Presented to: Pervious in Paradise - San Diego Presented by: David Liguori, Bay Area Pervious Concrete

1. Pervious Concrete and Rebar
David Liguori
Pervious in Paradise 2014
Technical Services Division

2. Don’t you Love it when someone asks….
BAPC Technical
Services Division

3. • You put rebar in pervious concrete, right?
Don’t you Love it when someone asks….
BAPC Technical
Services Division

4. • You can put rebar in pervious concrete, right?
• Don’t All high quality slabs have rebar?
Don’t you Love it when someone asks….
BAPC Technical
Services Division

5. • You can put rebar in pervious concrete, right?
• Don’t All high quality slabs have rebar?
• What will stop the slab from falling apart
without rebar?
Don’t you Love it when someone asks….
BAPC Technical
Services Division

6. • You can put rebar in pervious concrete, right?
• Don’t All high quality slabs have rebar?
• What will stop the slab from falling apart
without rebar?
• You need rebar to prevent vertical
displacement, don’t you?
Don’t you Love it when someone asks….
BAPC Technical
Services Division

7. Function of rebar in slabs on grade (SOG)
• Crack control
• Minimize vertical displacement
Rebar in SOG is considered secondary reinforcement as it
does not increase the compressive or flexural strength of the
slab
BAPC Technical
Services Division

11. BAPC Technical
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15. STRUCTURAL INTEGRITY OF EPOXY-COATED BARS
*Quality and consolidation of the surrounding concrete
had an important influence on the corrosion of epoxy-
coated bars. More corrosion was observed at surfaces
surrounded by less dense, very porous concrete with more
and larger voids.
*CORROSION PERFORMANCE OF EPOXY-COATED REINFORCEMENT–MACROCELL TESTS CORROSION PERFORMANCE
OF EPOXY-COATED REINFORCEMENT–MACROCELL TESTS by Khaled Z. Kahhaleh, Enrique Vaca-Cortés, James O. Jirsa,
Harovel G. Wheat, and Ramón L. Carrasquillo Texas Dept of Transportation Nov 1998
BAPC Technical
Services Division

17. BAPC Technical
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18. Will pervious concrete flow around rebar?
BAPC Technical
Services Division

19. • Will pervious concrete flow around rebar?
• No, it must be hand packed
BAPC Technical
Services Division

20. • Will pervious concrete flow around rebar?
• No, it must be hand packed
• Is that possible?
BAPC Technical
Services Division

21. • Will pervious concrete flow around rebar?
• No, it must be hand packed
• Is that possible?
• If so is it practical?
BAPC Technical
Services Division

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70x70 ~ 5,000sqft ~ 6,500 lin ft rebar

23. • Will pervious concrete flow around rebar?
• No, it must be hand packed
• Is that possible?
• If so is it practical?
• Is it effective?
BAPC Technical
Services Division

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26. Air pockets due to lack of consolidation around
the bars may actually weaken the slab,
Exactly the opposite of rebars intended
purpose
BAPC Technical
Services Division

27. Successful hand packing around rebar…
• Requires two lifts
• Is highly Labor intensive and time consuming
• Significantly increases the amount of time the
slab is exposed
All of which dramatically increase the cost of the
installation as well as the risk of failure
BAPC Technical
Services Division

29. Getting the concrete
where you need it…
…how many chutes do
you use?
BAPC Technical
Services Division

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32. Is Rebar Even Necessary in SOG ?
• Steel reinforcement actually increases the number of cracks by restraining
shrinkage and creating additional stress forces within the slab.
• ACI 330R-08 Guide for the Design and Construction of Concrete Parking Lots:
“Reinforcing steel is not required or recommended for rigid pavements”
• San Francisco prohibits the use of rebar in city sidewalks
BAPC Technical
Services Division

33. For slabs on grade with a properly prepared subgrade and base, proper
control joint design, proper mix design and section thickness, proper
placement, finishing, and curing… will do more to achieve good
performance from the slab than rebar of any type .
Is Rebar Even Necessary in SOG ?
BAPC Technical
Services Division

34. Is Rebar Necessary
In Pervious Concrete ?
• Less water along with aggregate to aggregate contact means less
shrinkage, and therefore less shrinkage cracks
• Adequate Sub base thickness is critical to performance of any SOG
• Pervious concrete typically has a better prepared, thicker sub base
section, which results in more structural stability
• Aggregate interlock more effective due to course nature of pervious
concrete
BAPC Technical
Services Division

35. Alternative Reinforcement Method;
Macro Fibers
BAPC Technical
Services Division

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Thanks!
Questions?

41. BAPC Technical
Services Division