Pervious Concrete Applications and Stormwater Management John Kevern Ph.D., LEED AP Louisiana Transportation Conference Baton Rouge 1/10/11
1/20/2011:1 Overview • Pervious Concrete Background • Design Considerations • Typical Construction Operations • Operation and Maintenance Considerations • Applications
1/20/2011:2 Low Impact Development
Pre-Development Post-Development Low-Impact Development Urbanization Affects Hydrology
* PCA Hydrology manual How Do Permeable Pavements Work?
Permeable Pavement Aggregate base 40 % voids
Natural Soil Pollution Treatment • About 90% of the surface pollutants are carried off by the first ½-inch to 1-inch of rainfall (first flush) • First flush passes through pavement into soil • Soil filters and treats rainfall • Rainfall is spread over entire parking area (instead of detention pond) Protects Trees
Can pave within the drip line Water and air filters to roots Reduce Urban Heat Islands Urban Heat Islands
• 6 – 12 °F Hotter • More Smog Occurrences • High Level of Ground- Level Ozone • More Frequent Air Quality Alerts • Increased Health Problems • Higher Energy Demand Pavement Design • Infiltration-based BMP • Flat base ideal
Ferguson 2005 Pavement Design
Pooling
French drains Check-dams
Tennis et al. 2004 Full Exfiltration
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Jones 2008 Partial Exfiltration
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Jones 2008 No Exfiltration
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Jones 2008 Mix Design Considerations • Balancing Act – Aggregates, binder, water, admixtures
Aggregate Paste
Traditional Concrete
Aggregate Aggregate Paste Pervious Voids Concrete
1/20/2011:15 Air-entrained paste Construction - Excavation
PCC PCPC
Do not compact subbase too much, needs to be permeable Construction - Excavation
PCC
PCPC “bath tub” Construction – Aggregate base
But, compact the base enough Typical Concrete Placement
“Pile and Rake” method Typical Concrete Placement Concrete Finishing
1/20/2011:21 Construction – Jointing
Every 20 feet or match with existing Construction – Concrete Curing
Cure 7-days minimum Operation and Maintenance • All permeable pavements, including Pervious Concrete, are filters • Filters remove particles • Related to size of hole in filter, size of filtered particle, amount of particles, velocity of fluid
1/20/2011:24 Operation and Maintenance
City of Olympia, WA
1/20/2011:25 Operation and Maintenance
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City of Olympia, WA Maintenance Cycles Permeability (in./hr) Permeability
1/20/2011:27 Ferguson 2005 Pervious Concrete Applications • Parking Areas • Driveways • Sidewalks • Roadways •Overlays • Swales & Ditches • Erosion Control • Slope Protection • Load-bearing Walls Pervious Concrete – City Sidewalk
• Year: 2000 • Owner: City of Olympia, WA • 1500 lineal feet of sidewalk • Sub-grade: native soil was permeable enough • Savings: $110,000 - land acquisition for detention ponds unnecessary University of Tennessee-Chattanooga Finley Stadium
Water collected and used for stadium irrigation Legacy Trail, Lexington, KY
1/20/2011:31 Pervious Concrete – Storage Lot • Shelter Systems, Ltd. (Westminster, MD) • Placed 2004 • Wet Freeze (90 cycles/yr) • 8 ac. of pavement saved $400,000 in underground drainage and eliminated 1.5 ac. detention pond • 30-40 heavily loaded trucks per day • Flows 80 inches/hour Stained pervious at Edgewater Park, Minneapolis Overlay, Albertville, MN
1/20/2011:34 Ft. Riley playground
1/20/2011:35 Seatac, WA
1/20/2011:36 Stamped and stained
*Not a recommended location Retaining Wall “Weap block” Pervious Stormwater Summary • Permeable pavements are both BMPs, maintenance will be required (same as any other BMP or pavement) • The amount of maintenance will be site specific, but generally low if protected initially • Use good design, guidance, specifications, and an experienced contractor • Cure it • Success!
1/20/2011:39 Questions Contact Information: John T. Kevern, Ph.D., E.I.T., LEEP AP Assistant Professor of Civil Engineering 370H Flarsheim Hall, 5100 Rockhill Rd. University of Missouri – Kansas City Kansas City, MO 64110 Phone: 816-235-5977 Fax: 816-235-1260 Email: [email protected]