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except to expedite the placing of embcddcd materials. The intcl-vx!’
19 IS:457-1957 between two lifts shall also be maintained
as possible, and
the difference of elevation between any two adjacent blocks shall not be
more than 900 cm ( or 30 ft ) and not less than 150 cm ( or 5 rr 1. A
period of 5 days for 150 cm ( or 5 ft ) of concrete laid shall be allowed
before the next pour unless heat dissipation methods warrant otherwisti.
4.10.8 Placing ‘Plums ’ in
be used, they shall be washed
before being embedded in the
30 cm ( or 12 in ) to an exposed
an adjacent stone.
stone shall be laid and carefully
forms or adjacent masonry and
ness of unnecessary
seams occur Concrete - Where plums are permitted
and all dripping
surface water removed
No stone shall be closer than
surface nor nearer than 15 cm ( or 6 in ) to
shall not be dropped in place, but each
embedded so as.to avoid any injury to the
in such a manner that no planes of weakin the structure. 4.10.9 Satye Blocks-In
placing concrete in large blocks, the work
shall in general proceed from the low side to the high side so that the working face is never excessively steep nor long.
However, for construction
joints in dams, the work shall proceed from the high side to the low side so
as to maintain
an upward slope in the downstream
direction, unless construction
joints are otherwise shown on the drawings.
Under no condition shall the slope be so steep as to cause the concrete to flow without
The concrete shall be deposited as
working, or to cause any segregation.
nearly ‘as practicable
in final position and shall not be piled up in large
masses at any point and then pushed, shovelled, or vibrated into space
for kJtlg distances.
It shall be brought up evenly around all large openings,
conduits, or embedded metal so as to minimize unequal pressure and avoid
For large blocks of concrete in dams and other massive
the sequence and rate of casting successive lifts and adjacent
blocks shall be such as to faciiitate the dissipation of the heat of hydration. 4.10.10 Iirjcctd
Coxcyete - A!1 concrete
rejected and removed from ti.c Gt.t: of operations,
fresh concrctt:; where concrete has rllready been
it shall be dug out and removed from the forms.
proper placement or in a such condition that it
pacted, shall be removed.
4.11 inferior quality shall be
if possible, before placing
placed, if found inferior,
Any batch, too stiff for
cannot be properly com- Compacting 4.11.1 .~fethnrl - Concrete shall 1~. thoroughly
of suitable tools during and imrncrliately
sIrall 1,~ worked around a11 I-cinforctrment,
fixtures, and into
the* corI?c’rs of the forms.
Every precaution shall’be taken to keep the reinforcctmetlt
metal in proper position
and to prevent
distortion. IS : 457 - 1957
shall include rodding, spading, tamping,
vibrating, treading, and such other operation...
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This document was uploaded on 10/01/2013.
- Fall '13