The surfaces of [_____] shall be given a grout-cleaned finish as described,
as approved by the Contracting Officer and after all required curing,
cleaning, and repairs have been completed. Surfaces to be grout-cleaned
shall be moist cured for the required period of time before application of
the grout-cleaned finish. Grout-cleaning shall be delayed until near the
end of construction on all surfaces not to be painted in order to achieve
uniformity of appearance and reduce the chance of discoloring caused by
subsequent construction operations. The temperature of the air adjacent to
the surface shall be not less than 5 degrees C 40 degrees F for 24 hours
prior to and 72 hours following the application of the finish. The finish
for any area shall be completed in the same day, and the limits of a
finished area shall be made at natural breaks in the finished surface. The
surface to receive grout-cleaned finish shall be thoroughly wetted to
prevent absorption of water from the grout but shall have no free water
present. The surface shall then be coated with grout. The grout shall be
applied as soon as the surface of the concrete approaches surface dryness
and shall be vigorously and thoroughly rubbed over the area with clean
burlap pads, cork floats or stones, so as to fill all voids. The grout
shall be composed of one part portland cement as used on the project, to
two parts by volume of well-graded sand passing a 600-m (No. 30) sieve
mixed with water to the consistency of thick paint. White portland cement
shall be used for all or part of the cement as approved by the Contracting
Officer to give the desired finish color. The applied coating shall be
uniform, completely filling all pits, air bubbles, and surface voids.
While the grout is still plastic, remove all excess grout by working the
surface with a rubber float, burlap pad, or other means. Then, after the
surface whitens from drying (about 30 minutes at normal temperature) rub
vigorously with clean burlap pads. Immediately after rubbing is completed,
the finished surface shall be continuously moist cured for 72 hours.
Burlap pads used for this operation shall be burlap stretched tightly
around a board to prevent dishing the mortar in the voids.]
3.4.2.2
[Textured Finish
This type of finish shall be applied where specified to conform to details
shown in the drawings by use of approved textured form liners. Liner
panels shall be secured in the forms by methods recommended by the
manufacturer but not by methods that will permit impressions of nail heads,
screw heads, washers, or the like to be imparted to the surface of the
concrete. Edges of textured panels shall be sealed to each other to
prevent grout leakage. The sealant used shall be nonstaining to the
surface. The finish shall be similar to and shall closely match the finish
on the sample panel.]
3.4.2.3
[Exposed Coarse-Aggregate Finish
Coarse aggregate shall be exposed by a method preapproved by the
Contracting Officer. The finish shall be similar to and shall closely
match the finish on the sample panel.]
3.4.2.4
[Sand-Blast Finish
The concrete surface shall be blasted to obtain a [brush] [light] [medium]
[heavy] uniform finish prepared in accordance with the descriptive
photographs in ACI 303R. The finish shall be similar to and shall closely
match the finish on the sample panel.]
SECTION 03301A
Page 39
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