Basics Of Permeable Pavements
Basics of Permeable PavementsSponsored by:Presented by:Rick Crooks
Outline and Learning Objectives Why use permeable pavement? Understand the basic components of the three mostpopular permeable pavement systems:Porous AsphaltPervious ConcretePermeable Interlocking Pavers Understand available system information sources Review construction sequencing for each pavement Review maintenance requirements
Why Permeable Pavement? Part of BMP mix, supports LID Conserves space: a functional pavementand a stormwater management facility 100% runoff reduction for high frequencystorms, can help meet Ecology’s flowcontrol requirement.
Why Permeable Pavement? (cont.) Reduce retention/detention, drainagefees Together with subgrade soil, permeablepavement systems can help filter andreduce pollution from stormwater. Increase groundwater recharge
Determining Subgrade Soil Infiltration Soil maps and soil classificationsystems (NRCS, USCS) Conduct on-site infiltrationtests Use lowest (conservative)values for preliminary design.
Subgrade Infiltration Use site tests for accurate information Frequency and location based on geotechnicalrequirements (consult engineer)Test areaMultiple test holes
Handling sloped sitesDepending on the slope of the project, use checkdams to allow runoff to infiltrate into sub-soil.
Porous Asphalt Defined as full depthporous material – allmaterials in the roadsection are permeable. Historically used as porousfriction course (PFC)overlay to reducehighway spray andminimizes traffic noise. Limited use on localresidential projects, moretypical on municipalstreets.
Arizona SR-87Slide courtesy Mark Palmer, City of Puyallup
Typical Porous Asphalt Cross-SectionSlide courtesy Mark Palmer, City of Puyallup
Materials and Specifications HMA (hot mix asphalt) complies with NAPA specifications forporous applications (polymer additive, 6%-9% asphalt cementbinder). Use fibers and anti-stripping agents in binder toreduce drain-down potential. Aggregate for wearing course is typically 1/4” to 3/8”, thoughlarger gradations have been used successfully. Choker course gradation depends on reservoir coursegradation but is typically 3/4” to 1”. Some projects areeliminating (or minimizing) the choker course. Reservoir aggregate is 1” to 2” gradation (WSDOT Section 903.9(2) permeable ballast). All aggregates are durable, crushed and clean with norounded rock (90-100% fractured face)
Base and Sub-base Aggregates Choker course –well-graded, crushedaggregates (no fines). Reservoir course –Larger crushed aggregates(no fines).
Industry publication National Asphalt PavementAssociation (NAPA) Order number:IS-131www.asphaltpaving.org
Porous Asphalt Construction SequenceSlide courtesy Mark Palmer, City of Puyallup
Porous Asphalt Construction SequenceSlide courtesy Mark Palmer, City of Puyallup
Examples ofPorous AsphaltInstallations
Pervious Concrete ‘No fines’ concretecreates void structurethat allowing for quickdrainage of water. Rigid pavementstructure (differentfrom asphalt or paverswhich are flexiblepavement systems)Photo from www.perviouspavement.org
Typical Pervious Concrete Cross-Sectionfrom Stormwater Management Academy, UCF (2007)
Materials and Specifications Rigid pavement typically requires less base aggregatethan other systems for structure. Contractor certification and educational programshelp promote proper installations. Differences from standard concrete:– stiff mix so no slump or strength testing– cannot be pumped– compact in place with vibratory roller– cover with plastic while curing
Industry Resources National Ready Mixed ConcreteAssociationwww.perviouspavement.org Puget Sound Concrete SpecificationCouncilwww.theconcretecouncil.org Portland Cement Associationwww.cement.org“Pervious Concrete Pavements,”product code EB302
Pervious Concrete Construction Sequencefrom www.perviouspavement.org
Examples of Pervious Concrete Projects
Examples of Pervious Concrete Projects
Examples of Pervious Concrete Projects
Permeable Interlocking ConcretePavements (“PICP”) Unlike other systems, the paving stones thatcomprise the wearing surface of the pavement arenot permeable. Permeability is achieved through openings in thepavers or the joint spaces between the blocks. Structurally, PICP is a flexible pavement (like asphalt)
PICP Cross-Section Permeable paver wearingcourse No. 8 aggregate joint fill No. 8 aggregate bedding No. 57 ‘choke’ course No. 2 reservoir course or‘permeable ballast’ Geotextile (if required)
Types of PICP
Infiltration Rates --Surface, Joints & Bedding Infiltration rate of stone inopenings: 300 to 1200 in./hr Open surface area: varies withpaver design/pattern, typicallyfrom 8% to 18%Initial surface infiltration calculation:1,000 in/hr x 12% open area 120 in/hr
Industry publication Interlocking ConcretePavement Institute (ICPI)www.icpi.org
ConstructionNo. 57No. 2
PICP Installation During excavation, do not compact native soil Compacted soil is 30% to 90% less permeablethan un-compacted soil
Keep delivery trucks off of native soil
Spreading Base Material
Final grading of base material
Compacting base material
Screeding No. 8 stone over No. 57 base
Mechanical placement
Mechanical InstallationMechanical installation of PICP can decreaseconstruction time 20-80% over manual installationManual paver installation:1,000 – 2,000 sq. ft. per man per dayMechanical paver installation:3,000 – 10,000 sq. ft. per machine per day
Edge paverscut andplaced,thencompacted
Compact before sweeping in aggregateCompaction before filling openings
ndFilling the openings with No. 8stone, final compaction
Excess stones removed,then final compaction
Keep sedimentaway from the permeable pavement
Partial Exfiltration Design Option When subgradeinfiltration rates arelow (less than 0.25in/hr, consider‘partial exfiltration’design Uses perforatedpipe ‘under-drainsto route excesswater to outfallNote: Full flow control credit is notallowed when underdrain systemsare utilized.
