APPENDIX C: PROPOSED CHANGES TO USACE GUIDANCE
Example document to be changed: CEGS 03300 (September 1995)
Section: 2.3 Chemical Admixtures
Change #1
Insert "Antifreeze Admixtures" as number 2.3.7 using the text below, and
renumber the section on "Other Chemical Admixtures" to be number 2.3.8.
Suggested Insertion
Antifreeze admixtures
An antifreeze admixture shall be able to promote the strength of concrete cured
at 5C 1C to reach a minimum seven-day strength of 40% of the strength of an
equivalent admixture-free concrete cured at 20C at the same age, and a minimum
14-day strength of 60% of the strength of an equivalent admixture-free concrete
cured at 20C at the same age. The test specimens shall be standard cylinders 7.6 cm
in diameter or larger. The concrete shall be mixed and cylinders cast at room
temperature (about 20C). The specimens to be cured at 5C shall be brought into
the cold chamber no more than 40 minutes after water has been added to the cement
during mixing. The cold chamber shall be able to cool the center of mass of the
cylinders to 0C or lower within three hours, and to 4C within eight hours. The
temperature of the cylinders shall be measured with embedded thermocouples on
replicate specimens. On the day of the compressive strength test, the cylinders shall
be moved from the cold room to a warm room at about 20C. The temperature at the
cylinders' center of mass shall be allowed to reach 5C before being compression
tested. The cylinders shall be compression tested within one hour of reaching 5C.
Except for the strength requirements, the admixture shall meet the physical
requirements set forth in ASTM C 494 for an admixture Type C.
For cast-in-place concrete, the admixture shall not contain more than 2% of
calcium chloride by weight of cement. For prestressed concrete, the admixture shall
not contain any chlorides, except in trace amounts.
The admixture may add alkalis only to the extent that the total mixture alkali
content does not exceed 0.6% by weight of cement.
Change #2
Rewrite section 3.8.3, "Cold Weather Requirements," as follows:
There are two possible protection measures that can be used when the ambient
temperature drops below 0C. The first measure entails thermal protection and the
second method entails chemical protection. Whichever method is chosen, it must be
approved by the Contracting Officer.
Thermal Protection may be chosen if freezing temperatures are anticipated before
the expiration of the specified curing period. The ambient temperature of the air
where concrete is to be placed and the temperature of surfaces to receive concrete
shall not be less than 5C (40F). Heating of the mixing water or aggre
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