Unformatted text preview: the prescribed lines, shall be removed and
replaced with dry-1)atching mortar.
Where bulges and abrupt irregularities protrude outside the reqnirecl limits and where it is required to
finish the surfaces with iinishes F2 and F3, the protrusions shall be reduced by bush-hammering and grinding so that the surfaces are brought
within the required limits. Drypack filling shalt he used for holes having
at le,ast one surface dimension not greater than the hole depth, for holes
left by removal of fasteners from the ends of ,form tie rods, for grout pipe
recesses, and for narrow slots cut for repair of cracks. Filling of holes
left by the removal of fasteners from the ends of the tie rods in surfaces
for which Fl finish is specified, shall not be required. Dry-patching mortar
shall consist of one part of cement to two parts of sand by volume, and
just enough water to hold the ingredients together.
The mortar shall be
placed in layers of 2.5 cm (or 1 in ) each layer thoroughly tamped, an?
the finishing layer shall bc smoothened to form the surface continuous with
26 IS : 457 - 1957
.the surface of the holes and shall be sound and free from shrinkage
All tilling shall be bonded rightly
hollow areas after the fillings have been cured and have dried.
to the Finiehea and Finishin@ 4.16.1 Concrete surfaces shall be tested where necessary to deter
mine whether surface irregularities are within the specified limits.
are classified as ‘ abrupt ’ oi *gradual ‘. Offsets caused
by displaced or misplaced form sheathing or lining or form sections, .or
by loose knots in forms or otherwise defective timber forms shall be considered as abrupt irregularities, and shall be tested by direct measurement.
All other irregularities shall be considered as gradual irregularities, and
tested by use of a template, con&sting of a straight edge or the equivalent
thereof for curved surfaces.
The length of the template shall be 150 cm
( or 5 ft ) for testing of formed surfaces and 300 cm ( or 10 ft ) for testing
of unformed surfaces.
4.16.2 Formed Surfaces - The finish
shall be of the following four classes: 4 ‘4 cl for formed concrete surfaces Finish Fl - Finish Fl shall apply to formed surfaces upon which
or against which backfill or concrete is to be placed.
require no treatment after removal of forms except removal and
repair of defective concrete and the specified curing.
of surface irregularities shall be done only for depressions which
when measured as described under 4.16.1 exceed 2.5 cm ( or 1 in ).
Finish F2 - Finish F2 shall apply to all permanently
formed surfaces for which finishes F3 and F4 arc not specified.
Surfaces for which finish F2 is specified will need no filling of pits
or sack rubbing and no grinding other than that needed for repair
of surface imperfections.
described under 4.16.1 shall not exceed 0.5 cm ( or t in ) for abrupt irr...
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This document was uploaded on 10/01/2013.
- Fall '13