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(a) Pipewipe® (b) DuralPrep® A.C. (c) Transpo Sealate® T-70 (d) Xypex® Concentrate (e) DegaDeck® Crack Sealer Plus
Figure 3.50. Specimens coated in sealants.
two-part substance comprised of liquid and powder hard- (2) DuralPrep® A.C., (3) Pipewipe®, (4) Transpo Sealate® T-70,
ener. It is recommended for horizontal surfaces only. How- and (5) Xypex® Concentrate.
ever, the team found that the product performed well on The top performing sealants retained for Stage II of the dura-
vertical surfaces, such as girder webs, and did not flow off bility tests were DegaDeck® Crack Sealer Plus, DuralPrep® A.C.,
the exterior. DegaDeck® Crack Sealer Plus was the best and Transpo Sealate® T-70.
performing sealant of the five tested. It also had a very easy
workability and mixing procedure. However, when mixed,
the chemical is highly volatile and produces harsh, poten- 3.4.3 Durability Test, Stage II
tially dangerous fumes. It is also a skin and eye irritant. The
For the second stage of the durability test, the team observed
fumes, as well as the liquid, are flammable.
how assorted sealers perform in preventing water from pen-
etrating into concrete specimens exhibiting various sizes of
3.4.2.2 Stage I Test Results cracks. The procedure was modified from two ASTM Stan-
Tables 3.5 and 3.6 present a summary of the percent absorp- dards, G109-99a Standard Test Method for Determining the
tion of each specimen at 24 h and 96 h, respectively. Also, these Effects of Chemical Admixtures on the Corrosion of Embedded
tables provide the average, standard deviation, and variance Steel Reinforcement in Concrete Exposed to Chloride Environ-
for the five sealants. ments, and D6489-99 Standard Test Method for Determining the
The five sealants were rated from the analysis of the absorp- Water Absorption of Hardened Concrete Treated with a Water
tion results at 24 h and 96 h and ease of application, and from Repellent Coating. (ASTM Standard D6489-99 is provided in
the best to the worst were (1) DegaDeck® Crack Sealer Plus, Appendix E.)
Table 3.5. Summary of percent absorption of all sealants
at 24 hours.
Sealant
®
Specimen Control DuralPrep Transpo Xypex® DegaDeck®
Pipewipe®
Specimens A.C. Sealate® T-70 Concentrate Plus
1 2.65% 1.58% 0.38% 2.52% 2.99% 0.62%
2 2.49% 1.31% 0.37% 2.45% 3.16% 0.52%
3 2.43% 1.71% 0.45% 2.59% 3.12% 0.44%
4 2.65% 1.41% 0.58% 2.23% 3.15% 0.29%
5 3.02% 1.38% 0.37% 2.13% 3.21% 0.27%
6 3.01% 1.39% 0.38% 2.29% 3.15% 0.68%
7 2.74% 1.50% 0.51% 2.59% 3.24% 0.23%
8 2.80% 1.55% 0.48% 2.53% 3.14% 0.16%
9 2.69% 1.46% 0.68% 2.05% 2.55% 0.18%
10 2.74% 1.54% 0.62% 2.71% 3.00% 0.15%
Average 2.72% 1.48% 0.48% 2.41% 3.07% 0.35%
Stand. Dev 0.190 0.118 0.112 0.219 0.199 0.195
Variance 0.036 0.014 0.012 0.048 0.040 0.038
Rating
3 2 4 5 1
(1 = best, 5 = worst)
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Table 3.6. Summary of percent absorption of all sealants
at 96 hours.
Sealant
®
Specimen Control DuralPrep Transpo Xypex® DegaDeck®
Pipewipe®
Specimens A.C. Sealate® T-70 Concentrate Plus
1 2.76% 1.67% 0.66% 2.92% 3.23% 0.82%
2 2.60% 1.39% 0.63% 2.81% 3.40% 0.67%
3 2.54% 1.80% 0.65% 2.98% 3.35% 0.58%
4 2.77% 1.48% 0.83% 2.60% 3.40% 0.47%
5 3.14% 1.45% 0.63% 2.55% 3.46% 0.42%
6 3.15% 1.47% 0.60% 2.70% 3.44% 1.05%
7 2.86% 1.59% 0.74% 2.99% 3.52% 0.34%
8 2.92% 1.61% 0.81% 2.89% 3.36% 0.87%
9 2.81% 1.55% 1.04% 2.36% 2.74% 0.27%
10 2.87% 1.63% 1.11% 3.07% 3.27% 0.26%
Average 2.84% 1.56% 0.77% 2.79% 3.32% 0.58%
Stand.
