Permeable Paving
Remake batch 23: rewritten from scratch under the authoring cheatsheet with datasheet constraints; scope boundaries restated against the remade neighbors
Showing changes from Rev 3
to Rev 4
in Permeable Paving.
---
title: Permeable Paving
category: Sitework
−toc_depth: 3
description: >
− When to use: Load-bearing pavement engineered to infiltrate stormwater through or
− between the surface into a reservoir aggregate base and/or native subgrade — pervious
− concrete, porous asphalt, permeable interlocking concrete pavers (PICP), and concrete
− grid pavers — for parking lots, low-to-medium-speed roadways, plazas, driveways, bike
− paths, and loading areas where runoff reduction, water-quality treatment, or groundwater
− recharge is a project goal or regulatory requirement. Covers the full section (surface,
− bedding, reservoir base, geotextile, underdrains, outlet control) and the three
− hydrologic modes: full, partial, and no infiltration.
− Not intended for: dense-graded hot-mix asphalt without permeable voids (use
− [[sync/asphalt-paving]]); conventional portland-cement concrete pavement without pervious
− voids (use [[sync/concrete-paving]]); compacted aggregate surfacing or road base (use
− [[sync/aggregate-base-course]]); detention/retention basins, bioretention cells, swales,
− and underground vaults (use [[sync/stormwater-management-systems]]); geotechnical subgrade
− instrumentation and monitoring below the pavement section (use
− [[sync/geotechnical-instrumentation-and-monitoring]]); and general site grading and
− earthwork that establishes the subgrade elevation.
+ When to use: Load-bearing pavement built to pass stormwater through or between its surface into an open-graded stone reservoir and from there into the native soil, an underdrain, or both, on commercial, institutional, industrial, campus, and multi-family sites: parking lots, drive aisles, service and loading areas, fire lanes and emergency access, plazas, walkways, and overflow parking, wherever the stormwater permit, the land-development ordinance, or the Owner's own runoff goal credits the pavement as a stormwater practice. Covers the four surface systems, pervious concrete, porous asphalt, permeable interlocking concrete pavers, and concrete grid pavers; the hydrologic mode of the section, full, partial, or no infiltration, as the decision every other selection follows from; the bedding, choker, and base courses; the open-graded reservoir and its void ratio; the separation geotextile and the geomembrane liner of a no-infiltration section; the underdrain, its raised outlet, and the drawdown of the reservoir; edge restraints; observation wells and cleanouts; the subgrade infiltration basis and its protection from compaction and sediment through construction; surface infiltration acceptance testing; and turnover of the pavement to the party that will vacuum-sweep it. Read alongside the stormwater management report and the civil grading and paving drawings, which carry the reservoir depth, the underdrain and outlet elevations, the surface grades, and the limits of each pavement cell, and alongside the geotechnical investigation report, which carries the subgrade infiltration rate the hydrologic mode rests on.
+ Not intended for: Conventional dense hot-mix asphalt pavement (see [[sync/asphalt-paving]]); conventional portland cement concrete pavement, curbs, gutters, and sidewalks, including the curb that restrains a paver edge (see [[sync/concrete-paving]]); the dense aggregate base beneath a conventional pavement (see [[sync/aggregate-base-course]]); solid-jointed unit pavers set on a sand or mortar bed that do not pass water, which no standard in this library currently covers; detention and retention basins, bioretention cells, swales, underground storage chambers and vaults, and the outlet structure of a site stormwater facility (see [[sync/stormwater-management-systems]]); the storm sewer, inlets, and manholes the underdrain discharges to (see [[sync/storm-drainage]]); mass excavation, structural fill, and proof rolling of a subgrade that is not an infiltration subgrade (see [[sync/earthwork]]); the AASHTO M 288 property class, certified test reports, and conformance of the geotextile furnished by reference (see [[sync/geosynthetics]]); piezometers, settlement monuments, and other subgrade instruments (see [[sync/geotechnical-instrumentation-and-monitoring]]); markings, striping, and signs on the finished surface (see [[sync/pavement-markings]]); and the hydrologic routing that sets the storage volume and release rate of the reservoir, which is the work of the civil engineer of record and is recorded in the stormwater management report.
---
# Scope {toc}
−## This standard covers the design, materials, construction, and acceptance testing of permeable pavement surfaces that allow stormwater to infiltrate through or between the pavement into a subsurface reservoir aggregate base and/or the native subgrade. {note}
+## This standard governs the materials, construction, testing, and acceptance of a permeable pavement section from the accepted infiltration subgrade or liner upward: the reservoir stone, the choker, base, and bedding courses, the surface course, the underdrain and its outlet within the section, the edge restraints, and the observation and cleanout provisions through which the Owner will maintain it. {note}
−## Four primary surface types are addressed, each sharing the same three-layer logic (surface course, bedding/setting layer, reservoir base) but differing in materials and placement: {note}
+## The four surface systems covered are listed below. Each is a different product placed by a different trade, and each sits on the same open-graded reservoir, so this standard carries one set of articles for the section beneath the surface and a conditional article for each surface. {note}
−- Pervious concrete (PC) — a near-zero-slump portland-cement concrete with interconnected voids, placed and finished by specialty crews.
−- Porous asphalt (PA) — an open-graded asphalt wearing course over an open-graded aggregate reservoir.
−- Permeable interlocking concrete pavers (PICP) — solid concrete units set on washed stone bedding with open, aggregate-filled joints.
−- Concrete grid pavers (CGP) — open-cell concrete frames filled with aggregate or turf, used mainly for fire lanes, emergency access, and overflow parking.
+- Pervious concrete, a no-fines portland cement concrete with a connected void structure, placed and compacted in place without finishing tools
+- Porous asphalt, an open-graded asphalt wearing course with a modified binder, placed and rolled without vibration
+- Permeable interlocking concrete pavers, solid concrete units set on an open-graded bedding course with the water passing through aggregate-filled joints
+- Concrete grid pavers, open-celled concrete units whose cells are filled with aggregate or turf, carrying intermittent loads on fire lanes and overflow parking
−## Three hydrologic modes are recognized and selected from subgrade soil permeability and site constraints: full infiltration (all water enters the subgrade), partial infiltration (underdrains with a raised outlet hold water for infiltration before overflow), and no infiltration (impermeable liner with full underdrain drawdown over impermeable or contaminated subgrades). {note}
+## A permeable pavement is a stormwater facility that is driven on. It is credited in the stormwater permit with a storage volume and an infiltration or release rate, and it is accepted on the surface rate at which water enters it; its service life is set by sediment, not by wheel loads. Every construction rule in this standard follows from one fact: a void that is filled with fines during construction never drains again, and no repair short of removal recovers it. {note}
−## The scope includes the surface course, the bedding or setting layer, the reservoir aggregate base, the optional geotextile separation layer, optional perforated underdrain piping, and overflow/outlet control structures. {note}
+## The following are outside this standard and are governed elsewhere. {note}
−## Governing local stormwater authority criteria control where they are more stringent than this standard.
+- Conventional dense hot-mix asphalt pavement, under [[sync/asphalt-paving]]
+- Conventional concrete pavement, and the cast-in-place or precast curb that restrains a paver edge, under [[sync/concrete-paving]]
+- The dense aggregate base beneath a conventional pavement, under [[sync/aggregate-base-course]]
+- Detention and retention basins, bioretention, swales, underground storage, and the outlet structure of the site stormwater facility, under [[sync/stormwater-management-systems]]
+- The storm sewer, inlets, and manholes the underdrain discharges to, under [[sync/storm-drainage]]
+- Mass excavation to within 12 in. of the reservoir subgrade, structural fill, and the proof rolling of a subgrade beneath a no-infiltration section, under [[sync/earthwork]]
+- The property class, certified test reports, and conformance of the geotextile, under [[sync/geosynthetics]]
+- Subgrade instruments, under [[sync/geotechnical-instrumentation-and-monitoring]]
+- Markings and signs on the finished surface, under [[sync/pavement-markings]]
+- The storage volume, the design storms, and the release rate of the reservoir, which are set by the stormwater permit and the governing stormwater design manual and recorded in the stormwater management report
−## Where a Municipal Separate Storm Sewer System (MS4) NPDES permit, a state stormwater manual, or a local ordinance prescribes a specific best-management-practice (BMP) design standard, that criterion supplements or supersedes the generic requirements here. {note}
+## Solid-jointed unit pavers on a sand or mortar setting bed are a different pavement that passes no water, and no standard in this library currently covers them; a project that uses both places the solid pavers under a project-specific specification and the permeable pavers under this standard. {note}
−## Hydrologic sizing, contributing-area routing, and outlet connection to the site stormwater network shall be coordinated with the project civil engineer and the design shown on the [[sync/stormwater-management-systems]] drawings.
+## The reservoir depth, the underdrain and outlet elevations, the surface grades, and the limits of each pavement cell shall be as shown in the Contract Documents, and the Contractor shall not alter them to suit field conditions without the written direction of the Engineer of Record.
+## Where this standard and the stormwater management report conflict, the report shall govern for the storage volume, the hydrologic mode, the reservoir depth, and the outlet elevations, and this standard shall govern for materials, procedure, testing, and acceptance, unless the Engineer of Record directs otherwise in writing.
+
+## Where the governing stormwater design manual or the stormwater permit sets a requirement more stringent than this standard, the more stringent requirement shall govern.
+
+## The Contractor shall report to the Engineer of Record any condition that prevents the section from being built as drawn, including groundwater, bedrock, or a soil at the subgrade that differs from the geotechnical investigation report, a utility within the reservoir, and an underdrain invert that does not meet the connecting storm sewer.
+
+## The Contractor shall coordinate work under this standard with [[sync/earthwork]] for the excavation above the reservoir subgrade and for the subgrade beneath a no-infiltration section; with [[sync/erosion-and-sediment-control]] for the diversion of runoff around the cell until the contributing area is stabilized; with [[sync/storm-drainage]] for the inlet or manhole the underdrain discharges to and its invert; with [[sync/stormwater-management-systems]] where the reservoir drains to a downstream facility; with [[sync/concrete-paving]] for the curb that restrains a paver edge and the sequence of curb and pavement; with [[sync/geosynthetics]] for the geotextile furnished by reference; with [[sync/landscape-irrigation]] so that no irrigation head discharges onto the permeable surface; and with [[sync/pavement-markings]] for the age and condition of the surface at the time it is marked.
