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DSM SYSTEM
Installation into Concrete Expansion Joints
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(Click images to enlarge). |
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On this project we are
replacing a failed inflated, "jeene" type expansion joint seal. This
older technology relies on adhesive that is in severe tension during the
joint opening cycle. It is prone to adhesive failure.
The deck is a factory-topped,
precast double-tee system. |
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The DSM SYSTEM consists of:
- 6.56 LF (2m) sticks of the precompressed foam (in long brown boxes);
- 2-part epoxy adhesive (yellow boxes);
- sausages of silicone (white labeled boxes).
The DSM material expands slower
when cold and faster when hot.
On this cool, early autumn
day, the material was stored in the sun to warm it up to make it expand a
bit faster.
(On hot days, the material
would be installed in the shade, in an air-conditioned van or room, or can
even have bags of ice placed on top of the sticks in the boxes if needed to
slow expansion). |
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With the old, failed joint
system removed and the deck surface along each edge masked with duct tape,
the EMSEAL-supplied epoxy is applied to joint faces.
The glove method is a
rapid-production alternative to using a margin trowel.
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Meanwhile another crew
member opens a stick of DSM by cutting on the hardboard packing to release
the shrink-wrap.
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The first stick is eased
into the joint opening leaving the end to be joined sitting out above the
deck surface.
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Using a sausage gun
and the sausages of silicone shipped with the DSM SYSTEM, silicone is applied across the
silicone bellows face on the end of the stick.
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By lowering the bottom
of the stick into the joint, it is checked for fit.
If not snug enough to hold
its own weight, the material is left alongside the joint to expand a bit
further.
While this is happening
another stick, or sticks, can be opened and laid on the deck alongside where
it will be installed.
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When expanded enough
to support its weight, the stick is inserted and the join made. The
rest of the stick is pushed firmly towards the join. This motion
actually compresses the stick lengthwise further ensuring a tight join.
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The middle portion of
the stick is eased down to its finished height just below the deck surface.
Note that the join is still proud of the deck.
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Finally, the join is
pressed into the joint to the finished height. This final compression
of the join ensures that it is in compression and a tight fit.
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Excess silicone that
squeezes out of the join is tooled away to ensure that the bellows is not
constrained.
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Silicone sealant bands
are injected between the bellows, foam and concrete. The excess
silicone that squeezes out is tooled into a corner bead.
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Duct-tape masking is
removed.
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Installation is
complete...
...and in service the next
day... |
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...taking SUV traffic... |
...car and
pedestrian traffic... |
...and ideal for deck-to-wall
conditions. |
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