1. 2018 Rocky Mountain West Pavement Preservation Partnership-Concrete Joint Sealants
September 11, 2018

2. Who Am I? Born and raised in Michigan. Education-MBA-Marketing.
Moved to Colorado in 2001 for a sales role with Dow Corning
Silicone building sealants.
Silicone Pavement Sealant Program Manager in 2006, still based in Colorado.
This is my 25th year with Dow/Dow Corning.
Met my wife in Colorado and have been married for 12 years.
One son, Jacob.

3. Why Seal Joints? Prevent water infiltration.
Keep incompressible materials out of the joints.

4. Types of Sealant Used For Pavement Application
Silicone
Compression
Foam
Preformed extrusion
Silicone and Neoprene
Hot Applied
Polyurethane
Caulk isn’t just caulk. Silicone and polyurethane are very different. Significant difference among sealants in a family, i.e. different silicones do different things.
Use caution when bringing different sealants together, especially in an uncured state.

5. Sealant Characteristics To Consider
Weatherability.
UV resistance.
Modulus – high modulus (stiffest) to ultra-low modulus (for high-movement joints)
Movement Capability (determined by ASTM C-719)
Adhesion to a variety of materials … primers may be required
Durability and life expectacny when exposed to UV light, moisture and temperature extremes … what are the property changes?
Substrate-What will it need to bond to?

6. Choosing A Sealant Substrate-what will it bond to?
Concrete
Asphalt
Steel
Polymer concrete.
Joint or crack seal?
How long does it need to last?
Joint movement?
Rapid or slow
Bridge vs. slab on grade
Amount of movement?

7. Test Methods Most specifications reference various test methods.
ASTM most common.
Most Fed specs are rather dated. Do any of your states reference these?
Some tests are more important than others for choosing a sealant.
Bond, movement, and weathering tests likely better performance indicators than extrusion rate and tack free.
Some tests such as extrusion and tack free more important for manufacturer quality control for monitoring batch variation.
There can be several tests for the same item such as extrusion.
Field results will be different than lab.
For example extrusion, tack free, full cure.
Review manufacturer batch testing.

8. Test Methods Make sure test methods still active.
I see test methods and specifications referenced that are no longer active in ASTM.
Common tests/specifications I see.
ASTM D 5893
ASTM C 719
ASTM C 793
ASTM C920

9. Test Methods ASTM D 5893 ASTM C 920
This specification covers cold applied, single component, chemically curing silicone sealants that are based on polymers of polysiloxane structures and are intended for use in sealing joints and cracks in portland cement concrete highway and airfield pavements. The specification includes both non-sag and self-leveling types of sealants.
ASTM C 920
This specification covers the properties of a cured single- or multicomponent cold-applied elastomeric joint sealant for sealing, caulking, or glazing operations on buildings, plazas, and decks for vehicular or pedestrian use, and types of construction other than highway and airfield pavements and bridges.

10. Test Methods
Make sure methods specified are appropriate for application.
Understand what you are specifying.
I have seen requests for every batch of sealant tested to ASTM D 5893.

11. Installation-Concrete Condition
New Concrete
Cured sufficiently to install sealant.
Typically 7 days minimum. More is better.
May be exceptions with different mixes and accelerators.
Old Concrete
Must be sound and in acceptable condition.
Dry
The concrete and in the joints.

12. Installation-Weather
Suggested temperature 40°F and rising.
No active precipitation when sealing or immediately before.
Should allow at least 24 hours of dry time if it has rained.
This will vary depending on rain amount and location.
Do not seal at the dew point.
Once sealant is in the joint exposure to some precipitation is ok.

13. Common Reasons for Sealant Bond Issues
Rushing.
Moisture in the joint at the time of sealing.
Insufficient concrete cure time.
Dirt and dust on the joint wall.
Cutting joints too early-raveling.
Previous sealant not completely removed.
Substrate not sound.
Damage to substrate.
Sealant bonded to damaged substrates such as spalls.
Sealant/substrate incompatibility.
Compressors with unfiltered air.
Sealant incompatibility.
Check with manufacturer if installing sealants wet to wet.

14. Random Thoughts Before Discussing Installation
Florida in some instances cut now, seal later.
Do mockups if unsure of substrate.
Don’t immediately assume problems are due to product.
Consider substrate, installation, field conditions, and product.
South Dakota, great example of what to do.
Many years ago had issues with sealant.
Studied.
Modified spec.
Fewer problems with airfield.
Find reputable contractors and develop relationships. Their field experience can be invaluable!

15. Installation-Joint Prep
Joint typically widened for sealant.
1/4” generally suggested minimum.
Necessary joint width may vary depending on expected movement.

16. Installation-Joint Prep
After cutting rinse slurry from the joint.
Then allow the joints to dry.

17. Installation-Joint Prep
Abrasive Blast
Many location do not allow sand or even abrasive blasting. Other materials are used lieu of sand.
If sandblasting is not allowed discuss other option with sealant manufacturer such as high pressure water.

18. Installation-Joint Prep
Blasting Continued
Ensure both joint walls are sufficiently cleaned from the blasting.
Clean deep enough.
Entire surface the sealant will bond to must be blasted.

19. Installation-Joint Prep
Blow out the joint with high pressure air.
90 psi or greater. Not a leaf blower.
A leaf blower may be used as a final clean to blow out loose debris immediately before sealing.
Oil/water separator on the compressor.
Rub joint wall with cloth or finger to check for dust.

20. Installation-Sealant Application
Install backer rod.
25% larger than joint width.
Closed cell or skin to prevent water absorption.
Place deep enough for sealant and sealant recess. Suggest at least 3/8” recess.

21. Installation-Sealant Application
Install sealant to proper recess and thickness.
Various methods of extrusion.
Drum pump, pail pump, bulk gun, cartridge.

22. Installation-Quality Control
Field adhesion test.
Simple test for adhesion, cleanliness, and sealant profile.
Discuss quality control with manufacturer of technology being used.

23. Installation-Quality Control

24. Installation-Quality Control
Test location easily repaired.
Record results.

25. Thank You!
Questions?