERSAL ANCHORING ADHESIVE
Sika has extended its offering in the Anchoring
range. This NEW two-part, general-purpose,
anchoring adhesive is based on styrenated
polyester and is intended for mechanical, electrical
and plumbing works, as well as metal or structural
work. Sika AnchorFix
®
-S covers the requirements
for standard applications of low to medium loads.
wearing and quality. Durability is also greatly
enhanced with proper curing. Sadly, too often
curing and surface protection are inadequate
because of a lack of suitable specifications. By
far the greatest number of enquiries received,
and consultations carried out, by The
Concrete Institute deal with problems with
industrial floors and pavements. These prob-
lems stem from a lack of knowledge about
concrete design, detailing and construction.
“It is therefore essential for both engi-
neers and contractors to fully understand
the properties of concrete and construction
requirements of different structures to
produce appropriately detailed specifica-
tions for concrete works. These subjects are
dealt with in the two one-day courses the
School of Concrete Technology is offering.
‘SCT36 Properties of concrete for the struc-
tural designer and constructor’ and ‘SCT21
Concrete industrial floors on the ground’
are available on pre-set days according to
the School of Concrete Technology's annual
training programme. Companies can arrange
for the School to present the courses on
specific dates and venues and use this option
as a marketing tool by inviting clients and
associates to attend,” Roxburgh stated.