0.199 0.122 0.177 0.226 0.219 0.273
Dev.
Variance 0.040 0.015 0.031 0.051 0.048 0.074
Rating
3 2 4 5 1
(1 = best, 5 = worst)
The sealants chosen for this experimentation are the three 800, rubbed into the cracks by hand, and then sealed with the
best-performing sealants from the first durability test (Dega- same sealant as the first set. An additional set was made as
Deck® Crack Sealer Plus, DuralPrep® A.C., and Transpo the control, where the specimens were not repaired with any
Sealate® T-70) along with SilACT®, which was recommended sealant at all and did not contain any artificial cracks. Table 3.7
by Central Pre-Mix Prestress Co. of Washington State. The shows the test plan.
specimens were made from the same concrete mix design, The specimens were placed on their sides and the selected
with a concrete strength of about 5,000 psi. Although this con- sealants and REM 800 were applied to their specific sets. This
crete mix is relatively more porous than the concrete normally orientation mimics the orientation of the cracks on the webs
used in precast girders, it was used to amplify the amount of of production girders. Care was exercised not to leave any con-
water absorbed if the sealers failed. crete surface uncovered or to allow any air bubbles to form.
The REM 800 was rubbed into the cracks by hand but the
3.4.3.1 Stage II Test Procedure sealants were applied with a roller.
Once all of the specimens dried, they were turned upright
The concrete specimens were made in the structures labora- and a 3-in.-tall rectangular plastic dam was built on the top
tory of the University of Nebraska, in the form of 3 × 3 × 12-in.
rectangular prisms. Artificial cracks were formed with metal
and plastic shims, penetrating down 2.25 in. from the top sur-
face of the specimens and measuring 9 in. in length, as shown
in Figure 3.51. These shims were placed in the concrete while
it was still wet and removed when it began to set. The artifi-
cial cracks were produced in a variety of widths, ranging from
0.007 to 0.054 in.
After all specimens were fabricated, they were placed in
a draft oven for 24 h to remove any moisture. When cooled,
their weight was recorded as WA, and then the sealants were
used to cover the four sides and bottom face of each specimen,
leaving only the top surface containing the crack uncoated.
These sides were covered to prevent moisture from either
entering or escaping the areas not being tested.
There were two sets of specimens for each sealant, with each
set containing prisms with cracks of each available size. The
first set was sealed only with the specified sealant. The second
set had a Hilti® Brand hydraulic cementitious material, REM Figure 3.51. Specimens with metal shims.
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Table 3.7. Plan for the durability tests, Stage II.
Transpo DuralPrep®
DegaDeck® SilACT®
Crack Sealate® A.C.
Control
Width With Without With Without With Without With Without
Batch
(in.) REM REM REM REM REM REM REM REM
800 800 800 800 800 800 800 800
Number of Specimens, Stage II (Total = 46 Specimens)
0.000 1
0.007 1 1 1 1 1 1 1 1 1
0.012 1 1 1 1 1 1 1 1 1
0.016 1 1 1 1 1 1 1 1 1
0.033 1 1 1 1 1 1 1 1 1
0.054 1 1 1 1 1 1 1 1 1
Total 6 5 5 5 5 5 5 5 5
surface of each specimen around the artificial crack so that 3.4.3.2 Stage II Test Results
water could pond on the repaired surface. Waterproof caulk-
The test results show that packing larger cracks with a thick,
ing material was used to secure the plastic walls in place, as
cementitious material (REM 800) allowed the cracks to be
shown in Figure 3.52. With the dam in place, the specimens
closed, while repair with a sealant alone failed in most cases
were weighed, recording the data as W1.
with large cracks. Typically, the specimens with REM 800 were
The specimens were all placed face up in an area where
able to keep the water out better than the specimens without
they would not be disturbed. Each dam was then filled to the
REM 800. The material packed into the crack created a bridge,
top with water. The specimens were given the opportunity to
over which the less viscous water-resistant sealants were allowed
absorb water for 24 h. Every effort was made to ensure that
to lay, forming an unbroken seal across the entire surface.
the dam remained filled with water at all times. At 24 h, the
Without REM 800, the sealants with a water-like consistency
water in each dam was emptied. Then, the specimens were
(DegaDeck®, Transpo Sealate®, and SilACT®) were not able to
towel dried. The weight of each sample was measured and
adequately fill the large-sized cracks when applied on a ver-
recorded as W2. The percent of water absorption by each
tical surface. Table 3.8 gives a summary of the 24-h percent
sample can be found using the following equation:
absorption of the specimens.
