RCC Slab Casting – Work Procedure
Reinforcement
It shall be as per BBS prepared according to approved drawing. The
R/F shifting and binding shall be started as soon as shuttering is
completed. R/F binding shall continue as formwork and shuttering
work is progresses.
Concreting
Construction joint
The construction joint shall be pre decided and fixed prior to start of
the concreting. It is planned to have two construction joints for main
building as decided. In case of major break down of the Batching
plant, the additional Construction joint may be left. The location of
the construction joint shall be at the one-third span. Construction
joint shall be straight and have profile of ‘L’shape so that successive
layer of concrete shall be perfectly bonded with previous laid layer.
Preparation of construction joint shall include roughening, removing
all laitance adhering to the joint and application of thick slurry before
start of the new concrete.
Production and placement of concrete.
Stock of material shall be sufficient to start the concrete. It shall be
ensured by stores/purchase dept that concreting is not stopped on
account of materials.
All plant and machinery are checked and made in working conditions.
Concrete of grade M-25 shall be produced from our batching plant
and directly pumped to the location of concrete placement through
the pipeline. The pouring sequence shall be from grid A towards
construction joint. Since the grade of concrete for column is M-40
and surrounding concrete is M-25, sufficient offset around column
shall be casted with M-40.The offset dimensions shall be provided by
PMC.
Proper walkways/platforms shall be arranged so that the supports of
the pipeline and manpower are not directly stand on reinforcement.
Sufficient carpenters along with supervisor shall inspect the behavior
of supports below the slab during the casting. Extra Props shall be
stocked below slab to provide additional supports in case of any
failure of supports.
Curing
The curing shall be started immediately after thumb set of the
concrete laid. Hessian clothe /Plastic shall be covered over the set
concrete to reduce moisture evaporation from the concrete during
hardening and thus to minimize shrinkage crazy cracks. These
cracks are inheriting property of the concrete specially appears
during casting of flat surfaces.
Final curing shall be done by ponding and stacking water for
minimum period of 7 days.
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