Table 10. Relative performance of specimens
consuming and expensive to perform, but equip-
in each test.
ment costs are less for the C 1262 method, and
some laboratories are equipped to perform it. Due
SRW
ASTM
ASTM
ASTM
ASTM
to the cost and time needed to perform these tests,
set
C 666
C 1262
C 457
D 4414
additional future consideration should be given to
A
Excellent
Excellent
Good
Good
the use of microscopic evaluations, MIP, and other
G
Poor
Fair
Good
Fair
methods of providing indicators of potential unit
H
Poor
Good
Fair
Fair
durability.
I
Poor
Poor
Good
Poor
J
Poor
Poor
Poor
Good
K
Good
Poor
Excellent
Poor
FIELD DEMONSTRATION
fied in one of four categories: excellent, good, fair,
Objective
A concrete masonry wall consisting of 251/2
and poor. These ratings are not defined in any of
the referenced methods. They are used simply for
blocks per row that was five blocks high was con-
the purposes of this report to evaluate potential
structed in northern Michigan at the U.S. Army
correlation between the results.
Corps of Engineers Soo Locks, Sault Ste. Marie, in
March 1995. Each block was nominally 203 203
In general, the two freezethaw test methods
406 mm (8 8 16 in.). The objectives of this
used, C 666 and C 1262, provided fairly similar
results in identifying the relative performance of
experiment were to demonstrate the practicality of
the sets of units, with several notable exceptions.
using antifreeze admixtures in masonry mortar
For example, both methods indicated that set A
and to compare it with conventional cold-weather
was clearly the most durable of all sets evaluated,
masonry practices.
and both methods demonstrated similarly poor
performances for sets I and J. However, the results
Temporary enclosure
contrasted regarding the remaining sets G, H, and
A temporary enclosure was erected in which
K. Method C 666 indicated that sets G and H per-
the wall was constructed. Half of the shelter was
formed worse than sets I and J and that set K per-
heated and half was unheated. A canvas separated
formed well. These results are nearly opposite to
the two halves. Conventional type M masonry
those of Method C 1262, which showed G and H
cement mortar was used to build the section of
to be good performers and set K to be a poor per-
wall within the heated portion of the shelter, while
former similar to that of I and J.
the same type of mortar with the addition of an
The microscopic examination and MIP (C 457
antifreeze admixture was used to build the section
and D 4404, respectively) results for sets A, G, and
of wall within the unheated section of the shelter.
H demonstrated some promise as a method of
predicting freezethaw performance using one of
The mortar
the test methods. The same was not the case for
All mortar used for building the wall was hand-
sets I, J, and K. However, the less durable aggre-
mixed with hoes in a mixing trough in the heated
gates used in each of these last three sets may
side of the shelter. The ingredients, which were all
have resulted in the poor correlation between test
preheated to the temperature of the enclosure,
methods, since the microscopic examination and
were preweighed and combined in the propor-
MIP can only evaluate the paste structure. The
tions shown in Table 1. The antifreeze admixture
microscopic examinations can often give indica-
KC1 was dissolved in a portion of mixing water.
tions of the soundness of the aggregate, however.
The sand and cement were thoroughly combined
Potentially frost-susceptible aggregates were
before water was added. The amount of water
identified in examinations of specimens from sets
added was estimated by eye by the mason until a
I, J, and K.
desired consistency was achieved. The mortar was
With the limited data available here, it appears
retempered as needed. The average water con-
that Method C 1262 may be a better method for
tents of the as-mixed mortars were 12.9 and 13.4%
evaluating freezethaw durability of these con-
for the conventional and the antifreeze mortar,
crete masonry related units. The C 1262 results
respectively.
show better differentiation between sets of units.
The C 1262 test results compare better with the
Constructing the wall
results of microscopic evaluations and mercury
Both wall sections were laid in running bond
intrusion porosimetry. Both methods are time-
with faceshell mortar bedding using conventional
23
Previous Page
