APPENDIX A: PERFORMANCE DATA
of the 28-day strength of control mortar cured at
The following four tables present performance
20C. The majority of the strengths are given for
data from mortar made with the chemicals evalu-
7, 14, 28, and 56 days at 20, 5, 10, and 20C.
ated in this testing phase. They present the effect
Where applicable, the mortars are cured for the
of the chemicals on the freezing point of the mix-
first 28 days at the temperature indicated above
ing water in the mortar and on the strength gain
of the mortar cured at 20, 5, 10, and 20C.
each column, then an additional 28 days at room
temperature.
Freezing points were determined by embedding
Table A1 presents the results from chemicals
thermocouples into cylinders of fresh mortar
placed into a 20C room. From the resulting
that had a propensity to cause increased mortar
strengths at 7 days compared to that of control
cooling curve, the freezing point was identified
mortar (see Table 1 in the body of the report for
as the point where the slope of the curve changed.
comparison) when cured at 20C. Table A2 shows
For pure water, the slope of the cooling curve
the results from chemicals that had little tendency
becomes zero until all of the water turns into ice.
to promote early strength or that may have
Since mix water is a solution, its solute concentra-
caused delayed strength, but that provided freez-
tion increases as pure ice freezes out, which pro-
ing point depression merely by being in the mor-
gressively lowers the freezing point. Thus, it is
tar. Table A3 lists the results from chemicals that
that the cooling curve slope only changes and
are liquid regardless of whether they act as accel-
does not become zero as it does with water. The
erators or freezing point depressants. The Table
dosages at which the chemicals were evaluated
A4 chemicals were combined in an attempt to cre-
are presented as a percentage of the weight of
ate an admixture providing both freezing-point
cement in the mortar and as molality--the num-
depression and accelerated strength gain of mor-
ber of solute particles added per kilogram of mix
tar at temperatures below 0C. Time did not
water. Because the formulation of all chemicals
allow for the optimization of chemical combina-
was not known, the number of solute particles
tions. This should be a topic of future study.
added to the mix water could not be provided in
all cases. The strengths are given as percentages
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