100 i (W2 - W1 ) This experiment was designed to exaggerate actual bridge
Percent Absorption = (Equation 1) conditions to which end zone cracks would be exposed. In
WA
service, the crack surface would not be continuously under
Where WA is the weight of the concrete specimen after dry- water, as the specimens were, but the exposure to wet envi-
ing, but before exposure to the sealant and before dam place- ronmental conditions would extend for a much longer period
ment, W2 is the weight of the sealed specimen after soaking, of time.
and W1 is the weight of the sealed specimen before soaking. DegaDeck® Crack Sealer Plus was effective when coupled
with REM 800, but without the hydraulic cementitious
material enough water penetrated into the crack for it to be con-
sidered ineffective. About half of these DegaDeck® specimens
remained relatively water resistant while the remaining seals
failed. The sealant was not thick enough to be able to bridge the
gap created by the crack on its own, as shown in Figure 3.53.
Transpo Sealate® was not considered effective with or with-
out REM 800. Except for a few outliers, the specimens contain-
ing REM 800 collectively had a much lower percent absorption
of water than the specimens without REM 800. The ineffective-
ness of Transpo Sealate® may be attributed to the thin, water-
like consistency of the product. When applied to the vertical
surface, most of this sealant flowed off of the sample. There-
fore, the layer that remained was not thick enough to prevent
water infiltration. The product is recommended for horizon-
tal application and the experiment confirms that this is where
it would be most useful. Figure 3.54 shows the specimens
Figure 3.52. Specimens with water dams. sealed with Transpo Sealate®.
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Table 3.8. Summary of 24-hour percent absorption for the durability
test, Stage II.
Crack
Width Control DegaDeck® Transpo Sealate® DuralPrep® A.C. SilACT®
(in.)
With Without With Without With Without With Without
0.000 4.28 REM REM REM REM REM REM REM REM
800 800 800 800 800 800 800 800
0.007 1.81 0.22 4.10 2.06 4.63 0.42 0.66 0.09 2.17
0.012 1.49 0.11 1.44 2.96 0.87 0.51 2.78 0.13 0.46
0.016 2.59 0.36 0.69 2.82 1.03 1.07 3.25 0.19 1.45
0.033 4.19 0.35 0.37 2.29 4.04 0.33 1.46 0.17 1.94
0.054 1.69 0.08 3.81 1.34 4.03 0.72 0.54 0.15 2.43
(a) With REM 800 (a) With REM 800
(b) Without REM 800 (b) Without REM 800
Figure 3.53. Specimens coated with DegaDeck®. Figure 3.54. Specimens coated with Transpo Sealate®.
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DuralPrep® A.C. was moderately effective with an under- hard, water-resistant outer shell that covers the specimen, as
coating of REM 800, but was not effective without it. The is the case with the other sealants. Instead, the water-resistant
sealant was mixed by combining a powder with two liquid layer is actually within the concrete. Without the hard, outer
chemicals. This created a thick, slurry-like liquid that was able layer, there is nothing to bridge the crack gap. The strength of
to bridge the space created by the cracks, even without REM SilACT® comes from being able to be soaked into the concrete.
800 and with the largest 0.54-in. crack. DuralPrep® A.C. was This is why it performed well after soaking into the REM 800
the only sealant of the four tested that did not gap when applied layer. Without the patching material, the crack was left open
over the crack, especially when voids appeared at the crack and SilACT® was not able to soak all of the way into the crack
location. However, the product performed well when the when the opening was located on a vertical surface. If the sur-
specimen was batched with REM 800. Figure 3.55 shows face had been horizontal and the product had been allowed
the specimens sealed with DuralPrep® A.C. to soak all the way into the crack, the results would have been
SilACT® was effective at preventing water penetration with more effective, but this would not be representative of the
REM 800, but was ineffective without the cementitious pack- actual end zone crack position. Figure 3.56 shows the spec-
ing material. The manufacturer states that SilACT® chemically imens sealed with SilACT®.
bonds with the substrate and creates a water-resistant layer just In comparison to what the study team expected, the data
below the concrete surface that repels water but allows gasses had quite a few inconsistent results. It seemed that whether the
to flow through. Therefore, SilACT® has a different method sealant was effective or not depended largely on how well the
of water resistance than the other sealants tested. There is no application was executed. Specimens (such as the 0.016-in.
(a) With REM 800 (a) With REM 800
(b) Without REM 800 (b) Without REM 800
Figure 3.55. Specimens coated with DuralPrep®. Figure 3.56. Specimens coated with SilACT®.