+
# Referenced Standards {toc}
−## Materials, design, construction, and testing shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+## Materials, mixture design, testing, and execution shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## The governing local or state stormwater BMP design manual, where one applies to the project, takes precedence over the generic design criteria in the standards below. {note}
−
| Standard | Title |
|----------|-------|
−| ASCE/T&DI/ICPI 68-18 | Permeable Interlocking Concrete Pavement |
+| ASCE 68 | Permeable Interlocking Concrete Pavement |
+| ACI 522R | Report on Pervious Concrete |
+| ACI 522.1 | Specification for Pervious Concrete Pavement |
| ASTM C936/C936M | Solid Concrete Interlocking Paving Units |
−| ASTM C1781/C1781M | Surface Infiltration Rate of Permeable Unit Pavement Systems |
+| ASTM C1319 | Concrete Grid Paving Units |
+| ASTM C1645/C1645M | Freeze-thaw and De-icing Salt Durability of Solid Concrete Interlocking Paving Units |
+| ASTM C1688/C1688M | Density and Void Content of Freshly Mixed Pervious Concrete |
| ASTM C1701/C1701M | Infiltration Rate of In Place Pervious Concrete |
+| ASTM C1747/C1747M | Determining Potential Resistance to Degradation of Pervious Concrete by Impact and Abrasion |
| ASTM C1754/C1754M | Density and Void Content of Hardened Pervious Concrete |
−| ASTM C1645/C1645M | Freeze-thaw and De-icing Salt Durability of Solid Concrete Interlocking Paving Units |
−| ACI 522R-10 | Report on Pervious Concrete |
−| ACI 522.1-13 | Specification for Pervious Concrete |
+| ASTM C1781/C1781M | Surface Infiltration Rate of Permeable Unit Pavement Systems |
+| ASTM C33/C33M | Concrete Aggregates |
+| ASTM C88/C88M | Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate |
+| ASTM C117 | Materials Finer than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing |
+| ASTM C131/C131M | Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine |
+| ASTM C136/C136M | Sieve Analysis of Fine and Coarse Aggregates |
+| ASTM C150/C150M | Portland Cement |
+| ASTM C595/C595M | Blended Hydraulic Cements |
+| ASTM C260/C260M | Air-Entraining Admixtures for Concrete |
+| ASTM C494/C494M | Chemical Admixtures for Concrete |
+| ASTM C94/C94M | Ready-Mixed Concrete |
+| ASTM D448 | Sizes of Aggregate for Road and Bridge Construction |
+| AASHTO M 43 | Sizes of Aggregate for Road and Bridge Construction |
+| ASTM D5821 | Determining the Percentage of Fractured Particles in Coarse Aggregate |
| ASTM D3385 | Infiltration Rate of Soils in Field Using Double-Ring Infiltrometer |
−| ASTM D7928 | Particle-Size Distribution of Fine-Grained Soils Using the Sedimentation (Hydrometer) Analysis |
−| EPA 832-F-99-023 | Stormwater Best Management Practice: Porous Pavement |
−| NAPA IS 131 | Porous Asphalt Pavement for Parking Lots |
−| AASHTO M 43 | Sizes of Aggregate for Road and Bridge Construction (No. 2, 3, 4, 5, 57, 8, 9 gradations) |
+| ASTM D5084 | Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter |
+| AASHTO M 320 | Performance-Graded Asphalt Binder |
+| AASHTO M 332 | Performance-Graded Asphalt Binder Using Multiple Stress Creep Recovery (MSCR) Test |
+| ASTM D7064/D7064M | Open-Graded Friction Course (OGFC) Mix Design |
+| ASTM D6390 | Determination of Draindown Characteristics in Uncompacted Asphalt Mixtures |
+| ASTM D979/D979M | Sampling Asphalt Mixtures |
+| NAPA IS 131 | Porous Asphalt Pavements for Stormwater Management |
+| AASHTO M 252 | Corrugated Polyethylene Drainage Pipe |
+| AASHTO M 294 | Corrugated Polyethylene Pipe, 300- to 1500-mm (12- to 60-in.) Diameter |
+| ASTM D2729 | Poly(Vinyl Chloride) (PVC) Sewer Pipe and Fittings |
+| ASTM D3034 | Type PSM Poly(Vinyl Chloride) (PVC) Sewer Pipe and Fittings |
+| AASHTO M 288 | Geosynthetic Specification for Highway Applications |
+| GRI GM13 | Test Methods, Test Properties and Testing Frequency for High Density Polyethylene (HDPE) Smooth and Textured Geomembranes |
+| GRI GM17 | Test Methods, Test Properties and Testing Frequency for Linear Low Density Polyethylene (LLDPE) Smooth and Textured Geomembranes |
+| ASTM D7176 | Non-Reinforced Polyvinyl Chloride (PVC) Geomembranes Used in Buried Applications |
+| ASTM D5820 | Pressurized Air Channel Evaluation of Dual Seamed Geomembranes |
# Submittals {toc}
## Action Submittals {toc}
−### The Contractor shall submit the following action submittals for review before commencing work:
+### The Contractor shall submit the following for the Engineer of Record's review before any surface course material, paving unit, aggregate, geotextile, liner, or pipe is delivered to the site:
−- Product data for each surface course, paving unit, bedding aggregate, reservoir aggregate, geotextile, and underdrain pipe.
−- Pervious concrete or porous asphalt mix design with target void content, aggregate gradation, and admixtures.
−- Aggregate gradation reports for bedding, joint-fill, and reservoir stone with washed-stone certification.
−- Shop drawings showing the pavement section, layer thicknesses, slopes, underdrain layout and invert/outlet elevations, edge restraints, and maintenance access locations.
−- Manufacturer data confirming paving-unit compressive strength and, in freeze-thaw climates, freeze-thaw durability.
−- Contractor qualification records (see Quality Assurance).
+- Product data for each paving unit, grid unit, edge restraint, underdrain pipe and fitting, geotextile, liner, observation well, and cleanout, identifying the product standard it is furnished to satisfy
+- Pervious concrete mixture design under ACI 522.1, stating the cementitious materials and content, the aggregate source and gradation, the water-cementitious materials ratio, each admixture and its dosage, the design void content, the design fresh density, and the results of the trial batch
+- Porous asphalt job-mix formula stating the aggregate sources and combined gradation, the binder grade and source, the design binder content, the modifier and fiber and their dosages, the design air void content, and the draindown test result
+- Aggregate test reports for each bedding, joint fill, choker, base, and reservoir source, reporting the gradation per ASTM C136/C136M, the fines per ASTM C117, the fractured particles per ASTM D5821, the Los Angeles abrasion per ASTM C131/C131M, the soundness per ASTM C88/C88M, and the measured void ratio of the reservoir stone
+- Paving unit test reports for compressive strength and absorption per ASTM C936/C936M or ASTM C1319, and freeze-thaw durability per ASTM C1645/C1645M where this standard requires it
+- Shop drawings showing the pavement section for each cell, the thickness of each layer, the reservoir bottom elevation and any terrace or check dam, the liner extent, the underdrain layout with inverts and the outlet elevation, the cleanouts and observation wells, the edge restraints, and the paver laying pattern
+- Geotextile product data and certified test report under [[sync/geosynthetics]] for the separation function
+- Installer qualifications under the Quality Assurance section of this standard
```datasheet
−label: Action Submittals
+label: Action Submittals Required
type: checkbox
options:
− - Product data (surface, units, aggregates, geotextile, underdrain)
− - Mix design (PC/PA) with target void content and gradation
− - Aggregate gradation and washed-stone certification
− - Shop drawings (section, slopes, underdrain, edge restraint, access)
− - Paving-unit strength and freeze-thaw durability data
− - Contractor qualification records
−default: []
+ - "Product data for units, restraints, pipe, geotextile, liner, and access provisions"
+ - "Pervious concrete mixture design with trial batch"
+ - "Porous asphalt job-mix formula with draindown result"
+ - "Aggregate test reports for each layer and source"
+ - "Paving unit strength, absorption, and freeze-thaw reports"
+ - "Shop drawings with section, underdrain, outlet, and access provisions"
+ - "Geotextile product data and certified test report"
+ - "Installer qualifications"
+default: ["Product data for units, restraints, pipe, geotextile, liner, and access provisions", "Aggregate test reports for each layer and source", "Shop drawings with section, underdrain, outlet, and access provisions", "Installer qualifications"]
+constraint: all_of
```
+### No surface course shall be placed until the mixture design or the paving unit submittal for that surface has been reviewed and returned.
+
+### Review of a submittal does not relieve the Contractor of responsibility for compliance with the Contract Documents.
+
## Informational Submittals {toc}
−### The Contractor shall submit the following informational submittals:
+### The Contractor shall submit the following for the record as each becomes available:
−- Subgrade infiltration test results (double-ring infiltrometer per ASTM D3385) confirming the design hydrologic mode.
−- Mock-up acceptance record for the demonstration panel.
−- Construction-phase sediment-protection plan for the pavement area.
+- The subgrade infiltration test report, identifying the method, the test locations and depths relative to the reservoir bottom, the measured rates, and the design rate derived from them
+- The construction sequence and sediment protection plan for each pavement cell, showing the diversion of runoff, the equipment routes, and the stage at which the surface course is placed
+- The subgrade acceptance record for each cell, showing the date of the hold-point release and the date the geotextile or reservoir stone was placed
+- The mock-up acceptance record
+- Aggregate delivery tickets for each layer, identified to the source and the test report
+- Pervious concrete delivery tickets showing the batch time and the time of discharge, and porous asphalt delivery records showing the mixture temperature at delivery
```datasheet
−label: Informational Submittals
+label: Informational Submittals Required
type: checkbox
options:
− - Subgrade infiltration test results (ASTM D3385)
− - Mock-up acceptance record
− - Construction-phase sediment-protection plan
−default: []
+ - "Subgrade infiltration test report"
+ - "Construction sequence and sediment protection plan"
+ - "Subgrade acceptance record per cell"
+ - "Mock-up acceptance record"
+ - "Aggregate delivery tickets"
+ - "Surface course delivery tickets and temperature records"
+default: ["Subgrade infiltration test report", "Construction sequence and sediment protection plan", "Subgrade acceptance record per cell"]
+constraint: all_of
```
## Closeout Submittals {toc}
−### The Contractor shall submit the following closeout submittals before final acceptance:
+### The Contractor shall deliver the following before substantial completion:
−- Surface infiltration acceptance test reports (ASTM C1701 for PC, ASTM C1781 for PICP/CGP).
−- Pervious concrete void-content test reports (ASTM C1754) where pervious concrete is used.
−- Record drawings showing as-built layer thicknesses, underdrain inverts, and maintenance-access locations.
−- Operation and maintenance manual including the required vacuum-sweeping schedule.
