replacement concrete in accordance with paragraph MATERIAL AND PROCEDURE
FOR REPAIRS.
3.4.3.3
Class D Finish
Surfaces listed in Section 03100A STRUCTURAL CONCRETE FORMWORK and as shown
to have class D finish shall have surface defects repaired as follows:
defective areas, voids, and honeycombs greater than 30 000 square mm 48
square inches in area or more than 50 mm 2 inches deep shall be defined by
13 mm 1/2 inch deep dovetailed saw cuts in a rectangular pattern, the
defective concrete removed by chipping and the void repaired with
replacement concrete. The prepared area shall be brush-coated with an
epoxy resin meeting the requirements of paragraph EPOXY RESIN, a latex
bonding agent meeting the requirements of paragraph LATEX BONDING COMPOUND,
or a neat cement grout after dampening the area with water. The void shall
be filled with replacement concrete in accordance with paragraph MATERIAL
AND PROCEDURE FOR REPAIRS.
3.4.3.4
Material and Procedure for Repairs
The cement used in the dry-packed mortar or replacement concrete shall be a
blend of the cement used for production of project concrete and white
portland cement properly proportioned so that the final color of the mortar
or concrete will match adjacent concrete. Trial batches shall be used to
determine the proportions required to match colors. Dry-packed mortar
shall consist of one part cement to two and one-half parts fine aggregate.
The fine aggregate shall be that used for production of project concrete.
The mortar shall be remixed over a period of at least 30 minutes without
addition of water until it obtains the stiffest consistency that will
permit placing. Mortar shall be thoroughly compacted into the prepared
void by tamping, rodding, ramming, etc. and struck off to match adjacent
concrete. Replacement concrete shall be produced using project materials
and shall be proportioned by the Contracting Officer. It shall be
thoroughly compacted into the prepared void by internal vibration, tamping,
rodding, ramming, etc. and shall be struck off and finished to match
adjacent concrete. Forms shall be used to confine the concrete. If an
expanding agent is used in the repair concrete, the repair shall be
thoroughly confined on all sides including the top surface. Metal tools
shall not be used to finish permanently exposed surfaces. The repaired
areas shall be cured for 7 days. The temperature of the in situ concrete,
adjacent air, and replacement mortar or concrete shall be above 5 degrees C
40 degrees F during placement, finishing, and curing. Other methods and
materials for repair may be used only when approved in writing by the
Contracting Officer. Repairs of the so called "plaster-type" will not be
permitted.
3.5
CURING AND PROTECTION
3.5.1
Duration
The length of the curing period shall be determined by the type of
cementitious material, as specified below. Concrete shall be cured by an
approved method.
[Type III portland cement _______________________________
3 days]
[Portland cement when accelerator is used to achieve
high early strength, except when fly-ash or
GGBF slag is used ___________________________________
3 days]
SECTION 03301A
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