Page
Section
Para.
Recommendation
6
Masonry mortar frozen after it has cured 8 hours is able to
resist a single freezing cycle. When moisture transfer
between the mortar and the surrounding environment is
completely prohibited, which is conservative compared
with field conditions, the amount of freezable water in
fresh mortar decreases as the mortar ages. Some of the
water chemically combines with cement during hydration,
and some becomes entrapped within the extremely fine
pore structure of the hardening cement gel. This water is
practically unfreezable. By an age of 8 hours, the freezable
water content diminishes to where one cycle of freezing
and thawing will not be disruptive.
Although a few ... conclusions. Mortar of sufficient
7
maturity and exposed to the cold at an early age can
attain more late-age strength than their warm-cured
counterparts. For example, mortar that is cured for 12 to
16 hours at or above 40F (5C), then exposed to sub-0C
temperatures for about 12 hours, and then returned to 40F
(5C) or above can attain about 10% more late-age
strength than mortar that is continuously cured at 70F
(20C).
Summary
8
The consensus of the Council regarding the performance
of masonry at low temperature is that masonry should be
constructed in such a manner that it will develop sufficient
strength maturity and or that the mortar will lose suffi-
cient water to prevent freezing. Further, all masonry frozen
dried during the early periods after construction should be
moistened either naturally or artificially to reactivate
ensure continuing the cement hydration process, which in
turn will promote further strength development of the
masonry.
Materials
Masonry Units
1
All masonry units ... construction. No change or ... ma-
sonry. Low absorption units ... freezing. The effect of the ...
if freezing occurs after the moisture within the mortar has
been decreased sufficiently low or the mortar has attained
sufficient maturity to prevent expansion on freezing. Units
with ... instances. Units with ... freezing.
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Admixtures
Antifreeze
1
Most of the ... misidentified. They are ... depressants.
Antifreeze admixtures are chemical compounds that both
depress the freezing point of water and accelerate strength
gain of mortar at low temperatures. Some actual anti-
freeze admixtures freeze-point depressants are available ...
alcohol. If used in quantities ... rapidly. Since antifreeze ...
recommended.
Recent work1 has shown that antifreeze admixtures can
11
2
protect mortar from freezing when the internal tempera-
ture of the mortar is below 0C with no detrimental side-
effects to the mortar. The main drawback is that there are
no commercially available antifreeze admixtures today.
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