+- Surface infiltration test reports for every test location, passing and failing, identified to the cell and the location
+- Pervious concrete fresh density records and core reports for thickness, density, and void content
+- The drawdown observation record for each cell with an observation well
+- Record drawings showing the as-built layer thicknesses, the reservoir bottom elevation, the underdrain inverts and the outlet elevation, and the location of every cleanout and observation well
+- The operation and maintenance manual required by the Maintenance Turnover section of this standard
+- The maintenance agreement or covenant the stormwater permit requires for the pavement, executed and recorded where recording is required
+- Warranty documentation under this standard
+- Receipt for the attic stock delivered under this standard
```datasheet
−label: Closeout Submittals
+label: Closeout Submittals Required
type: checkbox
options:
− - Surface infiltration acceptance reports (C1701 / C1781)
− - Void-content test reports (C1754, pervious concrete)
− - Record drawings (thicknesses, inverts, access)
− - Operation and maintenance manual
−default: []
+ - "Surface infiltration test reports, passing and failing"
+ - "Pervious concrete density and core reports"
+ - "Drawdown observation record"
+ - "Record drawings with as-built layers, inverts, and access locations"
+ - "Operation and maintenance manual"
+ - "Recorded maintenance agreement or covenant"
+ - "Warranty documentation"
+ - "Attic stock receipt"
+default: ["Surface infiltration test reports, passing and failing", "Record drawings with as-built layers, inverts, and access locations", "Operation and maintenance manual", "Warranty documentation"]
+constraint: all_of
```
# Quality Assurance {toc}
−## Pervious concrete shall be placed by a crew under the direct supervision of a technician holding current NRMCA Pervious Concrete Contractor Certification (PCCP) or a documented equivalent.
+## Installer Qualifications {toc}
−## Pervious concrete is placed and finished without traditional finishing tools and at near-zero slump. {note}
+### Pervious concrete shall be placed by a crew qualified on the basis indicated in the datasheet.
−## Troweling, vibrating, and over-rolling the pervious concrete surface shall not be done.
+```datasheet
+label: Pervious Concrete Installer Qualification Basis
+type: radio
+options:
+ - "A technician holding a current pervious concrete craftsman or installer certification from a national ready-mixed concrete industry program present at every placement"
+ - "Documented completion of not fewer than three pervious concrete placements of comparable area within the preceding five years"
+default: "A technician holding a current pervious concrete craftsman or installer certification from a national ready-mixed concrete industry program present at every placement"
+```
−## Porous asphalt shall be placed by a contractor with documented experience producing and placing open-graded asphalt wearing courses.
+### Pervious concrete is placed at near-zero slump, struck and compacted in minutes, and covered before it dries, and none of that resembles conventional flatwork; the certification program tests the crew on exactly those steps, while the experience basis admits a crew that has learned them on earlier work and depends on the Engineer of Record checking the references. {note}
−## PICP shall be installed by a contractor with documented experience installing permeable interlocking concrete pavement of comparable scale, or holding an ICPI PICP Specialist credential.
+### Permeable interlocking concrete pavers shall be installed by a contractor qualified on the basis indicated in the datasheet.
−## The Contractor shall construct a demonstration mock-up of each surface type, of an area agreed with the Engineer, on the actual reservoir base before full production.
+```datasheet
+label: Paver Installer Qualification Basis
+type: radio
+options:
+ - "A foreman holding a current permeable interlocking concrete pavement installer certification from the concrete paver industry association present at every placement"
+ - "Documented completion of not fewer than three permeable interlocking concrete pavement installations of comparable area within the preceding five years"
+```
−## The mock-up establishes the accepted appearance, surface texture, joint fill, and infiltration performance for the work. {note}
+### Porous asphalt shall be produced by a plant that has produced an open-graded mixture within the preceding two years and placed by a crew that has placed porous asphalt or an open-graded friction course on not fewer than two projects.
−## The mock-up shall remain in place as the standard of comparison until the work is accepted.
+### The installing foreman for each surface type shall be present whenever that surface is being placed.
−## The mock-up may be incorporated into the permanent work if it meets all acceptance criteria.
+## Testing Agency {toc}
−### Contractor Qualification
+### Acceptance testing for surface infiltration, pervious concrete density and void content, and aggregate conformance shall be performed by a testing agency retained as indicated in the datasheet.
```datasheet
−label: Pervious concrete contractor qualification
+label: Permeable Pavement Testing Agency Retained By
type: radio
options:
− - NRMCA PCCP certified supervisor on site
− - Documented equivalent pervious concrete experience
− - Not applicable (no pervious concrete on project)
−default: NRMCA PCCP certified supervisor on site
+ - "Owner"
+ - "Contractor, with results reported directly to the Owner"
+default: "Owner"
```
−```datasheet
−label: PICP installer qualification
−type: radio
−options:
− - ICPI PICP Specialist credential
− - Documented comparable PICP installation experience
− - Not applicable (no PICP on project)
−default: Documented comparable PICP installation experience
−```
+### The subgrade infiltration test shall be performed by or under the supervision of the geotechnical engineer of record.
−# Environmental and Service Conditions {toc}
+### The producer's quality-control tests do not substitute for the acceptance tests of this standard, and acceptance tests shall be taken at locations the testing agency selects.
−## Surface Type Selection {toc}
+## Pre-Installation Conference {toc}
−## Surface type is selected from traffic loading, aesthetics, freeze-thaw exposure, and budget; all four types share the same reservoir-base design approach, so the choice is driven by the surface course rather than the storage layer. {note}
+### Before the reservoir subgrade of the first cell is excavated, the Contractor shall convene a conference attended by the Contractor's superintendent, the earthwork subcontractor, the installer of each surface type, the aggregate supplier, the testing agency, the geotechnical engineer of record, the civil engineer of record, and the Authority Having Jurisdiction's inspector where the stormwater permit requires attendance.
−## Concrete grid pavers are a niche variant used primarily for fire lanes, emergency access, and overflow parking, where load-bearing capacity is needed only intermittently and a vegetated or aggregate-filled surface is acceptable. {note}
+### The conference shall review the construction sequence relative to stabilization of the contributing area, the protection of the subgrade from compaction and sediment, the hold points, the aggregate sources and their delivery and stockpiling, the mixture designs, the mock-up, the surface infiltration acceptance test and its frequency, the procedure for a failing test, and the turnover cleaning.
−## The permeable pavement surface type shall be specified, suited to the loading and use it will serve.
+## Mock-Up {toc}
+### A mock-up of each surface type shall be constructed as indicated in the datasheet, on the project reservoir section, with the project materials, equipment, and crew.
+
```datasheet
−label: Permeable pavement surface type
+label: Surface Course Mock-Up
type: radio
options:
− - Pervious concrete (PC)
− - Porous asphalt (PA)
− - Permeable interlocking concrete pavers (PICP)
− - Concrete grid pavers (CGP)
−default: Permeable interlocking concrete pavers (PICP)
+ - "Required for each surface type"
+ - "Not required"
+default: "Required for each surface type"
```
−## The traffic loading class shall be specified, and it shall govern the permeable pavement surface type and structural design selected.
+### Where a mock-up is required, it shall be not less than 225 ft² for pervious concrete and porous asphalt and not less than 100 ft² for pavers, and it shall be tested for surface infiltration by the method and at the rate this standard requires before any production surface is placed.
+### The mock-up shall establish the surface texture, the joint fill level, the compaction equipment and passes, and, for pervious concrete, the placement rate and the curing procedure, and the accepted mock-up shall be the standard of comparison for the production work.
+
+### A mock-up that meets every requirement of this standard may remain as part of the work, and a mock-up that does not shall be removed and replaced at the Contractor's expense.
+
+## Inspection Hold Points {toc}
+
+### The Contractor shall give the Engineer of Record and the Authority Having Jurisdiction's inspector not less than 24 hours' notice before each hold point listed below, and shall not proceed past a hold point until the inspection has been performed and released in writing:
+
+- The excavated reservoir subgrade of each cell, after the subgrade infiltration test where one is required on the finished subgrade, and before any geotextile, liner, or stone is placed
+- The liner, after seam testing and before the cushion geotextile and stone are placed over it
+- The underdrain, with its inverts surveyed, before it is covered with stone
+- The completed reservoir and choker or base course, before the bedding or the surface course is placed
+- The surface infiltration test at each location
+
+### Where an inspection is not performed within 24 hours of the scheduled time through no fault of the Contractor, the Contractor may proceed after notifying the Engineer of Record in writing, and the Owner shall bear the cost of any later uncovering required to inspect that work.
+
+# Design Basis and Site Conditions {toc}
+
+## Surface Type {toc}
+
+### The permeable pavement surface type shall be as indicated in the datasheet.
+
```datasheet
−label: Traffic loading class
−type: radio
+label: Permeable Pavement Surface Type
+type: select
options:
− - Pedestrian / plaza only
− - Passenger vehicles (parking, driveways)
− - Light trucks
− - Heavy trucks / loading areas
−default: Passenger vehicles (parking, driveways)
+ - "Pervious concrete"
+ - "Porous asphalt"
+ - "Permeable interlocking concrete pavers"
+ - "Concrete grid pavers"
```
−## Hydrologic Design Mode {toc}
+### Pervious concrete carries the heaviest sustained loads of the four, needs no edge restraint, and is placed by a specialty crew whose availability sets the schedule; its surface ravels under snowplow blades and turning trucks where the crew compacted it short, and it is the surface most often lost to surface clogging because its voids are smallest. Porous asphalt is placed by an ordinary paving crew from a plant that has produced an open-graded mixture, costs the least per square foot, and depends on a modified binder and fibers to hold the voids open through a hot summer; it is the surface that closes first where a sealcoat or a conventional overlay is mistakenly applied in service. Permeable pavers infiltrate through joints that a vacuum sweeper can clean and a crew can refill, carry truck loads on an 80 mm unit with a herringbone pattern, can be lifted and relaid over a utility repair, and cost the most per square foot in material and labor; their joints are the opening a pedestrian notices and the dimension an accessible route is checked against. Concrete grid pavers leave most of their area open to aggregate or turf, carry the intermittent loads of a fire lane or overflow parking, and rut under daily traffic. {note}
−## The hydrologic mode is the single most consequential design decision, and it is governed by the measured infiltration capacity of the native subgrade, not by assumption. {note}
+### Where more than one surface type is used on the project, the limits of each shall be as shown on [[drawing: the paving plan]].
−## Subgrade infiltration shall be measured by a double-ring infiltrometer test in accordance with ASTM D3385 at the proposed subgrade elevation before the hydrologic mode is finalized.
+## Hydrologic Mode {toc}
−## Subgrade soil shall additionally be characterized by particle-size distribution per ASTM D7928 where the double-ring result is marginal or the soil is fine-grained.
