Unformatted text preview: the course of construction.
The length of time,
the forms would remain in place, shall be decided with reference to weather
conditions, slope and position of the structure or structural member and
the nature and amount of dead and live loads.
55.1 In no case should forms be removed until there is assurance
that their removal is possible without chipping, spalling or defacing the
concrete surface. Furthermore, heavy loads shah not be permitted until
after the concrete has reached its designed strength.
All forms shall be
entirely removed from a lift to permit inspection before the forms for
the next lift are set.
31 IS : 457 - 1957
6. CONSTRUCTION JOINTS 6.1 Location of Joints - The location and type of all construction joints
shall be shown on the drawings, and no other joints or type of joints shall
be built unless specifically approved by the competent authority.
Joints - The stipulations of 4.10.5 for cleaning masonry
joints and bonding ne\v concrete to old shall apply to all horizontal construction
or dowels for resistance
to shear shall be
At least 2 hours
carefully formed and placed as shown on the drawings.
after depositing concrete in columns or supporting walls beAll joints shall be finished
fore placing the concrete in the floor system.
to present a sharp level, straight line in the exposed face.
essentially the same care as other exposed surfaces.
the adjoining sections of masonry shall be complete,
tailed on the drawings. 6.4 Water-tight shall be built with
The break between
unless otherwise de- Joints 6.4.1 Whcrc horizontal construction
joints are subject to water pressure, special care shall be taken to bond the next lift of concrete.
consistency of the concrete shall be carefully controlled so as to avoid sand
and after compaction no free water shall show anywhere along
The surface shall be carefully cured as specified under 4.15
and shall IX protcctcd from mechauical injury.
Before placing the next
lift, the joint shall hc cleaned and prel)arcd as sljccified under 4.10.5.
6.4.2 In casting vertical joints reqnir’ed to be water-tight, care shall be
taken not to injure or displace the grout pipine \vatcr stops, or seals called
for on tile tlrawirlgs.
Joints -- Vv’hcrcvcr plncirlg is interrnptctl
the concrete to take its final set. the working face shall be so formed
lini~lrctl as to provide union with subscqucnt
\\,ork equal to that spccifor regular construction joints. 7. TESTS
7.1 Field Tests - Field tests of all concrete being placed shall be regularly conducted.
In general, as a reliable indication of other physical
properties, the quality of the concrete being produced shall be judged by a
comparison of the compressive strengths developed within a given period.
32 IS : 457 - 1957
7.2 Laboratory Test.- A properly equipped testing laboratory to control the quality of the co...
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- Fall '13
- Bombay, Concrete Association, Concrete Section31 Committee, Concrete Subcommittee