Ccwd nsc pervious pavement- for meca
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Ccwd nsc pervious pavement- for meca
- 1. NSC Pervious Pavement Demonstration Grant MECA March 4, 2011
- 2. The Beginning Ponding problem in a corner of a SuperRink parking lot. October 6, 2009
- 3. Then National Sports Center, Blaine, applied for $3000 Demonstration Grant from CCWD to install pervious concrete.
- 4. 1 st Install October 7 -9, 2009
- 5. 1 st Install October 7- 9 , 2009
- 6. 1 st Install - curing October 15, 2009
- 7. Inspection 4.5 Months later
- 8. Raveling
- 9. Raveling along turning radius
- 10. 1. Next Steps–Informal Infil Test March 18, 2010
- 11. 1. Infil Results
- 13. 3. Next Step-Determining Cause
- 14. Site Core 2 Core 1
- 15. Analysis Core 1 Core 2 1 2
- 16. Findings Core 1 Core 2 Both cores exhibited fracturing
- 17. Findings Carbonation in both cores Core 2 Core 1
- 19. 5. Decision Re-install in warmer weather
- 20. 2nd Install August 25, 2010 Cost split amongst contractors, NSC
- 21. 2.5 Weeks later September 13, 2010
- 22. Maintenance Cooperation with neighbor Blaine PW Weekly
- 23. 2011 – 5.5 months later
- 25. Next Step - Repeat Infil Test
- 26. Vehicle loading
- 27. again!
- 31. Next Steps Repeat Process Onsite Meeting Involved parties "Successperts" Mark Maloney-Shoreview Len Palek-MNDOT Jon Lee-Cemstone Mary Vancura-MS research
- 32. Next Steps Re-determine Cause Explore Solutions Re-install pervious concrete Replace w/ pervious asphalt Other -TBD Patch repair
- 36. Thank You Acknowledgements: TJ Helgeson, CCWD Tom Gile, CCWD
Editor's Notes
- Spring melt trash shown above. Plastic and glass Bottles also present floating in Ditch 41 and along the east bank of the parking lot.
- Red = most ravelling = turning radius area
- Agreed upon that the concrete was not holding up and labeled as “failure”. Why it failed was not evident without further testing.
- Phenolphthalein is an colorless agent which measures pH. The agent turns pink to purple when contacted with high pH, in this case concrete. The first fracture in core 2 occurred while removing the core while the second fracture occurred while cutting into thin sections.
- Both cores show fracturing suggesting failure occurred throughout the section, not just under the area of vehicle loading. Core 2 appears to be worse but this would not be the case if both cores were subject to the same traffic loads. Summary: both cores have failed.
- Core 1 –The “travel distance” of carbonation from fracture lines indicates these fractures occurred early on in the lifespan of this concrete section. New fractures show little carbonation as air hasn’t been in contact with the cement long enough for the reaction to occur. Core 2 – Carbonation forms when CO2 in the air mixes with calcium in cement. A high degree of carbonation (yellowish colors) suggest a large amount of air (voids) in the cement material. These voids are generally eliminated through the hydration process. In this case, temperatures were determined inadequate hampering this process and leading to weak concrete.
- primarily hydration
- Use air sweepers
- Infiltration rates are much better with the 2 nd installation than with the 1 st install. However, significant raveling is still occurring at the same if not increased rate compared to the 1 st install.
- snowbank pocked with pervious aggregate
- Argument can be made that the NSC pervious has not “failed” as it is still infiltrating. However, nobody would be happy with the aesthetics of the pervious section. Does this constitute failure in future agreements?
- Issues: Curing time; weather, site, blankets re: blankets http://envirocreteinc.com/lessons.html Who takes care of the plastic? curing is the most critical step in the whole placement process. Getting the plastic placed as quickly as possible is critical, but just as critical is the maintenance of the plastic for the entire 7 day period of time. It is typical that the maintenance of the plastic be placed onto the general contractor because of the cost issues. This however, has been a less than acceptable way of making sure the plastic is to be maintained because the general has got lots of other issues and they fail to make sure the plastic is properly secured. We suggest that the contract be properly funded to have one of your workers inspect and maintain the plastic at least once a day during the 7 day curing process.