+### The hydrologic mode of the section shall be as indicated in the datasheet.
−## Full infiltration mode shall be used only where the native soil saturated hydraulic conductivity is at least 0.27 in/hr; soils below this threshold, or sites within 2 ft of the seasonal high groundwater table, shall use partial or no-infiltration mode.
+```datasheet
+label: Hydrologic Mode
+type: radio
+options:
+ - "Full infiltration, all stored water infiltrates the subgrade"
+ - "Partial infiltration, an underdrain with a raised outlet releases what the subgrade has not infiltrated"
+ - "No infiltration, a liner isolates the reservoir and the underdrain releases all stored water"
+```
−## Assuming full infiltration on a clay subgrade without testing is the most common design error in permeable pavement. {note}
+### Full infiltration removes the stored volume from the surface system altogether, which earns the highest credit under a retention or recharge criterion, and it is available only where the subgrade drains fast enough to empty the reservoir within the drawdown time, the groundwater is far enough below, and the pavement is outside every setback that protects a foundation or a well. Partial infiltration holds a chosen depth of water against the subgrade through a raised outlet and releases the rest through the underdrain, which is the mode for a slow subgrade that still infiltrates something, and the one most design manuals assign where the measured rate falls between the floor for infiltration credit and the rate that empties the reservoir unaided. No infiltration lines the reservoir and routes every drop through the underdrain, which converts the pavement into detention with a water-quality benefit, and is the mode over a contaminated site, an expansive or collapsible soil, a fill, within a well setback, or where the design manual classifies the surface as a hotspot. {note}
−## The hydrologic mode shall be based on the measured ASTM D3385 result; assuming full infiltration without testing shall not be done.
+### Requirements in this standard that apply to an infiltration subgrade apply where full or partial infiltration is selected, and requirements that apply to a lined section apply where no infiltration is selected.
−## No-infiltration mode with an impermeable liner and full underdrain drawdown shall be used over contaminated subgrades, over expansive or collapsible soils, or where infiltration is prohibited by the geotechnical engineer or local authority.
+## Subgrade Infiltration Rate {toc}
+### The infiltration rate of the subgrade at the reservoir bottom shall be measured in the field by the method indicated in the datasheet, at not fewer than one test per pavement cell and not fewer than one test for each 7,000 ft² of pavement, at the elevation of the reservoir bottom.
+
```datasheet
−label: Hydrologic design mode
−type: radio
+label: Subgrade Infiltration Test Method
+type: select
options:
− - Full infiltration (no underdrain)
− - Partial infiltration (underdrain with raised outlet)
− - No infiltration (impermeable liner, full underdrain)
−default: Partial infiltration (underdrain with raised outlet)
+ - "Double-ring infiltrometer per ASTM D3385"
+ - "Test pit falling-head or constant-head test per the governing stormwater design manual"
+ - "Borehole percolation test per the governing stormwater design manual"
+ - "Laboratory hydraulic conductivity of undisturbed samples per ASTM D5084"
```
+### A double-ring infiltrometer measures the rate on a prepared horizontal face at the reservoir bottom and is the method most design manuals name for a pavement; a test pit wets the full excavation depth and suits a layered soil; a borehole test reaches depth quickly and overstates the rate where the hole crosses a permeable seam; and a laboratory test on an undisturbed sample gives a controlled value for a cohesive soil but misses the fissures and root channels that carry most of the flow in the field. Many design manuals accept only one or two of these for infiltration credit, and that acceptance decides the method more often than the soil does. {note}
+
+### The design infiltration rate of the subgrade shall be as indicated in the datasheet.
+
```datasheet
−label: Measured subgrade infiltration rate (ASTM D3385)
+label: Design Subgrade Infiltration Rate
type: range
unit: in/hr
min: 0
−max: 2
+max: 20
step: 0.01
−drawing_ref: true
+drawing_ref: "the infiltration test results in the geotechnical investigation report"
default: deferred
+constraint: exact
```
+### The design infiltration rate shall be the measured rate divided by the factor of safety the governing stormwater design manual applies to the test method used, and where the manual states no factor, by 2.
+
+### Where the design infiltration rate falls below the minimum rate the governing stormwater design manual accepts for infiltration credit, full infiltration shall not be constructed, and the Contractor shall report the result to the Engineer of Record before the hydrologic mode is confirmed.
+
+### A rate taken from a soil survey texture class rather than measured at the reservoir bottom is the most common cause of a permeable pavement that holds water for days and of a permit certification the Authority Having Jurisdiction refuses; a clay subgrade tested at the surface, where roots and desiccation cracks carry water, reads several times faster than the same clay two feet down where the reservoir sits. {note}
+
+## Groundwater, Bedrock, and Setbacks {toc}
+
+### The reservoir bottom shall be separated from [[parameter: seasonal-high-groundwater-elevation]] by not less than the vertical distance indicated in the datasheet.
+
```datasheet
−label: Separation to seasonal high groundwater
+label: Vertical Separation from Seasonal High Groundwater to the Reservoir Bottom
type: range
unit: ft
min: 0
−max: 20
−step: 0.5
−default: 2
+max: 10
+setpoints: [0, 1, 2, 3, 4, 5, 6, 8, 10]
+derived: "the hydrologic mode and the separation the governing stormwater design manual requires for that mode"
+default: derived
+constraint: min
```
−## Setbacks and Contributing Area {toc}
+### Separation is what the design manual trades for infiltration credit: an infiltrating reservoir needs unsaturated soil beneath it to drain into and to treat through, and a lined section needs none beyond what keeps the liner from floating. Groundwater that rises into the stone takes the storage it occupies, and the elevation that governs is the seasonal high, not the level on the day of the boring. {note}
−## Permeable pavement is sized for direct precipitation plus a limited run-on area; a maximum contributing impervious-to-permeable surface ratio of 2:1 is a common BMP rule, and routing a large impervious catchment onto a small permeable surface overwhelms the reservoir and causes failure. {note}
+### The reservoir bottom of an infiltrating section shall be separated from bedrock by not less than the distance the governing stormwater design manual requires, and the geotechnical investigation report shall confirm the bedrock elevation at each cell.
−## The contributing impervious drainage area routed onto the permeable surface shall not exceed the ratio established by the governing stormwater authority, and in no case shall it exceed 2:1 (impervious to permeable) without specific design justification.
+### An infiltrating section shall be set back from every building foundation by not less than the horizontal distance indicated in the datasheet, or shall be lined where it lies closer.
−## Full-infiltration systems shall be set back a minimum of 10 ft horizontally from building foundations.
+```datasheet
+label: Horizontal Setback of an Infiltrating Section from a Building Foundation
+type: range
+unit: ft
+min: 0
+max: 25
+setpoints: [0, 5, 10, 15, 20, 25]
+derived: "the setback the governing stormwater design manual requires for an infiltrating practice beside a foundation"
+default: derived
+constraint: min
+```
−## Permeable pavement shall be set back from potable water wells by the distance required by the local authority, and in no case less than 50 ft.
+### The section shall be kept outside the sanitary setback and the wellhead protection area of every water supply well shown on [[drawing: the well plan and the site utility plan]], and where a permeable pavement is shown within that setback it shall be a lined, no-infiltration section.
−## Sediment pre-treatment — a vegetated filter strip, gravel diaphragm, or inlet sump — shall be provided at upgradient edges that receive run-on, to reduce sediment loading and extend service life.
+### Infiltration beside a foundation saturates the bearing soil and the backfill against the wall, and infiltration up-gradient of a well delivers the de-icing salt, the oil, and the dissolved load of the pavement to the aquifer the well draws from; the well construction code and the design manual set the distances, and the well plan is where the Engineer of Record reconciles them. {note}
−## Permeable pavement located beneath concentrated tree canopy receives leaf litter and organic debris that accelerate surface clogging. {note}
+## Design Traffic Class {toc}
−## A vegetated buffer or pre-treatment filter strip should be provided to intercept leaf litter and debris where concentrated tree canopy overhangs the pavement.
+### The design traffic class of the pavement shall be as indicated in the datasheet.
```datasheet
−label: 'Contributing impervious area ratio (impervious : permeable)'
+label: Design Traffic Class
type: select
options:
− - 0:1 (direct rainfall only)
− - 1:1
− - 2:1 (maximum without justification)
−default: 1:1
+ - "Pedestrian and bicycle"
+ - "Passenger vehicles in parking stalls and drive aisles"
+ - "Light trucks, delivery vehicles, and emergency apparatus"
+ - "Heavy trucks and loading areas"
```
+### The traffic class sets the surface thickness, the paver thickness and laying pattern, the structural depth of the base, and the aggregate angularity, and each surface type carries a ceiling: grid pavers stop at intermittent emergency and overflow use, pavers and porous asphalt carry delivery trucks on an 80 mm unit or a thickened course, and pervious concrete and 100 mm pavers on a deep base reach the loading class, where the structural layer is designed as a pavement and the reservoir is sized to the thicker of the structural and the hydrologic demand. {note}
+
+### The structural depth of the section for the design traffic class shall be as stated in the pavement design in the geotechnical investigation report, and where that depth exceeds the reservoir depth the stormwater management report requires, the greater depth shall be built.
+
+## Run-On and Pretreatment {toc}
+
+### The ratio of the impervious area draining onto the permeable surface to the area of the permeable surface shall not exceed the value indicated in the datasheet.
+
```datasheet
−label: Setback from building foundations (full-infiltration mode)
+label: Run-On Area Ratio, Impervious Area to Permeable Pavement Area
type: range
−unit: ft
−min: 10
−max: 50
−step: 1
−default: 10
+unit: 'to 1'
+min: 0
+max: 5
+setpoints: [0, 0.5, 1, 2, 3, 5]
+constraint: max
```
−## Freeze-Thaw Exposure {toc}
+### A pavement that receives only the rain that falls on it clogs at the rate its own traffic delivers sediment; every square foot of roof, drive, or landscape routed onto it adds that area's load to the same voids and shortens the sweeping interval in proportion. Most design manuals cap the ratio between 2 and 3 to 1, a roof with no sediment is counted more generously than a landscape bed, and a ratio above the cap is a design decision the manual asks the engineer to justify. {note}
−## Open-graded reservoir aggregate drains freely and is generally frost-tolerant, but the surface course itself must resist freeze-thaw and de-icing-salt damage in cold climates. {note}
+### Run-on from a contributing area shall pass through the pretreatment indicated in the datasheet before it reaches the permeable surface.
−## In freeze-thaw climates, PICP units shall be qualified to ASTM C1645 with a maximum 1% mass loss after 50 freeze-thaw cycles in de-icing solution.
