1. Chris Sajbel Pecora Corporation
Roadway Joints
Chris Sajbel Pecora Corporation

2. Movement Capability..
Movement Capability- The +/- percent value that indicates the amount of movement the sealant can take in “extension (+)” and/or “compression (-)” from it’s original cured joint width.
Sealants are characterized by their type and their movement capabilities:
+/- 12.5%
+/- 25%
+/- 50%
+100%/-50%
These are the 4 standard classifications of joint sealants. Decisions should be made accordingly.

3. FAA Joint Types
FAA Publication AC 150/5320-6D

4. Bond Durability or Movement Class
ASTM C-719
Class / %
Class 25 +/- 25
Class 50 +/- 50
Class / -50
Must pass 10 cycles after aged 160 F and water immersion with extension temperatures down to -15 F
Look for SWRI Validation

5. Joint Configuration Width to depth ratios guidelines
Purpose: Maximize sealant performance
Vertical Joints
Joints up to 1/2 ” wide: 1:1 width to depth
Joints up to 1.0” wide: 2:1 width to depth
Joints > 1.0”: Max .50” depth
Horizontal Traffic Joints
Joints up to 1/2 “ wide: 1:1 width to depth
Joints > 1.0” (pedestrian) : :1 width to depth
Joints > 1.0” (vehicular): 2:1 width to depth

6. Sealant Types Cold applied – Polyurethane, STPU, Silicone Hot applied
Preformed
Polychloroprene elastomeric (neoprene) compression sealant
CSS-69
There are three categories of joint sealant materials, as shown in the accompanying slide. Selection of the sealant type is generally based on the specific design details of the project, desired performance, and cost.
DISCUSS THE RELATIVE MERITS OF EACH OF THESE SEALANT TYPES IN TERMS OF INITIAL COST AND EXPECTED LONGEVITY. ASK WHAT TYPE OF SEALANTS ARE ROUTINELY USED. ARE DIFFERENT SEALANTS USED FOR MAINTENANCE ACTIVITIES THAN FOR NEW CONSTRUCTION?

7. Sealant Types Cold Applied Hot Applied Preformed CSS-71
Cold Applied Partial Depth
Cold Applied Full Depth
Pre-formed Seal
CSS-71
Figure: The various sealant types have different requirements for the configuration of the sealant reservoir. Note that cold and hot applied sealants typically require a backer rod or similar device, while the preformed sealants do not.
POINT OUT THE DIFFERENT CONFIGURATIONS OF THE JOINT RESERVOIR REQUIRED FOR EACH TYPE OF SEALANT. BRIEFLY DISCUSS THE REASONS FOR THE VARIOUS SHAPE FACTORS.
Cold Applied
Hot Applied
Preformed

8. Surface Prep Flush joint with water to remove sawing residue
Sand blast vertical faces of joint
Remove sand blasting residue with oil-free air
The vertical faces of the joint must be clean for the sealant to adhere
Always check the air/water trap on the air compressor

9. Backer Rod Polyethylene foam (cold)
Cross-linked polyethylene foam (hot or cold)
CSS-72
The shape factor of a formed-in-place sealant is critical for optimum performance. Using a backer rod assists in controlling the proper sealant shape. Backer rods also prevent the sealant from flowing out of the bottom of the widening cut and adhering to the bottom of the reservoir. The backer rod diameter should be approximately 25 to 50% greater than the reservoir width to ensure a tight fit.
Materials used for backer rods include the following:
Polyethylene Foam: Polyethylene foam is a closed-cell foam that does not absorb water and is moderately compressible. Because polyethylene foam may melt with hot-applied materials, it is better suited for cold-applied sealants.
Cross Linked Polyethylene Foam: Cross linked polyethylene foam is compatible with hot-applied sealants. It is a closed-cell foam that does not absorb water and is moderately compressible, but will not melt in contact with hot-applied sealant.
BACKER RODS ARE VERY IMPORTANT IN ESTABLISHING THE PROPER DEPTH AND CONFIGURATION OF SEALANT. THE BACKER ROD DIAMETER IS CONTROLLED BY THE RESERVOIR WIDTH. THE DEPTH SHOULD BE ACCORDING TO THE MANUFACTURER’S RECOMMENDATIONS FOR THE SPECIFIC SEALANT.

10. Backer Rod Installation
Handle
Backer Rod
Reservoir
Insertion Wheel
CPR-257
Figure: For most work a dual-wheeled roller is recommended. However, for rehabilitation work with slightly faulted joints, a single-wheeled roller may work better. The roller will allow you to reference insertion depth to the low side of a faulted joint. Sealant installation will then be at the appropriate depth. It also recesses the sealant enough to allow sealing the joints before diamond grinding.
ENGINEERS MUST ENSURE THAT THE MINIMUM INSERTION DEPTH IS OBTAINED. THIS IS MADE POSSIBLE BY USING A ROLLER WITH THE RIGHT DIMENSIONS TO MATCH LOCAL SPECIFICATIONS AND CONDITIONS.