membrane behaved. Table 3 was developed from
Table 2. Comparison of adhesion values.
these data to directly compare ultimate strength
and elongation of the membranes as a function of
Adhesion* (lbf/in.)
temperature.
Manufacturer
Average
Maximum
Minimum
Table 3 shows that, though the membranes are
not all alike in strength, they all tend to become
Polyguard
11.20
19.42
6.75
stronger at lower temperatures. Starting at room
14.82
43.05
0.68
temperature, the Polyguard membrane appears to
Soprema
9.54
29.02
1.34
be the strongest membrane. The word "appears"
11.13
36.32
0.00
is used because the membrane could not be pulled
apart. During the testing the Polyguard membrane
NEI
†
†
†
continually slipped out of the grips, even when
10.19
14.98
5.23
folded around a steel dowel and reclamped into
W.R. Grace
6.39
11.46
2.87
the grips. However, based on the results from the
10.52
17.93
4.18
other temperatures, when the membranes broke,
we estimate Polyguard's room temperature ten-
Protecto Wrap
8.35
14.70
5.23
sile strength to be approximately 200 lbf/in.
7.05
9.25
4.45
(35,000 N/m). As mentioned, each membrane in-
Royston
3.17
6.97
1.71
creased in strength at lower temperatures.
4.93
9.61
2.88
Royston, the weakest at room temperature, more
than doubled in tensile strength when tested at
*From Appendix B.
†Samples not available.
The top row of readings for each material is from the
supplier-made samples and the bottom row from the CRREL
samples.
25.4 mm
(1.0 in.)
brane must either be strong enough to resist the
tensile force caused by crack movement or stretch-
25.5 mm
able enough to accommodate it. This study re-
(1.0 in.)
viewed ASTM standards D412, D638, D882, D2523,
and D4885 before developing a testing protocol to
evaluate the ability of waterproofing membranes
to resist splitting and elongation at various tem-
peratures, including below freezing.
254.0 mm
Procedure
(10.0 in.)
Tensile strength and elongation were deter-
mined at five temperatures (70, 40, 23, 14 and
4F [21, 4, 5, 10 20C]), by pulling apart
three dogbone-shaped specimens per membrane
(Fig. 5) at a grip separation rate of 4 in./min. Prior
to testing, the specimens were conditioned one
63.5 mm
hour at the appropriate test temperature. Figure 6
(2.5 in.)
shows the test setup.
77.8 mm
Results and discussion
(3.1 in.)
Test results for tensile strength and elongation
39.7 mm
(1.6 in.)
are shown in Appendix C and Table 3. Appendix
C shows loadstrain curves for each membrane
tested at five temperatures. We will not discuss
50.8 mm
50.8 mm
each curve, but the reader is encouraged to review
(2.0 in.)
(2.0 in.)
Appendix C to understand how the measurements
were obtained and to get a sense for how each
Figure 5. Dogbone tensile specimens, ASTM D 2523.
8
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