+```datasheet
+label: Run-On Pretreatment
+type: select
+options:
+ - "Vegetated filter strip along the receiving edge"
+ - "Gravel diaphragm or stone trench along the receiving edge"
+ - "Sumped inlet or forebay at the point of concentrated entry"
+ - "None, the pavement receives direct rainfall only"
+```
−## Winter sand applied for traction fills joints and surface voids and is a leading cause of premature clogging. {note}
+### A filter strip settles sheet flow across a grass width before it reaches the pavement and needs mowing and an edge that stays level with the pavement; a gravel diaphragm spreads concentrated flow into sheet flow and traps the coarse load where a shovel can reach it; a sumped inlet or forebay is the device for a pipe or a swale that enters at one point and is cleaned by a vacuum truck; and no pretreatment is the case for a pavement with no run-on, which is the condition the stormwater credit is simplest to defend for. {note}
−## In freeze-thaw climates, an anti-icing or pre-wetting strategy should be specified in preference to sanding.
+### Landscape beds, lawns, and bare soil adjoining the permeable surface shall be graded so that they do not drain onto it, or shall be separated from it by a curb or a pretreatment edge.
−## Any sand applied for traction shall be removed by vacuum sweeping promptly after the event.
+## Freeze-Thaw and Winter Service {toc}
+### Where [[parameter: frost-depth]] is greater than zero, permeable interlocking concrete pavers shall be qualified by test in accordance with ASTM C1645/C1645M with a mass loss not exceeding 1 percent after 50 cycles in the saline solution.
+
+### Where [[parameter: frost-depth]] is greater than zero, pervious concrete shall contain an air-entraining admixture at the dosage stated in the mixture design.
+
+### An open-graded reservoir drains freely and does not heave, which is why a permeable pavement in a cold climate is built on the same reservoir as one in a warm climate; the surface course is what the freeze-thaw cycle attacks, through the de-icing salt that collects in the voids and the joints, and the paver test and the entrained air are what resist it. {note}
+
+### The operation and maintenance manual shall state that sand and other abrasives shall not be applied to the permeable surface for winter traction, and that any abrasive applied shall be removed by vacuum sweeping before the next thaw.
+
+### Winter sand is the single largest source of the fines that close a permeable surface, and a season of sanding undoes a year of sweeping; a permeable surface drains the meltwater that would otherwise refreeze, so it needs less de-icing than the conventional pavement beside it. {note}
+
+# Pervious Concrete {toc}
+
+## Requirements in this article apply where pervious concrete is selected as the surface type.
+
+## Pervious Concrete Mixture {toc}
+
+### Pervious concrete shall be designed under ACI 522.1 to the design void content indicated in the datasheet, verified on the trial batch in accordance with ASTM C1688/C1688M.
+
```datasheet
−label: Freeze-thaw exposure
−type: radio
−options:
− - Freeze-thaw climate (ASTM C1645 required for PICP)
− - Non-freezing climate
−default: Freeze-thaw climate (ASTM C1645 required for PICP)
+label: Pervious Concrete Design Void Content
+type: range
+unit: '%'
+min: 15
+max: 30
+step: 1
+default: 20
+constraint: exact
```
−# Surface Course {toc}
+### Void content is the property that sets both the infiltration rate and the strength, in opposite directions: at 15 percent the voids barely connect and the surface clogs within a season, and above 25 percent the paste bridges between the aggregate particles thin to the point that the surface ravels under a turning tire. Twenty percent is the value most mixture designs land on and most acceptance ranges center on; a lower target is set for a loading area where strength governs, and a higher target where the design manual credits the surface rate and the traffic is light. {note}
−## Pervious Concrete {toc}
+### The cementitious materials shall be portland cement conforming to ASTM C150/C150M or blended cement conforming to ASTM C595/C595M, with or without supplementary cementitious materials, at the content the mixture design states.
−## Pervious concrete derives its permeability from a high interconnected void content created by a near-zero-slump, gap-graded mix with little or no fine aggregate; void content and infiltration rate, not compressive strength, are the controlling acceptance properties. {note}
+### The coarse aggregate shall conform to ASTM C33/C33M and shall be a single-size or narrowly graded aggregate of 3/8 in. or 1/2 in. nominal maximum size, and fine aggregate, where any is used, shall not exceed the proportion the mixture design states.
−## Pervious concrete void content shall be 15% to 25%, with a target of 18% to 22% for most applications, verified per ASTM C1754.
+### Admixtures shall conform to ASTM C260/C260M or ASTM C494/C494M, and a hydration-stabilizing admixture shall be used where the time from batching to discharge exceeds 60 minutes.
−## Pervious concrete compressive strength shall be a minimum of 2,500 psi for vehicular applications.
+### The water-cementitious materials ratio shall be as stated in the mixture design, and water shall not be added at the site beyond the quantity the mixture design permits for the measured moisture of the aggregate.
−## Pervious concrete shall achieve an as-placed surface infiltration rate of at least 100 in/hr when tested per ASTM C1701.
+### Pervious concrete has no slump to measure and is judged at the chute by the sheen of the paste: a mixture too dry crumbles and bonds nowhere, a mixture too wet lets the paste run to the bottom and seal the voids, and the margin between the two is a few gallons per cubic yard, which is why the water is controlled at the plant and not at the truck. {note}
−## Pervious concrete shall be cured under plastic sheeting for a minimum of 7 days.
+### The fresh density of the delivered concrete, determined in accordance with ASTM C1688/C1688M, shall be within 5 lb/ft³ of the design fresh density, and a load outside that range shall be rejected.
−## Surface drying during curing ravels the paste and weakens the bond at the void walls. {note}
+### The compressive strength of pervious concrete is reported in the mixture design for information and is not an acceptance criterion of this standard; acceptance rests on the fresh density, the hardened void content, the thickness, and the surface infiltration rate, because a strength cylinder of a no-fines mixture does not represent the compaction the surface receives in place. {note}
−## The pervious concrete thickness shall be specified, sized to the traffic loading and structural design while meeting the specified void content and compressive strength.
+## Pervious Concrete Thickness and Joints {toc}
+### The thickness of the pervious concrete surface course shall be as indicated in the datasheet.
+
```datasheet
−label: Pervious concrete thickness
+label: Pervious Concrete Thickness
type: range
unit: in
min: 4
−max: 8
+max: 12
step: 0.5
−default: 6
+drawing_ref: "the pavement section details on the civil drawings"
+default: deferred
+constraint: min
```
+### Contraction joints shall be formed by the method indicated in the datasheet, at a spacing not exceeding 20 ft, to a depth not less than one quarter of the thickness.
+
```datasheet
−label: Pervious concrete target void content
+label: Pervious Concrete Contraction Joint Method
+type: radio
+options:
+ - "Rolled into the plastic concrete with a joint roller"
+ - "Sawed after curing"
+ - "No contraction joints"
+```
+
+### A rolled joint is formed minutes after compaction with the same crew and leaves a clean, open groove, and it must be struck before the surface stiffens; a sawed joint is cut after the cure, which spalls the void walls along the cut and leaves slurry in the voids unless the cut is vacuumed, and it is used where the placement is too large to joint by hand; omitting joints is the practice of many placements, because a no-fines mixture shrinks little and cracks that form in it stay tight and pass water, and it is accepted where a random crack is not an appearance defect. {note}
+
+### Isolation joints shall be provided where the pervious concrete abuts a structure, a conventional pavement, or a curb, and the joint filler shall not be a material that migrates into the voids.
+
+## Pervious Concrete Placement and Curing {toc}
+
+### The choker or reservoir surface shall be wetted before placement so that it does not draw water from the mixture, and no standing water shall remain on it.
+
+### Pervious concrete shall be discharged within 60 minutes of batching, or within 90 minutes where a hydration-stabilizing admixture is used, and a load not discharged within that time shall be rejected.
+
+### Pervious concrete shall be placed with a mechanical screed and compacted with a roller or a vibratory screed to the thickness and density the mock-up established, and shall not be finished with a float or trowel.
+
+### A troweled or over-worked surface closes the voids at the exact face through which the water enters, and the pavement beneath it is then a dense slab over a reservoir it cannot reach. {note}
+
+### Each placement shall be covered with polyethylene sheeting within 20 minutes of compaction and shall remain covered for the curing period indicated in the datasheet, with the sheeting held down continuously along every edge.
+
+```datasheet
+label: Pervious Concrete Covered Curing Period
type: range
+unit: days
+min: 7
+max: 14
+setpoints: [7, 10, 14]
+default: 7
+constraint: min
+```
+
+### A no-fines mixture has a paste film a fraction of a millimeter thick on every particle and no body of concrete to hold moisture, so it dries from every void at once; seven days under sheeting is the curing period ACI 522.1 requires and the one that stops the surface from raveling, and a longer period is set for a hot, windy, or low-humidity site where the sheeting alone is marginal. {note}
+
+### No vehicle shall drive on pervious concrete until the curing period has ended, and no truck until 14 days after placement.
+
+# Porous Asphalt {toc}
+
+## Requirements in this article apply where porous asphalt is selected as the surface type.
+
+## Porous Asphalt Mixture {toc}
+
+### Porous asphalt shall be designed as an open-graded mixture in accordance with ASTM D7064/D7064M and NAPA IS 131 to the design air void content indicated in the datasheet.
+
+```datasheet
+label: Porous Asphalt Design Air Void Content
+type: range
unit: '%'
−min: 15
−max: 25
+min: 16
+max: 24
step: 1
−default: 20
+default: 18
+constraint: exact
```
+### Eighteen percent air voids is the level at which the voids of an open-graded mixture connect reliably and the mixture still holds its stone skeleton under a steel-wheel roller; a lower target is accepted where a thin choker and a heavy binder make the surface tighter than the hydrology needs, and a higher target is set where the design manual credits the surface rate directly, at the cost of a mixture that drains binder in the haul truck unless the fibers and modifier hold it. {note}
+
+### The nominal maximum aggregate size of the mixture shall be as indicated in the datasheet.
+
```datasheet
−label: Pervious concrete minimum compressive strength
+label: Porous Asphalt Nominal Maximum Aggregate Size
type: range
−unit: psi
−min: 2500
−max: 4000
−step: 100
−default: 2500
+unit: mm
+min: 9.5
+max: 19
+setpoints: [9.5, 12.5, 19]
+constraint: exact
```
−## Porous Asphalt {toc}
+### The coarse aggregate shall be crushed stone with not less than 90 percent of particles having two or more fractured faces per ASTM D5821, a Los Angeles abrasion loss not exceeding 40 percent per ASTM C131/C131M, and a sodium sulfate soundness loss not exceeding 12 percent per ASTM C88/C88M.
