Formwork

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Formwork
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Formwork
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Formwork

• The cost of formwork can be 1/3 to 2/3 of the
  total cost of a concrete structure.
• Requirements of formwork
• tolerances should be within specified limits.
• sufficiently strong to carry construction loads
  and side pressures from fresh concrete
• rigid enough to prevent movement during
  placement.
• Joints should be tight to prevent leakage of
  mortar.
• Should provide the desired surface finish.
• Designed to be simply erected and dismantled
  specially if it is to be re-used.
• Formwork should not be stripped before concrete
  has developed adequate strength.
• Vertical forms can generally be stripped before
  beam or soffit forms.

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Concrete handling

• Concrete is usually transported to its point of
  placement in agitating or non agitating trucks
• Concrete should be transported without
  significantly altering its desired properties
  such as slump, w/c ratio, air content and
  homogeneity.
• Loss of workability during warm weather may be
  minimized by
• expediting delivery and placement
• adding crushed ice to mixing water or cooling the
  water by refrigeration.
• injecting liquid nitrogen into the mixer or
  agitator truck
• using a retarding admixture.

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Finishes

• It is usually economical for the structural
  material to provide the surface finish.
• Surface finish depends on materials used
• sawn timber
• new boards are sealed with form oil to to prevent
  absorption
• plastic coated plywood
• fibreglass
• used for difficult shapes and profiles
• gives a very smooth mirror finish
• High quality surface finishes are required if the
  surface is to be bush hammered or sandblasted for
  architectural reasons.
• Poor quality formwork causes
• Honeycombing, blowholes, misalignment, plastic
  cracking

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Finishes
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Finishing ConcretePower Screed

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Finishing ConcretePower Trowel

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Finishing ConcreteRide-on Power Trowel

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Finishing ConcreteSlip-form Curb Layer

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Finishing ConcreteConcrete Roads