(1) Transporting and Handling:-
After mixing, concrete shall be transported to the
formwork asrapidlyas possiblebymethods whichwill
prevent the segregation Of Jossof any of the ingredients
or ingress of foreign matter or water and maintaining
(he required workability
13.1.1 During hoi Of cold weather. concrete shall be
transportedindeep containers. Othersuitable methods
to reduce the loss of water hy evaporation in hot
weather and heat loss in cold weather may also be
adopted
(2) Placing:-
TIleconcrete shall he depositedas nearlyas practicable
in its final position to avoid rehandling. The concrete
shall he placed and compacted hefore initial setting of
concrete commences and should not be subsequently
disturbed. Methods of placing should be such as
to preclude scgreg.rtion. Care should be taken to
avoid displacement of reinforcement or movement
of Iorrnwork . As a general guidance, the maxi ...
mum permissible free fall of concrete may be taken
as 1.5 Ill.
(3) COmpaction:-
Concrete should he thoroughly compacted and fully
worked around the reinforcement, around embedded
fixtures and intocorners of the fonnwork.
13.3.1 Concrete shall be compacted using mechanical
vibrators complying with IS 2505, IS 2506. IS 2514
and IS 4656. Over vibration and under vibration of
concreteare harmful and should beavoided. Vibration
of very wet mixesshould also he avoided.
Whenever vibration has to be applied externally, the
design of formwork and the disposition of vibrators
shouldreceivespecialconsiderationto ensure efficient
compaction and to avoid surface blemishes.
(4) Curing:-
Curing isthe process of preventing the Jossof moisture
from the concrete whilst maintaining a satisfactory
temperature regime. The prevention of moisture loss
from the concrete is panicularly importantifthe watercement ratio IS low, ifthe cement has a high rate of
strength development, if the concrete contains
granulated blast furnace slag or pulverised fuel ash.
TIlecuringregimeshould alsoprevent the. development
of high temperature gradients within the concrete.
The rate of strength development at early ages of
concrete made with supersulphated cement is
significantly reduced at" lower temperatures.
Supersulphated cement concrete is seriously affected
by inadequate curing and the surface has to be kept
moist for at least seven days.
13.5.1 Moist Curing
Exposed surfaces of concrete shall be kept
continuously in a damp Of wet condition by pending
or by covering with a layer of sacking, canvas, hessian
or similar materials and kept constantly wet for at least
seven days from the date of placing concrete in case
After mixing, concrete shall be transported to the
formwork asrapidlyas possiblebymethods whichwill
prevent the segregation Of Jossof any of the ingredients
or ingress of foreign matter or water and maintaining
(he required workability
13.1.1 During hoi Of cold weather. concrete shall be
transportedindeep containers. Othersuitable methods
to reduce the loss of water hy evaporation in hot
weather and heat loss in cold weather may also be
adopted
(2) Placing:-
TIleconcrete shall he depositedas nearlyas practicable
in its final position to avoid rehandling. The concrete
shall he placed and compacted hefore initial setting of
concrete commences and should not be subsequently
disturbed. Methods of placing should be such as
to preclude scgreg.rtion. Care should be taken to
avoid displacement of reinforcement or movement
of Iorrnwork . As a general guidance, the maxi ...
mum permissible free fall of concrete may be taken
as 1.5 Ill.
(3) COmpaction:-
Concrete should he thoroughly compacted and fully
worked around the reinforcement, around embedded
fixtures and intocorners of the fonnwork.
13.3.1 Concrete shall be compacted using mechanical
vibrators complying with IS 2505, IS 2506. IS 2514
and IS 4656. Over vibration and under vibration of
concreteare harmful and should beavoided. Vibration
of very wet mixesshould also he avoided.
Whenever vibration has to be applied externally, the
design of formwork and the disposition of vibrators
shouldreceivespecialconsiderationto ensure efficient
compaction and to avoid surface blemishes.
(4) Curing:-
Curing isthe process of preventing the Jossof moisture
from the concrete whilst maintaining a satisfactory
temperature regime. The prevention of moisture loss
from the concrete is panicularly importantifthe watercement ratio IS low, ifthe cement has a high rate of
strength development, if the concrete contains
granulated blast furnace slag or pulverised fuel ash.
TIlecuringregimeshould alsoprevent the. development
of high temperature gradients within the concrete.
The rate of strength development at early ages of
concrete made with supersulphated cement is
significantly reduced at" lower temperatures.
Supersulphated cement concrete is seriously affected
by inadequate curing and the surface has to be kept
moist for at least seven days.
13.5.1 Moist Curing
Exposed surfaces of concrete shall be kept
continuously in a damp Of wet condition by pending
or by covering with a layer of sacking, canvas, hessian
or similar materials and kept constantly wet for at least
seven days from the date of placing concrete in case
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