2. Background
• Definition of the issue
• Building sustainably in public projects
• The case for Low Impact Development (LID)
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3. Why design with LID in mind…
• As cities continue to be developed, so does the
increased runoff from stormwater due to
increased impervious surfaces
• The runoff gets transported through pipes and
sewers to streams, rivers, lakes and other
bodies of water
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4. Why design with LID in mind
• Runoff from parking lots such as oil, fuel and,
deicing salts harms water quality and aquatic
life, and can cause pollution, erosion, increased
flow of waterways and altered aquatic life
• Pervious concrete is a tool in the LID toolkit that
can help reduce the need for larger
infrastructure by limiting or reducing the amount
of stormwater runoff
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5. What we did
• Provide a pervious concrete pilot project on City
of Tulsa property
• Observe, monitor and measure a defined area of
pervious concrete over a minimum 2-year time
span
• Encourage participation from all interested
public and private entities
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6. Impediments that had to be
addressed
• Lack of education and experience by Oklahoma
contractors
As of March of 2012, only 2 contractors in the state of
Oklahoma were certified by NRMCA (National Ready Mixed
Concrete Association) to be able to place pervious concrete
• Three levels of certification:
• Technician
• Installer
• Craftsman
• http://nrmca.org/Education/Certifications/Pervious_Contractor.htm
for more information on the certification levels
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7. More Impediments…
• Cost – lack of familiarity with pervious concrete
has typically driven up costs in projects and is
commonly value-engineered out or not designed
in the project to start with for Oklahoma projects
• Lack of support of a “new product” from City of
Tulsa Engineering – a City project cannot afford
to be on the cutting edge and risk failure when
using public money
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8. Impediments, continued
• Performance data for a time-tested project constructed in
Oklahoma (not a different part of the country where
climate varies and / or sustainability has been accepted
on a broader level, such as Portland, OR, Chicago, IL or
Austin, TX)
• Public awareness
• Technical specification development
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9. The Plan
• In the summer of 2011 a group started gathering
and meeting at regular intervals
• The group included contractors, academia,
industry concrete educators and organizations,
engineers, architects, builders, inspectors and
code officials from the City of Tulsa, all of whom
have a common personal interest in making
things greener
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10. How we did it
• This project was primarily put together due to the
volunteer efforts of many to make it happen
• After realizing that the “impediments that had to
be addressed” could actually be turned into task
items, the group went to work
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11. Timeline
• 7/27/11 – First meeting:
• Included definition of obstacles / impediments and
concerns and introductions of roles, skills and resources
• Defined the need for a test project to educate the
majority of those involved
• Defined the need to educate the majority of interested
attendees
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12. Timeline
• 8/23/11 – Second meeting:
• Included gathering information on commonly
perceived issues with pervious such as freeze
thaw, durability and maintenance concerns.
• Location of a project site owned by the City of
Tulsa underway
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13. Timeline
• 10/3/11 – Site visit to Twin Cities and GCC Mid-
Continent, two ready-mixed concrete plants in
Tulsa with pervious slabs that had been placed
in the Tulsa area for 5+ years
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16. Timeline
• 11/29/11 – City of Tulsa site chosen, percolation
test results review, performance spec
development.
3 bores taken - .5” to 1.42” / hour percolation rate
8.5” asphalt over 6” agg base, dark gray silty sand with gravel, fill
• 1/20/12 and 2/9/12 – Meetings to coordinate
upcoming certification seminar and
demonstration pour
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19. Timeline
• 3/6/12 – PC Certification seminar by the National Ready
Mixed Concrete Association (NRMCA); reduced rates
offered
• 20 people certified as pervious Technicians = 1,000%
increase of pervious Technicians in Oklahoma.
• Still need to get more contractors with experience in
Installer and Craftsman levels
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20. Timeline
• 3/7/12 – Demonstration pour
• Technical specifications and pervious concrete consultation by the
South Central Cement Promotion Association, OMRCA and NRMCA
• 5 slabs from 5 different ready-mix companies, all placed by Cantera
Concrete
• Slab materials, labor and time donated by Arrow Concrete, Dolese
Brothers Company, GCC-Mid-Continent Concrete, Twin Cities
Ready Mix Concrete, and Eagle Redi-Mix
• Subbase materials donated by Greenhill Materials
• Excavation of subbase and subbase placed by City of Tulsa
• TV and Radio Station Media present
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21. Details on pour
• 100’ x 12’ total area
• 2,000 SF additional draining onto pervious area
• Each of the 5 slabs were 20’ wide by 12’ wide
• ¾” wide HDPE resin lumber expansion joints between
each slab
• ¾” wide x 1- ¾” deep tooled joint was cut at middle (10’)
of each of the 5 slabs
• 18” of washed #57 rock subbase
• 5- ½” thick pervious over rock subbase
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38. One week later – concrete truck flowing water
on slabs
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39. Testing
• Infiltration testing per ASTM C1701/C170M-09
currently being conducted every quarter by
Professor Jason Vogel and his graduate
students with Oklahoma State University (OSU)
• Metal rings were made by OSU
• Single vs. double ring testing
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42. Step Three:
Recording the time it takes a documented amount of water to
flow through the slab, keeping ½ nch of water head during
pour. 42
43. Alternate method of
testing – double ring
infiltration test
A non-typical pervious pavement test that
was tried to compare the ASTM standard
with a typical method used for soil
infiltration.
By utilizing the second ring, we were
attempting to ensure that the middle ring
is only showing the vertical movement of
the water.
In general, our results indicated that there
was no detectable difference unless the
flow was pretty low (less than 300 in/hr or
so). Also note that we only tried this one
time, so these results are very limited.
While the double-ring method measures
infiltration only, the standard single ring
method is meant to be used as a
consistent, repeatable measure of
determining if the pavement is clogged.
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45. Testing
• Acceptable range is 200-1800 inches per hour
• As of the 5th quarterly test conducted in March
2013, a year after the pour, all but one slab is
well within or above range!
• SUCCESS
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46. What’s Next?
• First City of Tulsa project to use pervious concrete starts
construction April of 2013
• Tulsa Fire Department Safety Training Center, located
on the Tulsa Community College (TCC) northeast
campus
• Pervious planned around drill tower, class A burn unit
pad and winding sidewalk connection to TCC
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47. The group
• Special thanks to everyone who helped make
this pilot project an ongoing success!
• The group included:
o Concrete contractors
o Ready-mix concrete suppliers
o National and Oklahoma Ready Mixed Concrete Association
o South Central Cement Promotion Association – part of the
Portland Cement Association
o Oklahoma State University (OSU) staff
o City of Tulsa engineers and architects
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