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What's
Different? BEJS is not like other
foam-based expansion joints. BEJS is supplied precompressed to
less than the joint size. It is held in compression by its
packaging. When released it expands. BEJS, properly sized, is never
in tension in the joint. This is the key to its performance.
BEJS is coated at a width
that exceeds the maximum expected joint opening. Expansion is faster
when hot and slower when cold. The pictures below are of a small piece
of BEJS cut by the contractor to gauge expansion rate before
installation on a hot (95-deg-F) day. Expansion is slower in cold
weather. |
Product Description
The BEJS SYSTEM builds on a track record of over 30 years of sealing
bridge joints with precompressed, impregnated foam sealants.
The system is comprised of:
1) Precompressed, silicone-and-impregnated-foam hybrid installed into...
2)
field-applied epoxy adhesive on the joint faces; with the Pecora 301 silicone
bellows locked to the joint faces with...
3) a silicone sealant band (see
Figure 1).
The BEJS SYSTEM features an innovation in sealant technology in the form
of a patent-pending acrylic adhesive infused into the cellular foam base
material. This new chemistry incorporates a hydrophobic microsphere component never before available in a sealant formulation.
The material features sealing performance significantly greater than any
acrylic impregnated predecessor. In addition, it is odorless,
clean
handling, UV stable, non-staining, and features
low temperature
flexibility not previously available in asphalt, wax, or
isobutylene-based predecessors.
The result is extension of the usability of the product to applications
where asphalt and wax-based predecessors did not work well under
conditions of
thermal shock (rapid opening and closing of joints during
large temperature swings). These applications include joint-face adhered
installations on top decks as well as intermediate decks.
Suitability is further extended to horizontal-plane joint applications
in colder geographical regions to which asphalt and wax-based
predecessors have not previously been recommended.
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Features
Watertight—the tensionless silicone bellows is installed just below the
deck surface. This ensures watertightness is achieved at the deck
surface.
Unlike liquid-applied sealants, compression seals, and inflated
seals, the BEJS SYSTEM does not rely on
adhesion in tension. Instead the material is precompressed in
the factory ensuring that the spring energy of compression is always
pushing back on the substrate.
Non-Invasive Anchoring—there are no hard metal-to-concrete
connections in the system. This includes embedded pins, anchors, screws,
bolts or tracks, trays or rails. The system is locked to the joint faces
by means of the 1) backpressure of the foam; 2) the epoxy adhesive, and
3) the injected silicone sealant band at the joint face to foam and
silicone bellows interface.
Continuity of Seal—as in all EMSEAL expansion joint systems,
continuity of seal through changes in plane and direction is an
essential performance differentiator. Details for watertight,
field-fabricated transitions from deck to wall, at curbs, sidewalks,
parapets, tees, and crosses are available with the BEJS SYSTEM.
Aesthetics & Versatility—Standard bellows color is
black with grey also readily available (other
custom colors are also available), uniform bellows appearance,
double sealing, fuel resistance, and an enhanced ability to handle
variations in joint size are among other system features.
Installation is
fast, easy, and can be staged to preserve partial traffic flow.
Performance
• Capable of movements of +50%, -50% (100% total) of
nominal material size.
• Substrates must be parallel, plumb and capable of resisting approx.
2.5 psi backpressure from the foam.
• Standard sizes from 1/2" (12mm) to 4" (100mm). Other sizes available
subject to review of application: consult EMSEAL.
• Fuel Resistance: Silicone sealant is not degraded by contact with
fuel. Some swelling of the material will normally occur, but it will
return to its original shape upon evaporation of the fuel.
Composition
• BEJS is produced by coating an impregnated cellular foam with
AASHTO-approved, Pecora 301 highway-grade silicone.
• The expanding foam is cellular polyurethane foam impregnated with a
water-based acrylic containing a high performance micro-cellular
additive.
• The silicone external facing is factory applied to the foam at a width
greater than maximum joint extension and is cured before final
compression.
• Silicone application and curing takes place in a factory-controlled
environment. In contrast to field applied liquid sealant and backer rod
installations, no movement takes place during curing that can cause
deformation or stresses in the material.
• When compressed, a bellows is created in the coating. As joint
movement occurs the bellows simply folds and unfolds free of tension on
the bond line, and virtually free of tensile stresses in the silicone
material. Sizes under 1-inch (25mm) have a single-curve convex bellows;
sizes from 1-inch (25mm) through 4-inches (100mm) have a dual-curve
convex bellows.
• The foam provides a resilient backing to the silicone coating, making
the system capable of resisting reasonable transient point loads.
• BEJS SYSTEM is supplied in 6.56 LF (2m) shrink-wrapped lengths
(sticks). It is precompressed to less than the joint size for easy
insertion. After removal from the shrink-wrap and hard board restraining
packaging, it expands gradually.
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UNIVERSAL 90's
(Expanded Universal-90's information)
Factory-Fabricated Terminations and
Transitions—in all EMSEAL
expansion joint systems, continuity of seal through changes in plane and
direction is an essential performance differentiator.
BEJS is manufactured
in straight-run sticks which can be joined in the field to
EMSEAL’s patent-pending
"Universal-90" Transitions and
Terminations.
These factory-fabricated
single-piece 90-degree units have a 12-inch long leg and a
6-inch vertical piece on each end of the elbow.
The Universal-90's are symmetrically coated on both
sides. This allows them to be installed as an upturn
or as a downturn. Either leg can be trimmed in the field
to connect to straight run material or to another Universal-90
when going, for example, up and over a curb and/or parapet.
Universal-90 terminations
end, on the 6-inch leg, in a 45o sealed and mitered end.
This allows termination as a stand alone upturn in a parapet wall or provides a surface
against to which a wall joint system can be married. Flipped over,
the Universal-90 termination unit can be alternatively installed as
downturn termination where a joint runs off the bridge deck. In this use,
the sealed, mitered end provides a drip edge for drainage of water off
the joint.
In addition to guaranteeing
a continuous
waterproof coating, EMSEAL’s
"Universal-90's" allow for
much faster and secure installation by eliminating field cutting
or notching and bending
at angles.
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