rain or other weather shall be completely removed full depth, by full slab
width, to the nearest original joint, and replaced at the Contractor's
expense as specified in paragraph: REPAIR, REMOVAL AND REPLACEMENT OF NEWLY
CONSTRUCTED SLABS,
3.3.2
Paving in Hot Weather
**************************************************************************
NOTE: Additional information concerning hot weather
concreting may be obtained from ACI 305R. Do not
delete this paragraph or the next paragraphs dealing
with weather.
**************************************************************************
When the ambient temperature during paving is expected to exceed 32 degrees
C 90 degrees F, the concrete shall be properly placed and finished in
accordance with procedures previously submitted, approved, and as specified
herein. The concrete temperature at time of delivery to the forms shall
not exceed the temperature shown in the table below when measured in
accordance with ASTM C 1064/C 1064M. Cooling of the mixing water or
aggregates or placing in the cooler part of the day may be required to
obtain an adequate placing temperature. Steel forms and reinforcing shall
be cooled as needed to maintain steel temperatures below 49 degrees C 120
degrees F. Transporting and placing equipment shall be cooled or protected
if necessary to maintain proper concrete placing temperature. The finished
surfaces of the newly laid pavement shall be kept damp by applying a fog
spray (mist) with approved spraying equipment until the pavement is covered
by the curing medium.
Maximum Allowable Concrete Placing Temperature
Relative Humidity, Percent,
Maximum Allowable Concrete
During Time of Concrete Placement
Temperature in Degrees C
___________________________________
_________________________
Greater than 60
33
40-60
30
Less than 40
27
Maximum Allowable Concrete Placing Temperature
Relative Humidity, Percent,
Maximum Allowable Concrete
During Time of Concrete Placement
Temperature in Degrees F
___________________________________
_____________________________
Greater than 60
90
40-60
85
Less than 40
80
3.3.3
Prevention of Plastic Shrinkage Cracking
During weather with low humidity, and particularly with high temperature
and appreciable wind, the Contractor shall develop and institute measures
to prevent plastic shrinkage cracks from developing. If plastic shrinkage
cracking occurs, further placement of concrete shall be halted until
protective measures are in place to prevent further cracking. Periods of
high potential for plastic shrinkage cracking can be anticipated by use of
Fig. 2.1.5 of ACI 305R. In addition to the protective measures specified
in the previous paragraph, the concrete placement shall be further
SECTION 02753
Page 54
Previous Page
