Performance of Pervious Concrete Pavements Marty Wanielista, Manoj Chopra, Matt Offenberg Joshua Spe

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Performance of Pervious Concrete Pavements Marty
Wanielista, Manoj Chopra, Matt Offenberg Joshua
Spence and Craig Ballock

• Stormwater Management Academy
• University of Central Florida
• Orlando, FL 32816
• wanielis_at_mail.ucf.edu

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Outline of Presentation

• Overview
• Background and Current State
• Objectives of this On-going Project
• Research Plan
• Progress to Date
• UCF Test Site
• Field Tests
• Discussion

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Overview

• Pervious or No-fines Concrete mixture of coarse
  aggregate, Portland Cement, admixtures and water
• Increased Porosity due to limited fines and
  15-20 air voids
• Strong need for Current and Updated Assessment of
  Pervious Pavements due to new regulations pending
  for Stormwater Management

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Overview

• Issues to be addressed
• Design Section
• Construction Methods
• Acceptance Criteria
• Infiltration Rate Performance
• Credit for Replacement of Impervious Area
• Our research will initially address
• Design Section
• Infiltration Rate Performance
• Credit for Replacement of Impervious Areas

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Background and Current State

• Replacement of Impervious Areas with Properly
  Designed and Constructed Pervious Paving Surfaces
  is Desirable
• Treating pervious concrete as a system with
  pavement and sub soil
• ACI Committee 522 has been formed to develop
  Guidelines for the use of Portland Cement
  Pervious Concrete

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Historical and Literature Review

• PC Pervious Pavements have been used for past 20
  years in Areas of Lower Traffic Loads (parking
  lots, shoulders, airport taxiways, some state and
  local roads).
• Must have suitable
• Subsoil Conditions
• Groundwater Locations

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Historical and Literature Review

• Field et al (1982) Water Resources Bulletin
  detailed information on PP.
• Florida Concrete and Products Association (FCPA)
  Portland Cement Pervious Pavement Manual (No.
  605)
• EPA (1999) Stormwater Technology Fact Sheet on
  Porous Pavements
• Several recent articles from USC and Purdue, as
  well as UK, Japan and China.

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FDOT Interests

• Need for a permit, or credit (partial or total)
  for substituting pervious surfaces
• Based on Volume of water that can be Stored and
  allowed to Replenish the Aquifer
• Want answers to
• What is design materials, dimensions, GWT?
• What are proper construction methods?
• What is the infiltration rate for the system?

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Advantages and Disadvantages(EPA, 1999)

• Advantages -
• Recharge to Local Aquifer
• Water budget retention and pollution removal
• Less need for Storm Sewers
• Disadvantages
• Lack of Construction Experience and Expertise
• Clogging
• Cold Weather Problems

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Construction Specifications

• Specifications for contractor certification,
  materials and mix design, construction practices,
  and post construction care
• Sources from EPA, California-Nevada Cement
  Promotions Council PC Specs, and PCI Systems,
  LLC. PC Specs

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Construction Specifications

• Appropriate mix proportions
• /- 5 lbs/CF of design unit weight
• Discrepancies are generally related to water
  content
• Too much water reject load

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Construction Specifications

• Concrete should be stricken off ¼ to ½ of an inch
  about the form boards and compacted to level
• Compaction roll with a 10-inch schedule 40
  steel pipe
• Curing Time pavement should be covered a
  minimum of 7 days

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Construction Specifications

• Limit frequency of heavy traffic e.g.
  construction vehicles, garbage trucks, etc.
• Remove or Limit sources of sediment
• Signage such as ADOPT A LOT
• Curbing should be used to direct infiltrating
  water downward and to prevent erosion at the
  edges of pervious concrete slabs.

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Proposed Design Section (Preliminary)
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Design and Construction Specifications

• Cities of Stuart, Zephyr Hills, Winter Park, and
  Titusville and the Counties of Citrus, Hernando,
  Pasco, and Hillsborough have adopted
  specifications.
• Credit is being determined for use by other
  Cities and WMDs.
• A goal is to have 24 cities and counties with
  pervious concrete code language for pervious
  concrete.
• Contractor Certification will be an Important
  Factor
• Soil Preparation, Curbing, Field Infiltration
  Tests and Inspections will be Important.

