Concrete
– Can You Afford to Be Without
It?
The Features and
Benefits of Concrete
Concrete
is one of the oldest and most widely used construction materials in the
world
and possesses many unique qualities that benefit the owner, developer
and
designer. Due to its
versatility, aesthetic
appeal,
cost-effectiveness and availability, concrete is changing the face of
southern Africa's landscape.
Increasingly, cutting-edge architects and engineers are making concrete
their material of choice.
For
the Owner,
concrete offers both
aesthetic appeal
and cost effectiveness. Its
strength, durability and natural thermal mass result in buildings that
require
low maintenance, offer high durability and have high operating energy
efficiency.
| For
the Developer,
concrete offers a competitive
building solution based on first cost, long term economic benefits,
energy
efficiency, lower maintenance, and overall operating costs, as well as
opportunities for future reuse should the occupancy of the building
change. |
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For
the Designer,
concrete offers a dramatic range
of
colours, finishes and unlimited design possibilities, difficult to
match in
other materials. At the same time, a
structure is created that provides superior environmental and energy
performance. Designs that take advantage
of the thermal mass and structural integrity of concrete have resulted
in many
award-winning projects throughout the world. |
For the Country,
concrete is a low impact,
environmental
material and is the cornerstone for building construction and
infrastructure
that can put our society on the road to a sustainable future.
Specifics:
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Design Flexibility - concrete can be moulded into any shape by using appropriate
formwork. This capability can be used to
provide tailor-made design solutions to specific problems and also
aesthetically pleasing finishes which often eliminate the need for
further
fixings, e.g. false ceilings.
Due to its valued load-bearing properties, concrete allows for longer
floor spans with fewer columns to plan around.
This offers flexibility in architectural layout and even more usable
space. Increasingly, concrete is setting
the standard for space planning and utility infrastructure.
Thin concrete floor structures facilitate the use of raised floor
systems. Raised floors are ideal for
Intelligent Building Construction where the wiring is run in the space
below. Where flexibility and increased
wiring are common demands in new construction, concrete fits the bill.
Concrete is readily available from many locations across southern
Africa. A concrete
structure can be well underway before final plans are complete.
Earlier start-up means better cash flow for
owners and developers. As requests for changes are not uncommon
in any construction project,
the design flexibility of concrete allows the contractor to accommodate
design
changes after the construction process has begun.
Specification
Variety - concrete can be manufactured to an enormous range of specifications
to suit a wide variety of applications.
This can be achieved by using different mix designs or by the addition
of different materials.
A major advantage of concrete construction for engineered
structures is
the material’s properties of density and mass.
Lateral stiffness, or resistance to horizontal movement, make concrete
the product of choice when constructing in areas where high winds or
seismic
conditions are considerations. This
lateral stiffness also means that occupants of concrete towers are less
able to
experience building motion.
Durability -
concrete is one of the most durable materials on earth. Well
designed, well placed concrete offers
exceptional durability and long life in any structure. Concrete
structures built over 100 years ago
(even some as long as the Roman times)
are still in active service today. Such extended life span conserves
resources
by reducing maintenance and the need for reconstruction.
Aesthetic
Appeal - the aesthetic potential of concrete can be
exploited through a
variety of finishes. Exposed aggregate,
and off-shutter, are two broad categories of decorative surface
finishes. These techniques, combined with coloured
aggregates, imagination and various other methods, form the basis of
the
aesthetic expression in concrete structures.
With concrete cladding panels, a great range
of finishes and textures
are available. Precast panels are
extremely durable, weather resistant, offer superior air tightness,
increased
sound attenuation and thermal properties and are inherently fire
resistant. Concrete cladding permits
fast enclosure of the structure, allowing other trades to start sooner,
cutting
construction time, and reducing wall thickness to maximize rentable
space.
As natural stone becomes inaccessible or the cost prohibitive, concrete
is a natural alternative for recreating traditional finishes in a cost
effective way. Besides being widely
available and less expensive than quarried stone, cement-based cultured
stone
is easier to match and install. This
makes it popular even in places where quantities of quarried stone are
available.
Limited only by one’s imagination, the breadth of colours and textured
finishes available in concrete today is amazing. Mixing and
matching colours and textures
provides a spectrum of design possibilities.
Energy
Efficiency - the majority of concrete is produced locally,
minimizing fuel
requirements for handling and transportation.
Once in place, concrete offers significant energy savings over the
lifetime of the structure.
The energy efficiency of a structure is a major consideration in the
life
cycle cost analysis. Concrete
construction minimizes the overall building height. This shortens
vertical runs of mechanical and
electrical systems and reduces the exterior surface area to be enclosed
and
insulated.
The mass of a concrete structure makes it a significant thermal
reservoir with the ability to store large amounts of energy. In
the heating months, concrete walls and
floors absorb the interior heat during the day, then radiate warmth
back into
the space at night. The same principle
holds true for cooling. This thermal
inertia allows concrete to help maintain a relatively steady interior
temperature.
By storing and releasing the energy needed for heating or
cooling,
concrete delivers year-round energy-efficient buildings reducing peak
energy
demands and the size of HVAC equipment required.
Sound
Insulation -containing sound within the walls of a structure is critical in
today’s highly competitive environment.
Should tenant requirements include sound transmission control, the
natural mass of concrete floor and wall systems provides both
acoustical resistance
and vibration control.
Fire
Resistance - concrete is almost unique in being an
inexpensive, readily available
building material which is intrinsically fire resistant, needing no
additional
application of fire protection, and at the same time having structural
and
aesthetic qualities.
Light
reflectance – the light colour of concrete provides a safer
environment and also
enables lighting requirements to be reduced, both internally and
externally.
Faster
Construction - concrete provides faster construction which
means reduced carrying
costs and faster revenue generation.
This facilitates more timely pay back of financing charges and faster
revenue generation for the developer/owner.
Cost effectiveness- due to its
longevity and ease of construction, concrete is often the
most economical choice for engineered structures. Load-bearing
concrete exterior walls serve
not only to enclose the buildings, but to carry roof and wind loads –
eliminating
the need to erect separate cladding and structural systems.
Shallower floor systems are an important
structural advantage of
concrete. On average, the construction
of concrete buildings will allow one additional floor to be created for
each 10
stories of traditional building height, resulting in more rentable
space for
buildings of similar size. When faced
with height restrictions, concrete construction is a key consideration
and
could represent initial construction cost savings and additional income
generation.
Precast/prestressed concrete can help
reduce construction time and
on-site labour costs by taking advantage of pre-fabrication of standard
and
custom structure segments. Advanced
construction techniques such as “flying formwork systems”, increase the
speed
of floor construction. As a concrete
frame progresses upward, workers on the completed floors below can
proceed with
interior partitions, exterior finishing, electrical, mechanical and
plumbing systems.
Re-use - concrete is
an inert material that is easily recyclable.
Old concrete that has reached the end of its service life can be reused
as aggregate for new concrete mixtures.
The addition of industrial by-products such as fly ash, silica fume and
blast furnace slag enhance the various performance properties of
concrete,
whilst incorporating waste materials that would otherwise be deposited
in
landfill sites.
CONCRETE – CAN YOU AFFORD TO BE
WITHOUT IT?
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