30
gardless of which construction method is em-
ployed. The primary difference between the two
methods is that with the antifreeze method the
shelter would not have to be heated after the
25
work stopped. In this case, the weather was mild
enough that the antifreeze side of the shelter did
not have to be heated for the comfort of the masons.
The workers were able to stay warm just by wear-
20
ing jackets but no gloves. There was no signifi-
cant difference in the production rate between the
two walls. Other labor and materials are consid-
ered common to both construction methods.
15
A heater produced 34,000 Btu/hr for each day
it was in operation. Two heaters were used. A
commonly used heat source on construction sites
is liquid propane. At
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.94/gal and 91,000 Btu/
5
gal, the cost to keep the conventional mortar
above freezing was about /day. On the other
hand, based on costs for other admixtures sold on
the market today, the antifreeze admixture is esti-
0
Control Site
mated to cost about .00 for the total amount of
KC1 Site
admixture used on this project. Since the mortar
Figure 22. Strength of mortar cylinders
only had to be heated for 1 day, the antifreeze ad-
cast during construction.
mixture produced no cost saving--it cost as
much as the heat. Keep in mind that the average
daily outdoor temperature was roughly 3C
antifreeze mortar, cured in the unheated side of
(37F). Colder temperatures would increase heat-
the shelter for 7 days, is as strong as the conven-
ing demand. The saving in this case, however, is
tional mortar.
that no fuel had to be burned to protect the anti-
freeze mortar.
Efflorescence
Although the cost comparison and productiv-
Efflorescence is of concern whenever anything
ity of the two walls in this demonstration did not
is added to the mortar, and it appears to occur
yield significant differences, antifreeze admix-