Design DetailsOverflow drainDrain to grass swale
MaintenanceAnnually: overall system performance inspection,check observation well , inspect after majorstorm, vacuum surface (once, twice, or more)to ensure optimum design life performanceMaintenance checklist (specific to each project)Model maintenance agreementMonitor adjacent uses
Inspection ChecklistVacuum surface1 to 2 times annually, adjustfor sediment loadingReplenish aggregate in PICP jointsAs neededInspect vegetation surroundingpavement perimeter for cover &stabilityAnnually, repair/replant asneededCheck drain outfalls for free flowof waterAnnually and/or after a majorstorm event
New Maintenance DocumentA new O & Mdocument isavailable fromEcology ipal/LID/TRAINING/OperationsAndMaintenance.html
Maintenance
Restoration Maintenance
Other products availableGrid pavement systemsusing concrete or othermaterials
Thank You !Rick CrooksMutual Materials Companyrcrooks@mutualmaterials.comDirect line: (425) 452-2344
porous applications (polymer additive, 6%-9% asphalt cement binder). Use fibers and anti-stripping agents in binder to reduce drain-down potential. Aggregate for wearing course is typically 1/4" to 3/8", though larger gradations have been used successfully. Choker course gradation depends on reservoir course
Key Words: permeable interlocking concrete pavement. permeable pavement design. permeable pavement hydrologic and structural design. permeable pavement construction. permeable pavement maintenance. 1. Chapter 1 - Overview . Since 2009, PICP use in the United States has grown 15% to 20% annually due to national,
Permeable Concrete Pavements Transportation Research Board Webinar 2:00 PM - 3:30 PM . Thursday, March 9, 2017 . Sam Tyson, P.E. Concrete Pavement Engineer . FHWA Office of Asset Management, Pavements, and Construction . Permeable Concrete Pavements . Typically higher cost
6—Factors Affecting the Selection of Permeable Formwork . 27 Costs and Cost-Benefits of Using Permeable Formwork . 27 Misuse of Permeable Formwork . 29 Difficulties in Handling . 29 7—Long-Term Testing of Surfaces Formed with Permeable
P-3 Permeable pavers (PP) Other variations of permeable pavement that are DDOE-approved permeable pavement surface materials, such as synthetic turf systems with reservoir layer, are also encompassed in this section. Permeable pavement systems are not typically designed to provide stormwater detention of
VA DEQ STORMWATER DESIGN SPECIFICATION NO. 7 PERMEABLE PAVEMENT. Version 2.0, January 1, 2013 Page 1 of 33. VIRGINIA DEQ STORMWATER . . and permeable grid pavers and interlocking concrete pavers. While the specific design may vary, all permeable pavements have a similar structure, . Cost . 5. 2.00 to 6.50/sq. ft. 0.50 to 1.00/ sq. ft.
PERMEABLE PAVEMENT COMPONENTS The essential components of a permeable pavement are shown in Figure 1. The elements of the pavement, which are described in detail in subsequent sections of this manual, comprise: 1. A surfacing of permeable pavers design to permit the rapid infiltration of rainfall (see Sections 7.1.1 and 9.1). Typically, the .
452 Surface infiltration rate of permeable pavements only Zinc has been identified as having a statistically significant difference between infiltrate and runoff. 22.1 Introduction Permeable pavement is an alterna
This Tech Brief presents an overview of two types of permeable concrete pavement systems and their use. Information is provided on the structural and hydrological design, factors for successful construction and maintenance, and the performance of these systems. BACKGROUND Permeable pavements originated in Europe some 45 years ago.