−## Porous asphalt is an open-graded asphalt wearing course whose interconnected voids carry water vertically into the reservoir; its mix is gap-graded with a polymer-modified or fiber-stabilized binder to resist binder drain-down during placement. {note}
+### The binder performance grade shall be as indicated in the datasheet.
−## Porous asphalt surface void content shall be 15% to 20%.
+```datasheet
+label: Porous Asphalt Binder Performance Grade
+type: select
+drawing_ref: "the pavement design in the geotechnical investigation report"
+options:
+ - "PG 58-28"
+ - "PG 64-22"
+ - "PG 64-28"
+ - "PG 70-22"
+ - "PG 70-28"
+ - "PG 76-22"
+ - "PG 76-28"
+ - "PG 82-22"
+default: deferred
+```
−## The porous asphalt wearing course shall be 3 in. to 4 in. compacted thickness.
+### The binder shall be modified or stabilized as indicated in the datasheet.
−## Porous asphalt shall be compacted with a static steel-wheel roller; vibratory compaction crushes the aggregate skeleton and closes the surface voids and shall not be used.
+```datasheet
+label: Porous Asphalt Binder Modification
+type: select
+options:
+ - "Polymer-modified binder"
+ - "Cellulose or mineral fiber stabilizer in the mixture"
+ - "Polymer-modified binder and fiber stabilizer together"
+```
+### An open-graded mixture carries a thick binder film on a few points of contact and has no fine aggregate to hold the binder in place, so a neat binder drains to the bottom of the haul truck and the bottom of the mat; a polymer-modified binder is stiff enough at haul temperature to stay on the stone and is the modification every porous asphalt placed under truck traffic carries; fibers hold the binder by absorption and are the lower-cost answer on a parking lot in a mild climate; and the two together are specified where the grade is two steps above the climate grade and the haul is long. {note}
+
+### The binder content of the mixture shall be not less than the value indicated in the datasheet.
+
```datasheet
−label: Porous asphalt compacted thickness
+label: Porous Asphalt Binder Content
type: range
−unit: in
−min: 3
−max: 4
+unit: '% of mixture'
+min: 5
+max: 7.5
step: 0.25
−default: 3.5
+default: 6
+constraint: min
```
+### The draindown of the mixture, determined in accordance with ASTM D6390 at the production temperature, shall not exceed 0.3 percent.
+
+### A porous asphalt mixture is richer in binder than a dense mixture of the same stone, because durability in an open-graded mixture comes from the thickness of the film and not from the density of the mat; a mixture designed lean to save binder ravels at the surface in its first winter and is the porous asphalt that gave the material its early reputation. {note}
+
+## Porous Asphalt Thickness and Placement {toc}
+
+### The compacted thickness of the porous asphalt surface course shall be as indicated in the datasheet.
+
```datasheet
−label: Porous asphalt target void content
+label: Porous Asphalt Compacted Thickness
type: range
−unit: '%'
−min: 15
−max: 20
−step: 1
−default: 18
+unit: in
+min: 2
+max: 6
+step: 0.5
+drawing_ref: "the pavement section details on the civil drawings"
+default: deferred
+constraint: min
```
−## Permeable Interlocking Concrete Pavers {toc}
+### Porous asphalt shall be placed on a choker course of the gradation indicated in the Bedding and Choker Courses section of this standard, and no prime coat or tack coat shall be applied to the choker.
−## PICP infiltrates between the units rather than through them; water passes through open, aggregate-filled joints into a thin washed-stone bedding course and on into the reservoir, so joint width, joint-fill gradation, and bedding material control the infiltration rate. {note}
+### Porous asphalt shall be delivered and placed within the temperature range the job-mix formula states, and shall not be placed when the air temperature is below 50°F or on a wet or frozen choker.
−## PICP units shall be solid concrete interlocking paving units conforming to ASTM C936 with a minimum compressive strength of 8,000 psi.
+### Porous asphalt shall be compacted with static steel-wheel rollers in not more than the number of passes the mock-up established, and vibratory compaction shall not be used.
−## PICP units shall be 80 mm thick for vehicular applications.
+### Vibration and excess rolling crush the stone-on-stone contacts and close the voids the mixture was designed to hold; the mat reaches its density in two to four static passes while it is still above the binder's compaction temperature, and a roller that keeps working after that is sealing the surface. {note}
−## PICP units 60 mm thick may be used in pedestrian-only areas not subject to vehicular loading.
+### No vehicle shall drive on porous asphalt until the mat has cooled to ambient temperature, and no truck until 24 hours after placement.
−## Joint openings shall be 3/16 in. to 1/2 in. wide and filled with clean, washed ASTM No. 8 or No. 9 aggregate.
+### A sealcoat, a slurry seal, a fog seal, or a dense overlay shall not be applied to porous asphalt, and the operation and maintenance manual shall state that prohibition.
−## Sand shall not be used as bedding or joint fill in any permeable pavement layer.
+# Permeable Interlocking Concrete Pavers {toc}
−## Sand migrates into the reservoir voids and causes rapid, irreversible clogging and loss of infiltration capacity. {note}
+## Requirements in this article apply where permeable interlocking concrete pavers are selected as the surface type.
−## The PICP bedding course shall be 2 in. of washed ASTM No. 8 stone placed over the reservoir base; no sand setting bed is permitted.
+## Paver Units {toc}
−```datasheet
−label: PICP paver thickness
−type: radio
−options:
− - 80 mm (vehicular)
− - 60 mm (pedestrian only)
−default: 80 mm (vehicular)
−```
+### Paving units shall conform to ASTM C936/C936M, with a compressive strength not less than 8,000 psi and an absorption not exceeding 5 percent, and shall be formed with spacer bars or a profile that holds the joint opening this standard requires.
+### The paver thickness shall be as indicated in the datasheet.
+
```datasheet
−label: PICP minimum paver compressive strength
+label: Paver Thickness
type: range
−unit: psi
−min: 8000
−max: 11000
−step: 500
−default: 8000
+unit: mm
+min: 60
+max: 120
+setpoints: [60, 80, 100, 120]
+derived: "the design traffic class under ASCE 68, 80 mm where any vehicle uses the pavement"
+default: derived
+constraint: min
```
+### Pavers in a pavement that carries vehicles shall be not less than 80 mm thick, and 60 mm pavers shall be used only where the design traffic class is pedestrian and bicycle.
+
+### The joint opening between adjacent pavers shall be as indicated in the datasheet.
+
```datasheet
−label: PICP joint width
+label: Paver Joint Opening
type: range
unit: in
min: 0.1875
max: 0.5
−step: 0.0625
−default: 0.25
+setpoints: [0.1875, 0.25, 0.3125, 0.375, 0.5]
+constraint: exact
```
+### The joint is the whole infiltration path of a paver pavement, and its width is a product dimension set by the spacer bars: a narrow joint holds a small stone, infiltrates less, and is the opening an accessible route tolerates; a wide joint infiltrates more, takes a larger stone that resists being vacuumed out, and reaches the 1/2 in. that the accessibility standard sets as the limit for an opening in an accessible route. {note}
+
+### The color, texture, and shape of the paving units shall be as shown on [[drawing: the paving plan and the finish schedule]].
+
+## Joint Fill and Laying Pattern {toc}
+
+### Joints shall be filled with washed stone of the gradation indicated in the datasheet, swept and vibrated into the joints until they are full, and topped up after the final compaction so that the fill is flush with the chamfer.
+
```datasheet
−label: PICP joint-fill aggregate
−type: radio
+label: Paver Joint Fill Gradation per ASTM D448
+type: select
options:
− - ASTM No. 8 washed stone
− - ASTM No. 9 washed stone
−default: ASTM No. 8 washed stone
+ - "No. 8"
+ - "No. 89"
+ - "No. 9"
```
−## Concrete Grid Pavers {toc}
+### No. 8 stone is the fill for a joint of 3/8 in. and wider and the gradation most paver manufacturers and the ASCE 68 design method assume; No. 89 enters a 1/4 in. joint and holds its position under a vacuum sweeper better than the finer stone; and No. 9 is the fill for a joint narrower than 1/4 in., where it is the only stone that enters, and it is the fill a sweeper set too aggressively removes. The fill gradation and the joint opening are selected together, and a fill that will not enter the joint leaves the surface unfilled and the pavers free to creep. {note}
−## Concrete grid pavers are open-cell concrete frames whose cells are filled with washed aggregate or topsoil and turf; they spread intermittent vehicle loads while leaving most of the plan area open to infiltration, and are intended for fire lanes, emergency access, and overflow parking rather than continuous traffic. {note}
+### Sand, stone dust, and polymeric joint sand shall not be used as joint fill or as bedding in any layer of a permeable pavement.
−## Concrete grid paver cells shall be filled with clean washed aggregate or with a topsoil/turf medium as shown for the application.
+### Pavers in a pavement that carries vehicles shall be laid in a herringbone pattern at 45 or 90 degrees to the direction of travel, and the pattern in a pedestrian pavement shall be as shown on [[drawing: the paving plan]].
−## Grid pavers shall be set on a washed-stone bedding course over the reservoir base, with no sand setting bed.
+### A herringbone pattern locks every unit against its neighbors in both directions, so a braking or turning wheel cannot shove a row; a running bond or a stack bond carries the same load but creeps in the direction of its continuous joints under traffic, which is why ASCE 68 limits those patterns to pedestrian use. {note}
+### Cut units along an edge in a pavement that carries vehicles shall be not smaller than one third of a full unit, and smaller spaces shall be filled by adjusting the pattern or with a concrete infill of the same thickness.
+
+### After the joints are filled, the pavement shall be compacted with a plate compactor of not less than 5,000 lbf centrifugal force, fitted with a protective pad, in not fewer than two passes, until the units are seated in the bedding and the joints are full.
+
+### The finished paver surface shall not deviate from a 10 ft straightedge by more than 3/8 in., and the lippage between adjacent units shall not exceed 1/8 in.
+
+# Concrete Grid Pavers {toc}
+
+## Requirements in this article apply where concrete grid pavers are selected as the surface type.
+
+## Grid paving units shall conform to ASTM C1319, with a compressive strength not less than 5,000 psi, and shall be not less than 3-1/8 in. thick.
+
+## The cells of the grid units shall be filled as indicated in the datasheet.
+
```datasheet
−label: Concrete grid paver cell fill
+label: Grid Paver Cell Fill
type: radio
options:
− - Washed aggregate fill
− - Topsoil and turf fill
−default: Washed aggregate fill
+ - "Washed stone of the joint fill gradation"
+ - "Topsoil and turf over a stone bedding"
```
−# Reservoir Base and Bedding {toc}
+## Where the cells are filled with topsoil and turf, the topsoil shall be a sandy growing medium placed to 1/2 in. below the top of the unit, and the turf shall be established and mowed twice before the pavement is placed in service.
