Shuttering materials are important in civil engineering

5.  Introduction
Formwork is the term given to either temporary or
permanent molds into which concrete or similar
materials are poured. In the context of concrete
construction, the falsework supports the shuttering
moulds.
The construction of formwork takes time and
involves expenditure upto 20 to 25% of the cost of the
structure or even more. Design of these temporary
structures are made to economic expenditure. The
operation of removing the formwork is known as
stripping. Stripped formwork can be reused. Reusable
forms are known as panel forms and non-usable are
called stationary forms.
Materials used for the construction of concrete
formwork range from traditional materials such as
Timber, steel, aluminum, and plywood to
nontraditional materials such as fiberglass. The
systems used can be a combination of two materials.
Wood products are the most widely used material for
formwork. The objective of this section is to introduce
Timber as an important material for formwork.

7.  Timber :
Commonly used by the construction industry in
the formation of shuttering for casting concrete
on site. Often used with plywood and OSB board.
The timber used for this type of work is usually
lower grade carcasing timber with a planed sawn
edge (PSE).
Timber used for shuttering for exposed concrete
work should have smooth and even surface on all
faces which come in contact with concrete.
• Normal sizes of members for timber
formwork:

10. Bamboo :
Bamboo as a building material has high
compressive strength and low weight has been one
of the most used building material as support for
concrete, especially in those locations where it is
found in abundance.
Bamboo as a building material is conventionally
associated with the region of Southeast Asia and
South America where climate is best suitable for
its cultivation. In many of the nations, bamboo is
used to hold up suspension bridges or simply
make places of dwelling.

13.  Steel :
The major advantages of steel sections
in formwork are the ability of steel to
form longer spans and its indefinite
potential for reuse when handled with
reasonable care. Steel sections are used
in the fabrication of different formwork
components, namely:
(1) Steel panel forms.
(2) Horizontal and vertical shores.
(3) Steel pan and dome components
used for joist and waffle slabs.
(4) Steel pipes for formwork bracing.

14. Other heavy forms and formwork are also
made of steel, such as bridge formwork.
Steel is used for formwork when other
materials are impossible to use because of
their low strength. Steel forms are typically
patented, and allowable loads are generally
published by the manufacturers.

16. Aluminum stems from have lighted weight
which reduces handling costs and offsets its
higher initial material cost. When compared
to steel panels, aluminum panels used for
ganged forms weight approximately 50%
less. The major problem with aluminum
forms is corrosion: Pure aluminum is
attacked chemically by wet concrete.
Aluminum alloys have proven to be very
successful in resisting corrosion. Support
trusses fabricated with aluminum alloys
have been effectively used for flying forms.
These forms are lightweight and allow large
lengths of deck forms to be moved easily.
Cast aluminum alloy molds have also been
used successfully to form ornamental
concrete products.
 Aluminum:

17. Aluminum wall forms have also been used
to produce textures on the surfaces of
concrete walls. Because the strength of
aluminum in handling, tension, and
compression is less than the strength of
steel, it is necessary to use larger sections
when forms are made of aluminum.
Because wet concrete can chemically
attack aluminum, it is desirable to use
aluminum alloys in resisting corrosion
from the concrete.

19.  Glass fibre reinforced polymer
Glass fibres are basically made by mixing silica
sand, limestone, folic acid and other minor
ingredients. The mix is heated until it melts at
about 1260°C. The molten glass is then allowed to
flow through fine holes in a platinum plate. The
glass strands are cooled, gathered and wound. The
fibres are drawn to increase the directional
strength. The fibres are then woven into various
forms for use in composites.
Glass fiber reinforced polymer sheet
Based on an aluminium lime borosilicate
composition glass produced fibres are considered
the predominant reinforcement for polymer matrix
composites due to their high electrical insulating
properties, low susceptibility to moisture and high
mechanical properties. Glass is generally a good
impact resistant fibre but weighs more than carbon
or aramid. Glass fibres have excellent
characteristics equal to or better than steel in
certain forms.