the ambient temperature is below 4 degrees C (40 degrees F) 40 degrees F or
when concrete is likely to be subjected to freezing temperatures within 24
hours. Cover concrete and provide sufficient heat to maintain 10 degrees C
(50 degrees F) (5 degrees F) 50 degrees F minimum adjacent to both the
formwork and the structure while curing. Limit the rate of cooling to 3
degrees C (5 degrees F) 5 degrees F in any 1 hour and 10 degrees C (50
degrees F) 50 degrees F per 24 hours after heat application.
]3.6.6
Hot Weather
ACI 305R. Maintain required concrete temperature using Figure 2.1.5 in ACI
305R to prevent the evaporation rate from exceeding 1 kg per square meter
(0.2 pound of water per square foot) 0.2 pound of water per square foot of
exposed concrete per hour. Cool ingredients before mixing or use other
suitable means to control concrete temperature and prevent rapid drying of
newly placed concrete. Shade the fresh concrete as soon as possible after
placing. Start curing when the surface of the fresh concrete is
sufficiently hard to permit curing without damage. Provide water hoses,
pipes, spraying equipment, and water hauling equipment, where job site is
remote to water source, to maintain a moist concrete surface throughout the
curing period. Provide burlap cover or other suitable, permeable material
with fog spray or continuous wetting of the concrete when weather
conditions prevent the use of either liquid membrane curing compound or
impervious sheets. For vertical surfaces, protect forms from direct
sunlight and add water to top of structure once concrete is set.
3.7
SURFACE FINISHES EXCEPT FLOOR, SLAB, AND PAVEMENT FINISHES
3.7.1
Defects
Repair formed surfaces by removing minor honeycombs, pits greater than 600
square mm (1 square inch) 1 square inch surface area or 6 mm (0.25 inch)
0.25 inchmaximum depth, or otherwise defective areas. Provide edges
perpendicular to the surface and patch with nonshrink grout. Patch tie
holes and defects when the forms are removed. Concrete with extensive
honeycomb including exposed steel reinforcement, cold joints, entrapped
debris, separated aggregate, or other defects which affect the
serviceability or structural strength will be rejected, unless correction
of defects is approved. Obtain approval of corrective action prior to
repair. The surface of the concrete shall not vary more than the allowable
tolerances of ACI 347R. Exposed surfaces shall be uniform in appearance
and finished to a smooth form finish unless otherwise specified.
3.7.2
Not Against Forms (Top of Walls)
Surfaces not otherwise specified shall be finished with wood floats to even
surfaces. Finish shall match adjacent finishes.
3.7.3
Formed Surfaces
3.7.3.1
Tolerances
ACI 117 and as indicated.
3.7.3.2
As-Cast Rough Form
Provide for surfaces not exposed to public view. Patch this holes and
defects and level abrupt irregularities. Remove or rub off fins and other
projections exceeding 6 mm (0.25 inch) 0.25 inch in height.
SECTION 03300N
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