−## The reservoir base performs two jobs at once — it supports the traffic load structurally and it stores stormwater in its open voids — and its depth is set by the thicker of the two demands. {note}
+## Grid pavers shall be set on the bedding course this standard requires for pavers, shall be laid tight against one another, and shall be restrained at every edge.
−## The reservoir base shall be clean, washed, open-graded crushed stone with a minimum void ratio of 40%.
+## Grid pavers shall not be used where the design traffic class is heavy trucks and loading areas, and a grid pavement used as a fire lane shall be marked as the fire code official requires under [[sync/pavement-markings]].
−## Reservoir aggregate shall be the AASHTO gradation appropriate to the surface type: AASHTO No. 57 for pervious concrete, AASHTO No. 2 or No. 3 for porous asphalt, and AASHTO No. 2, No. 3, or No. 4 for PICP.
+# Bedding and Choker Courses {toc}
−## The reservoir base depth shall be sized to store the design storm runoff volume required by the governing stormwater authority (commonly the 1-year or 2-year, 24-hour storm) and to satisfy the structural thickness for the traffic class, whichever is greater.
+## The bedding course beneath pavers and grid pavers shall be 2 in. of washed No. 8 stone per ASTM D448, screeded to grade over the base course and not compacted before the units are set.
−## Reservoir aggregate shall not be choked with fines or stone dust.
+## A No. 8 bedding is the one layer every paver manufacturer, ASCE 68, and the paver industry design method agree on, because it is the largest stone that screeds true under a 2 in. depth and the smallest that passes water as fast as the joints deliver it; a sand bedding is the single most common defect in a permeable paver pavement, and it turns the section into a conventional one that drains nowhere. {note}
−## Only clean washed stone maintains the void ratio and the structural angularity that carry load and store water. {note}
+## The choker or base course between the surface course and the reservoir shall be of the gradation indicated in the datasheet.
−## Open-graded reservoir aggregate shall be compacted with a vibratory plate compactor in lifts.
+```datasheet
+label: Choker or Base Course Gradation per ASTM D448
+type: select
+options:
+ - "None, the surface course or bedding placed directly on the reservoir stone"
+ - "No. 57"
+ - "No. 67"
+```
−## Conventional Proctor-based density specifications shall not be used as the acceptance basis for single-size open-graded stone.
+## A choker course of No. 57 stone keys into the top of a large reservoir stone to make a surface that a paver screed, a pervious concrete screed, or an asphalt paver can run on without the surface material falling into the voids below, and in a paver section it is the 4 in. base course ASCE 68 names between the bedding and the subbase; No. 67 chokes a No. 3 or No. 4 reservoir more tightly where the surface is porous asphalt placed in a thin lift; and no choker is the section where the reservoir itself is No. 57 stone and the pervious concrete or the bedding is placed on it directly. {note}
−## Conventional Proctor-based density specifications do not apply to single-size open-graded stone, because the test method assumes a continuous particle-size distribution that is absent in open-graded aggregate. {note}
+## The thickness of the choker or base course shall be as indicated in the datasheet.
−## The number of compaction passes per lift shall be established on the demonstration mock-up and held for production.
+```datasheet
+label: Choker or Base Course Thickness
+type: range
+unit: in
+min: 0
+max: 8
+step: 1
+drawing_ref: "the pavement section details on the civil drawings"
+default: deferred
+constraint: min
+```
+## Choker and base stone shall meet the washed-stone, fines, and fractured-face requirements of the Reservoir Aggregate section of this standard, shall be placed in one lift, and shall be compacted with a vibratory plate or roller until the surface is firm and the stone does not move under foot.
+
+# Reservoir Aggregate {toc}
+
+## The reservoir performs two jobs at once, it carries the traffic load to the subgrade and it stores the stormwater the permit credits, and its depth is set by the thicker of the two demands. The storage is in the voids between the stones, so every property of the reservoir stone serves the voids: it is single-sized so the small particles do not fill the gaps between the large ones, it is washed so there are no fines to carry down into the subgrade, and it is crushed so the angular faces lock and the stone does not consolidate under load. {note}
+
+## Reservoir Gradation and Quality {toc}
+
+### Reservoir stone shall be washed, crushed, angular stone of the gradation indicated in the datasheet.
+
```datasheet
−label: Reservoir aggregate gradation
−type: radio
+label: Reservoir Aggregate Gradation per ASTM D448
+type: select
options:
− - AASHTO No. 57 (pervious concrete)
− - AASHTO No. 2 (porous asphalt / PICP)
− - AASHTO No. 3 (porous asphalt / PICP)
− - AASHTO No. 4 (PICP)
−default: AASHTO No. 3 (porous asphalt / PICP)
+ - "No. 2"
+ - "No. 3"
+ - "No. 4"
+ - "No. 57"
+ - "No. 67"
```
+### The larger gradations store the most water per cubic foot, let it move through the reservoir to the underdrain fastest, and are the subbase ASCE 68 names beneath a paver base course; they are also the hardest to place to a level bed and need a choker before any surface can be placed on them. No. 57 stone is the reservoir most pervious concrete is placed on directly and the base course of a paver section, with a void ratio a few points lower and a surface a screed can run on; No. 67 is used where a thin reservoir under a pedestrian pavement does not justify a two-stone section. A reservoir deeper than about 12 in. is usually built of the large stone with a choker, and a shallow one of No. 57 alone. {note}
+
+### Reservoir stone shall have not more than 2 percent by mass passing the No. 200 sieve per ASTM C117, not less than 90 percent of particles with two or more fractured faces per ASTM D5821, a Los Angeles abrasion loss not exceeding 40 percent per ASTM C131/C131M, and a sodium sulfate soundness loss not exceeding 12 percent per ASTM C88/C88M.
+
+### Recycled concrete aggregate, slag, rounded gravel, limestone screenings, and any aggregate with a fines content above the limit shall not be used in any layer of the section unless the Engineer of Record permits it in writing for the project.
+
+### Recycled concrete releases lime into the water that passes through it, which raises the pH of the discharge and cements the fines at the reservoir bottom, and rounded gravel neither locks to carry the load nor holds the void ratio the credit assumes. {note}
+
+## Reservoir Depth and Void Ratio {toc}
+
+### The depth of the reservoir shall be as indicated in the datasheet.
+
```datasheet
−label: Reservoir base depth
+label: Reservoir Depth
type: range
unit: in
min: 6
−max: 36
+max: 48
step: 1
−default: 15
+drawing_ref: "the stormwater management report and the pavement section details on the civil drawings"
+default: deferred
+constraint: min
```
+### The storage volume credited to the reservoir shall be computed with the void ratio indicated in the datasheet, and the Contractor shall furnish reservoir stone whose measured void ratio is not less than that value.
+
```datasheet
−label: Reservoir aggregate minimum void ratio
+label: Design Void Ratio of the Reservoir Aggregate
type: range
unit: '%'
−min: 40
−max: 50
−step: 1
+min: 25
+max: 45
+step: 5
default: 40
+constraint: min
```
−# Geotextile Separation {toc}
+### Forty percent is the void ratio the industry attributes to clean, crushed, single-sized stone and the value most design manuals cap the credit at; a rounded gravel or a graded stone falls short of it, and a reservoir credited at 40 percent and built with stone that yields 30 stores a quarter less than its permit assumes. {note}
−## A non-woven geotextile at the subgrade interface prevents fine subgrade soil from pumping up into the reservoir voids and clogging the storage; it is specified where the subgrade carries appreciable fines and omitted where the subgrade is clean and granular, since an unnecessary fabric can itself become a clogging plane. {note}
+### Where the reservoir bottom slopes, the reservoir shall be terraced with check dams or berms at the spacing and to the heights shown on [[drawing: the pavement section details and the reservoir grading plan]], so that the stored water is held across the cell rather than draining to its low end.
−## A non-woven geotextile separation layer shall be provided at the reservoir-base-to-subgrade interface where the subgrade soil contains appreciable fines, as determined from the ASTM D7928 gradation.
+### A reservoir built on a 2 percent subgrade slope holds its design depth at the downhill edge and nothing at the uphill edge, and the surface rate is then tested on a pavement whose storage is a fraction of the volume credited; the terraces are what make the plan-area storage real. {note}
−## Where a geotextile is provided, it shall be lapped a minimum of 12 in. at all seams and turned up at the perimeter against the edge restraint.
+## Reservoir Placement {toc}
−## Geotextile shall not be placed between the surface course and the reservoir base, where it would obstruct vertical infiltration.
+### Reservoir stone shall be placed from the edge of the cell inward, or from stone already placed, and no equipment shall operate on an infiltration subgrade.
+### Reservoir stone shall be placed in lifts not exceeding 8 in. in loose thickness and compacted with a vibratory plate or roller in not fewer than two passes per lift, until the stone does not move under the compactor and the surface is firm.
+
+### Density of the reservoir shall not be specified or accepted on a moisture-density relationship, and no proctor-based acceptance shall be applied to a single-sized stone.
+
+### A moisture-density test assumes a continuous gradation that packs tighter with water and effort, and a single-sized stone has neither; it seats under a few passes to a density the compactor cannot change, and the acceptance that means anything is the stone source, the washed-stone certification, and the compaction passes the mock-up established. {note}
+
+### Stone shall not be dumped in piles on the subgrade and spread by pushing, and the exposed subgrade shall be covered with geotextile or stone within the same working day it is excavated to grade.
+
+# Separation Geotextile {toc}
+
+## The geotextile at the reservoir boundary shall be as indicated in the datasheet.
+
```datasheet
−label: Geotextile separation at subgrade
+label: Separation Geotextile at the Reservoir Boundary
type: radio
options:
− - Non-woven geotextile provided (fines present)
− - Omitted (clean granular subgrade)
−default: Non-woven geotextile provided (fines present)
+ - "Nonwoven geotextile on the sides of the excavation and across the full reservoir bottom"
+ - "Nonwoven geotextile on the sides of the excavation only"
+ - "No geotextile at the reservoir boundary"
```
−# Underdrains and Outlet Control {toc}
+## A geotextile on the sides of the excavation keeps the adjoining soil from washing into the stone through the excavation face, and nearly every manufacturer and design manual calls for it. The bottom is the decision: a geotextile across the reservoir bottom separates the stone from a subgrade that would pump fines up into it, and it is also the plane on which the sediment that reaches the bottom of the reservoir collects, so a bottom fabric is the layer that blinds first on an infiltration subgrade and is the one most paver-industry guidance omits where the subgrade is sand or gravel. Omitting the geotextile altogether is the case for a clean granular subgrade in an excavation that will be stoned the day it is cut, and for a lined section where the cushion geotextile does the job. {note}
−## In partial- and no-infiltration modes, perforated underdrain pipe relieves the reservoir; its invert and outlet elevations set how much water is held for infiltration and how quickly the reservoir draws down, which in turn governs stormwater compliance. {note}
+## Where a geotextile is placed across the bottom of an infiltrating section, the geotextile shall be a nonwoven needle-punched geotextile furnished under [[sync/geosynthetics]] for the separation function, and a woven slit-film geotextile shall not be used.
