Off-the-Shelf Antifreeze Admixture for Concrete
Initial Laboratory Investigation
CHARLES J. KORHONEN AND SHERRI A. ORCHINO
INTRODUCTION
TEST PROGRAM
It has long been a goal of the concrete industry to
The objective of this study was to explore the low-
emplace fresh concrete during the winter without ther-
temperature performance of commercial admixtures
mal protection. A few years ago private industry es-
that conform to ASTM C 494. A number of companies
sentially achieved that goal by developing two proto-
sell these admixtures, but because of study constraints,
type antifreeze admixtures (Korhonen and Brook 1996,
admixtures from only one company were chosen. (A
Korhonen et al. 1997b). The prototypes enabled con-
follow-on study should be conducted to evaluate ad-
crete to gain strength and to resist freezing down to
mixtures from the other companies, as some admix-
5C (23F); normal concrete freezes at these tempera-
tures might perform better than those of this study. The
tures. However, partly because of resistance to change
follow-on study should also consider compatibility
and partly to find an admixture that works at lower tem-
between the chemicals of one company versus another,
peratures, antifreeze admixtures have not been made
as it might be best to combine admixtures from
available to the general public.
different companies.) The prototype admixtures men-
In 1998, we reported that we did not have to wait
tioned above would serve as the benchmark against
until the ultimate antifreeze admixture was marketed--
which the formulations tested in this study could be
an interim one could be formulated from the admix-
judged.
tures already developed for concrete. In a study con-
Admixtures
ducted for the Tennessee Valley Authority (TVA), an
antifreeze admixture was successfully fashioned from
Neither the manufacturer nor its product names will
the seven categories of set-controlling and water-
be disclosed in this report. The admixtures chosen met
reducing admixtures approved for use in concrete by
one or more of the requirements of six of the seven
ASTM C 494 (ASTM 1997c, Korhonen et al. 1998).
ASTM categories. Table 1 lists those categories, their
Combining set-accelerators with other chemicals that
functions, and their affect on initial setting. The cat-
could act as freezing point depressants developed the
egory omitted was Type G, high-range water reducing
admixture. Not only did the admixture protect the con-
and retarding admixtures. It was felt that the water re-
crete from freezing, it also was immediately accept-
ducing and retarding function available in Type D made
able to TVA engineers because its components com-
Type G unnecessary for this test. In addition, calcium
plied with ASTM C 494.
chloride, being perhaps the oldest and best-known ac-
It was apparent from the TVA study that more could
celerating admixture, was added to this group.
be done to optimize these chemicals for use at low tem-
The ASTM categories serve a variety of functions.
perature and to develop protocol for their use. This
Water-reducing admixtures lessen the amount of water
paper reports on the initial laboratory study to develop
required to maintain workability and consequently the
an antifreeze admixture from commercial admixtures.
amount of water that has to be protected from freezing.
Work is continuing.
Accelerating admixtures speed up the normal process
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