ing with conventional methods according to ex-
concrete mix. This may pose a problem if reactive
isting specifications, and the lack of standards for
siliceous aggregates are used. Alkali-silica reac-
the new low-temperature admixtures. Therefore,
tion is not an issue with calcareous aggregates
it becomes a somewhat negative cycle: users wait
such as limestone. Natural sand is made of sili-
for commercially available admixtures and stan-
ceous mineral, but it is chemically inert, and there-
dards; admixture manufactures wait for the mar-
fore does not react with alkalis. Consequently, KC1
ket to grow.
should be safe for use in mortar and grouts that
The U.S. Army Corps of Engineers is the larg-
have only natural sand as aggregate. For combat
est civil engineering organization in the world.
engineering applications and for emergency con-
The Corps has provided leadership in many areas
struction, where the short-term goals are predomi-
of civil engineering technology. The antifreeze ad-
nant, KC1 would be recommended.
mixtures technology presents both a challenge and
Much work is needed in promoting standards
an opportunity for the Corps to lead the way by
for antifreeze admixtures to encourage their de-
developing the needed standards for working in
mand. Admixture manufacturers must consider
the winter with concrete that is not heated. A pro-
many factors in assessing the convenience of
posal for changes to a Corps guide specification is
launching a new admixture into the market.
included in Appendix C.
Some of these factors are beyond technical con-
trol. Tort liability concerns discourage private
construction industry in the United States from
trying new materials for which industry stan-
RECOMMENDATIONS
dards are not available. Industry standards are
Daraset and PolarSet are two commercial ad-
difficult to set without extensive product appli-
mixtures that were evaluated during this project.
cation. Admixture producers would like to have
Both of these are excellent admixtures for the range
the market demand before investing in a new
of temperatures for which they are specified. Nei-
product. The U.S. Army Corps of Engineers may
ther of these admixtures met the minimum
be a catalyst for the implementation of this new
strength requirements set at the beginning of this
technology. It is recommended that the Corps
project for concrete cured at 5C. That necessi-
use the information in Appendix C to update its
tated the need to search for a new admixture. The
specifications. The information does not iden-
admixture DP, developed in this project, met the
tify acceptable chemicals but, rather, identifies
preset requirements. Therefore, DP is recom-
how they should perform when used at low
mended for use in winter concrete applications in
temperature.
which the internal temperature of concrete may
The return in federal research and develop-
be allowed to drop down to 5C. The air tem-
ment investment in a new technology, such as
perature may be at even lower temperatures as
antifreeze admixtures, may be slow because of
long as the internal concrete temperature stays at
the standards, liability, and marketing consider-
5C. DP is not currently commercially available
ations described above. However, the economic
off the shelf. The investment needed to bring such
opportunity to increase the construction season in
a new admixture through the distribution chan-
a significant portion of the United States is a real
nels, including storage tanks, advertising, techni-
possibility that should not be ignored.
cal advisor training, etc., is significant. At this
The U.S. Army could benefit from adding the
point, WRG has decided not to make this invest-
antifreeze admixture method to its menu of options
ment until the winter concrete market grows.
for winter operations. The experience in military
However, WRG is willing to supply this admix-
construction could provide confidence in the use of
ture upon request for significant projects.
antifreeze admixtures in the civilian sector.
The antifreeze admixture KC1 was patented by
the U.S. Army. This admixture is made of two
generic chemicals usually supplied in powder
TECHNOLOGY TRANSFER
form. They can be purchased from any chemical
AND MARKETING PLAN
supplier. KC1 is made of three weights of sodium
nitrate (sodium nitrite works as well) and one
Objective
weight of sodium sulfate. The recommended dos-
To disseminate and publicize the findings of
ages vary from 6 to 8% by weight of cement. KC1's
the research project, and develop a marketing strat-
major disadvantage is that it adds alkalis to the
egy as appropriate.
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