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49
Table 3.13. Summary of 48-hour percent absorption for the
durability test, Stage III.
Crack
width Control DegaDeck® DuralPrep® A.C. SilACT®
(in.)
With Without With Without With Without
0.000 2.886
REM 800 REM 800 REM 800 REM 800 REM 800 REM 800
0.007 4.375 0.000 2.783 0.000 0.000 0.195 3.462
0.016 4.839 0.000 2.907 0.000 0.000 0.106 2.912
0.033 4.772 0.000 0.000 0.137
0.054 5.158 0.000 0.002 0.257
almost no measurable absorption of water. However, without treated with REM 800 were able to prevent water absorption
the REM 800, the cracks were not able to be bridged nor better than the specimens that were not treated with REM 800.
sealed, and water was allowed to seep into the open cracks. The material packed into the crack created a bridge over which
DegaDeck® is too thin to bridge even the smallest cracks the less viscous water resistant sealants were allowed to lay,
tested. For the specimens without REM 800, the specimens forming an unbroken seal across the entire surface.
with a crack size 0.016 in. absorbed more water than the This experiment was designed to exaggerate actual bridge
specimens with a crack size 0.007 in. However, neither ab- conditions to which end zone cracks would be exposed. In ser-
sorbed as much water as the control group that did not vice, the crack surface would not be continuously under water,
have a sealant. DegaDeck® Crack Sealer Plus has performed as the specimens were, but the exposure to wet environmental
well in all phases of testing and has been near the top in conditions would extend for a much longer period of time.
each experiment.
SilACT® did not perform as well as the other two sealants
tested in this experiment. It performed relatively well with REM 3.4.5 Chemical Composition of the Sealers
800, but did not perform well without REM 800. With REM In order to help design engineers specify the appropriate
800, only a small amount of water was allowed to seep into the sealer for a project, Table 3.14 lists the sealers used in this
concrete. However, in all cases water was continuing to seep study and their chemical composition.
into the concrete from Day 1 to Day 2, and would continue to
do so as time went on. The sealant was thin enough that, with-
out REM 800, the product was not able to bridge the void cre- 3.5 Field Inspections of Bridges
ated by the crack. This left a large opening that water was able
3.5.1 Introduction
to pass through and absorb into the concrete. The water that
absorbed into the SilACT® specimens was still less than the The objectives of the field inspection of highway bridges
water absorbed by the control group that did not have a sealant. were to determine the following:
The control group absorbed the highest volume of water, as
expected. The results in Tables 3.10 through 3.13 also show a 1. Does the width of end zone cracking change with time?
relationship between the amount of water absorbed and the 2. If end zone cracking was detected at the precast plant and
crack width. Typically, wider cracks absorbed more water, and no repair was conducted, do these cracks lead to corrosion
narrower cracks absorbed less water. This is not apparent in all of the strands and bars, or delamination of the concrete?
cases, but most of the specimen results follow this statement.
These results are different than those acquired in Stage II of To investigate these issues, the research team selected two
testing. This may be due to procedural error and the fact that pilot states, Nebraska and Virginia. Two bridges were selected
there were multiple specimens from which to take an average. from Nebraska and three bridges were selected from Virginia
By Stage III, the team had become more familiar with the test- for field inspection. The inspection process included
ing procedure and would have been more careful with the
sealant application. · Collection of reports for inspections conducted at the plant,
The team was able to propose that when using thin sealants, examination of the reports, and identification of repair
packing cracks with a thick cementitious material allows the method and material;
cracks to be closed when the sealant alone is not adequate. In · Collection of inspection reports for the bridges in ser-
order to make this a universal statement and to avoid confu- vice; and
sion on limits on sealant viscosity, a packing material is recom- · Research team visits of the bridges under study for in-
mended with the use of all sealants. Typically, the specimens spections that included observation of crack growth since