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How are Pervious Systems Working?

• Develop New Embedded Single Ring Test Method to
  Measure Infiltration rates
• Laboratory Testing Build Two Test Cells at the
  UCF Stormwater Laboratory Site and a Control
  Chamber
• Field Testing Four field sites in Central
  Florida and one in Tallahassee

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Preparation of Test Cells

• Stormwater Laboratory Field Sites
• Two 6 ft.x 6ft. x 4 ft. deep Chambers
• 5 inch thick pervious concrete pavement
• One cell has a reservoir of 3/8 inch coarse
  aggregate to increase storage
• Soils were Sandy (Type A hydrological) compacted
  in 8 inch lifts to 92 Standard Proctor to about
  104 lb/ft3

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Development of Embedded Single Ring Infiltrometer

• Double Ring Infiltrometer on the surface of
  Pervious Pavement not Suitable due to Preferred
  Lateral Migration of Water
• Led to Concept of Single Embedded Infiltrometer
• Depth of Embedment is an Important Parameter
  (Initial Assumption 14 inches including the 6
  inches of pavement)
• 12 inch Diameter (11-5/8 ID) with 11-Guage Steel

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Embedded Single Ring Infiltrometer
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Embedded Single Ring Infiltrometer

• Advantages
• One dimensional flow (no horizontal flow between
  pavement and soil)
• Representative of site existing conditions
  assuming same soil types,
• and concrete conditions.

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Results at Test Cells

• Using ASTM D3385-03 (Double Ring) procedure
  adapted to embedded Single Ring
• Initial Double Ring Tests on Bare Subsoil before
  Concrete Placement have yielded infiltration rate
  of 2.6 in/hr
• Without compaction, the rate for the soil was
  12-20 in/hr

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Results of UCF Embedded Ring Tests


System or concrete core plus soil infiltration
rates
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Preliminary Observations from UCF Test Chambers

• Pervious Concrete Pavement and Subsoil System
  displays Infiltration Rates nearly equal to
  Subsoil Alone
• Infiltration rates of the system are greater than
  the minimum rates of 1 in/hr used for the design
  of FDOT retention areas.

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Strength Tests
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Laboratory Control Chamber

• Better Control
• Address issues such as Clogging and Water Table
  Impact
• The Chamber was Filled with Sandy Soils from UCF
  Stormwater Lab. (Type A Hydrologic Group )
• Filled in 8 lifts to 92 Standard Proctor

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Laboratory Control Chamber
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Laboratory Control Chamber
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Field Site Reconnaissance

• Vet Office in Sanford
• FCPA Office in Orlando
• Sunray StoreAway Lake Mary
• Strang Communications Lake Mary
• FDEP Office - Tallahassee

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Field Testing Progress

• Six cores at Sunray Storaway, Three at Strang
  Communications, Three at FCPA, Six in
  Tallahassee, and Three at Murphy Vet Clinic.
• Field infiltration tests completed at all
  locations
• Laboratory tests using Control Chamber on-going

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Field Testing Process

• 12-in diameter cores
• Run field tests
• Collect soil samples
• Lab work on soil samples
• Lab test on core infiltration rates

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Field Test Results
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Field Test Results
Age of concrete varies from 10 to 20 years
(except for Site 4 Area 1, which is 1 yr).
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Conclusions

• Proper construction is important (water in mix,
  curing) Certification program is needed.
• Specifications need to be followed for design and
  construction Good design practices (curbing,
  pavement thickness).
• Pavement and Subsoil must be treated as a SYSTEM.

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Conclusions

• Infiltration rates are comparable to Stormwater
  Retention Ponds.
• Water storage is directly proportional to the
  porosity and the depth to the water table.
  Modeling efforts currently underway

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Thank You!For additional informationPlease see
www.stormwater.ucf.eduor call 407.823.4143Quest
ions?