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1. Compression Seal
Description:
• Multi-cell Neoprene extrusion installed into epoxy "lubricating
adhesive" applied to joint face.
Advantages:
• Best technology available at its introduction shortly after World
War II
• Predecessor of all modern extruded expansion joint seals
Limitations:
• Anchoring system reliant on adhesive in tension - weakest way to
use adhesive
• Squeezes itself in and out of joints
• Limited movement: Max. joint size limited by relaxed width of seal.
Min joint size limited by complex interior webbing.
• Compression set: loses ability to exert backpressure against substrate
- substrate pulls away from seal
• Rigid "box" structure combined with poor anchoring system cannot
handle vertical differential deflection (up and down) movement.
• Neoprene thermoplastic rubber extrusion cannot be heat-welded.
Terminations and transitions in plane and direction as well as repairs
must be glued. Glue dries out over time. |
2. Inflated Seal
Description:
• Double or single barrier Neoprene thermoset rubber extrusion with
joint face-applied epoxy "adhesive-in-tension" anchoring system
• Seal is inflated during installation to improve bond.
Evolutionary Advantages:
• Reduced interior webbing offers increased movement range over
compression seal
Disadvantages:
• Anchoring system reliant on adhesive in tension - weakest way to
use adhesive.
• Approx. 18 square inches of adhesive in tension per foot of joint.
• Bond line stressed by: peeling action during up and down vertical
deflection; gravel and sand forced by tires into epoxy-to-seal
interface; and standard tension from lateral movement
• Does not protect joint edge. Blockouts with elastomeric header
required to waterproof joint edge and prevent cracking and spalling
• Durable terminations, transitions and repairs difficult. Neoprene
thermoset rubber extrusion cannot be heat-welded. Terminations and
transitions in plane and direction as well as repairs must be glued.
Glue dries out over time.
• Poor extrusion tolerances of Neoprene yields excessive bulk at
flexural nodes in gland, inhibiting movement and excessively stressing
epoxy bond.
• Dependent on extremely smooth joint face. Relies on epoxy to fill
irregularities. |
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3. Multi-Cell Blockout
Adhered
Description
• Blockout-anchored multi-cell extrusion with integral punched
flanges encapsulated in elastomeric concrete nosing material.
Evolutionary Advantages:
• Superior anchoring system to compression seal and inflated seal.
• Elastomeric concrete nosing encapsulates punched flanges, mechanically
anchoring seal using adhesive in shear - strongest way to use adhesive.
• Over 45 square inches of adhesive in shear per foot of seal.
• Not affected by minor irregularities in joint face.
Disadvantages:
• Limited movement. Max. joint size limited by relaxed width of
seal. Min joint size limited by complex interior webbing.
• Rigid "box" structure inhibits vertical differential deflection (up
and down) movement capabilities.
• When retrofitting joint-face adhered technologies, requires cutting of
blockouts. In new construction, blockouts can be formed. |
4. Double Barrier
Blockout Adhered
Description
• Double-Barrier Santoprene thermoplastic rubber extrusion with
integral punched flanges encapsulated in elastomeric concrete nosing
material.
Evolutionary Advantages:
• Latest evolution of gland design. Combines high-movement of double
barrier inflated seal with integral flanges for secure blockout
mounting.
• Elastomeric concrete nosing encapsulates punched flanges, mechanically
anchoring seal using adhesive in shear - strongest way to use adhesive.
• Weldabilty of Santoprene extrusion allows for continuous seal through
changes in plane and direction and offers repairability.
• Over 45 square inches of adhesive in shear per foot of seal.
• Not affected by minor irregularities in joint face.
Disadvantages:
• When retrofitting joint-face adhered technologies, requires
cutting of blockouts. In new construction, blockouts can be formed.
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