−## Perforated underdrain pipe shall be provided in partial-infiltration and no-infiltration modes; full-infiltration systems do not require an underdrain.
+## Geotextile panels shall overlap not less than 12 in. at every seam, with the upslope panel lapped over the downslope panel, and shall be turned up the excavation face to the underside of the surface course.
−## In partial-infiltration mode, the underdrain outlet shall be raised to hold 6 in. to 12 in. of water above the subgrade, so that water infiltrates the subgrade before it overflows through the underdrain.
+## No geotextile shall be placed between the surface course and the reservoir, between the bedding and the base, or within the reservoir, where it would collect sediment and stop the vertical flow of water.
−## The reservoir shall draw down within 24 to 72 hours; 48 hours is the most common state stormwater BMP requirement and shall be the design basis unless the governing authority specifies otherwise.
+## A geotextile torn or punctured during stone placement shall be patched with a panel of the same material extending not less than 24 in. beyond the damage in every direction.
−## Holding water indefinitely defeats both the structural and the water-quality function — a saturated reservoir cannot store the next storm and a permanently submerged subgrade loses bearing — so the drawdown time is a firm design constraint, not a target. {note}
+# Impermeable Liner {toc}
−## The underdrain pipe size, invert elevation, raised-outlet elevation, and the connection to the site stormwater collection or detention system shall be coordinated with the project civil engineer and shown on the [[sync/stormwater-management-systems]] drawings.
+## The reservoir shall be lined as indicated in the datasheet.
−## Underdrain layout, outlet locations, and invert elevations shall be shown on the drawings. [[drawing: underdrain plan and profile]]
+```datasheet
+label: Impermeable Liner
+type: radio
+options:
+ - "Geomembrane liner across the reservoir bottom and up the sides of the excavation"
+ - "No liner"
+derived: "the hydrologic mode, a liner where no infiltration is selected and none otherwise"
+default: derived
+```
+## Requirements in the remainder of this section apply where a liner is selected.
+
+## The liner material shall be as indicated in the datasheet.
+
```datasheet
−label: Underdrain pipe
+label: Liner Material
+type: select
+options:
+ - "High-density polyethylene geomembrane per GRI GM13"
+ - "Linear low-density polyethylene geomembrane per GRI GM17"
+ - "Polyvinyl chloride geomembrane per ASTM D7176"
+ - "Reinforced polypropylene geomembrane"
+```
+
+## HDPE is the stiffest and the most chemically resistant of the four and the least forgiving of a rough subgrade or a tight corner, so it is fusion-welded by a specialty installer and specified where the discharge is regulated; LLDPE conforms to the excavation and the underdrain trench and is seamed in the field with the same equipment at a lower stiffness; PVC conforms best and seams with solvent or heat by a general crew, with a lower resistance to hydrocarbons from the pavement above; and reinforced polypropylene carries a scrim that resists the puncture of the stone placed on it and is specified where the cushion geotextile alone is judged marginal. {note}
+
+## The liner thickness shall be as indicated in the datasheet.
+
+```datasheet
+label: Liner Thickness
+type: range
+unit: mil
+min: 20
+max: 60
+setpoints: [20, 30, 40, 60]
+constraint: min
+```
+
+## The liner shall be protected by a cushion geotextile furnished under [[sync/geosynthetics]] on each face where reservoir stone bears on it, and the subgrade beneath it shall be free of stones larger than 3/8 in., roots, and sharp projections.
+
+## The liner shall extend up the excavation face to the elevation shown on the pavement section details and shall be sealed to the underdrain outlet pipe and to every other penetration with the manufacturer's pipe boot or a mechanical batten with a gasket.
+
+## Field seams shall be made by the method the liner manufacturer publishes for the material, every seam shall be tested nondestructively over its full length by air pressure per ASTM D5820 for a dual-track fusion seam or by vacuum box for every other seam, and a seam that fails shall be repaired and retested before the cushion geotextile is placed.
+
+## A lined reservoir below [[parameter: seasonal-high-groundwater-elevation]] shall not be left empty before the reservoir stone is in place, and the Contractor shall maintain dewatering under [[sync/earthwork]] until it is.
+
+## A lined reservoir weighs almost nothing when it is empty, and a liner that floats before the stone is placed folds, tears at its seams, and has to be removed; the stone is the ballast, and the sequence that places it the same day the liner is tested is what keeps the liner down. {note}
+
+# Underdrains and Outlet Control {toc}
+
+## An underdrain shall be provided within the reservoir as indicated in the datasheet.
+
+```datasheet
+label: Underdrain within the Reservoir
type: radio
options:
− - Perforated (partial / no infiltration)
− - Solid outlet pipe only
− - None (full infiltration)
−default: Perforated (partial / no infiltration)
+ - "Perforated underdrain in the reservoir bottom"
+ - "No underdrain"
+derived: "the hydrologic mode, an underdrain where partial or no infiltration is selected and none where full infiltration is selected"
+default: derived
```
+## Requirements in the remainder of this section apply where an underdrain is provided.
+
+## Underdrain Pipe {toc}
+
+### Underdrain pipe shall be perforated pipe of the material indicated in the datasheet, laid in the reservoir stone with the perforations down and without a pipe sock or a filter wrap.
+
```datasheet
−label: Underdrain pipe diameter
+label: Underdrain Pipe Material
type: select
−unit: in
options:
− - '4'
− - '6'
− - '8'
−default: '6'
+ - "Perforated corrugated polyethylene per AASHTO M 252 or AASHTO M 294"
+ - "Perforated PVC drain pipe per ASTM D2729"
+ - "Perforated PVC sewer pipe per ASTM D3034"
```
+### Corrugated polyethylene is the lightest, the cheapest, and the easiest to lay in a stone bed, and its corrugated interior holds sediment and resists a jetting nozzle; ASTM D2729 PVC is a thin-walled smooth pipe that cleans easily and is the drain pipe most paver-industry guidance names; and ASTM D3034 PVC is a sewer-wall pipe specified where the underdrain runs under a truck loading area, where it is jetted on a schedule, or where the local sewer authority's standard details call for it. {note}
+
+### The underdrain diameter shall be as indicated in the datasheet.
+
```datasheet
−label: Raised outlet — water held above subgrade (partial infiltration)
+label: Underdrain Pipe Diameter
type: range
unit: in
−min: 6
+min: 4
max: 12
+setpoints: [4, 6, 8, 10, 12]
+drawing_ref: "the underdrain plan and profile on the civil drawings"
+default: deferred
+constraint: exact
+```
+
+### Underdrain layout, inverts, and slopes shall be as shown on [[drawing: the underdrain plan and profile]], and the Contractor shall survey the inverts before the pipe is covered.
+
+### A cleanout shall be provided at the upstream end of every underdrain run and at every change of direction, extended to the finished surface with a cap set flush, so that the run can be rodded or jetted from the surface.
+
+### The underdrain shall discharge to the storm sewer, inlet, or downstream stormwater facility shown on the drawings through the connection and the invert specified under [[sync/storm-drainage]].
+
+## Raised Outlet and Drawdown {toc}
+
+### Where the hydrologic mode is partial infiltration, the underdrain outlet shall be raised so that water is held in the reservoir above the subgrade to the height indicated in the datasheet before it discharges.
+
+```datasheet
+label: Raised Outlet Height above the Reservoir Bottom
+type: range
+unit: in
+min: 0
+max: 24
step: 1
−default: 9
+drawing_ref: "the stormwater management report and the outlet detail on the civil drawings"
+default: deferred
+constraint: exact
```
+### The raised outlet shall be formed by an upturned elbow or a weir in an accessible outlet structure, and not by a bend buried in the stone.
+
+### The raised outlet sets the depth of water that waits on the subgrade and the depth that leaves through the pipe, so it is the dimension that divides the storm between infiltration and release; an outlet formed in a buried bend cannot be inspected, adjusted when the measured rate differs from the design, or cleaned, and every design manual that credits partial infiltration asks to see it. {note}
+
+### The reservoir shall drain from full to empty, through infiltration and the underdrain together, within the time indicated in the datasheet.
+
```datasheet
−label: Reservoir drawdown time
+label: Reservoir Drawdown Time
type: range
unit: hr
min: 24
max: 72
−step: 12
−default: 48
+setpoints: [24, 48, 72]
+derived: "the drawdown time the governing stormwater design manual requires for a permeable pavement"
+default: derived
+constraint: max
```
−## Impermeable Liner {toc}
+### A reservoir that has not emptied before the next storm stores only the part of its volume that is empty, and a subgrade that stays saturated loses the bearing the structural design counted on; the drawdown time is a firm limit in every design manual, and the raised outlet height, the orifice, and the subgrade rate are what the civil engineer of record adjusts to meet it. {note}
−## In no-infiltration mode an impermeable liner isolates the reservoir from the subgrade so that all captured water leaves through the underdrain rather than infiltrating; the liner is used over contaminated, expansive, or otherwise unsuitable subgrades. {note}
+### Where an overflow or a bypass is shown for the pavement cell, it shall be set at the elevation shown on the drawings and shall discharge to the storm sewer under [[sync/storm-drainage]].
−## In no-infiltration mode, an impermeable liner shall be installed at the base and up the sides of the reservoir excavation, with all seams sealed continuous and watertight.
+# Edge Restraints {toc}
−## The liner shall be protected from puncture by a cushion geotextile above and below where it bears on or is covered by angular reservoir stone.
+## Every edge of a paver or grid paver pavement shall be restrained as indicated in the datasheet, and the restraint shall bear on the base course and not on the bedding.
```datasheet
−label: Impermeable liner (no-infiltration mode)
−type: radio
+label: Paver Edge Restraint
+type: select
options:
− - HDPE geomembrane
− - Reinforced flexible membrane
− - Not applicable (infiltration mode)
−default: Not applicable (infiltration mode)
+ - "Cast-in-place concrete curb or curb and gutter"
+ - "Precast concrete curb"
+ - "Cut stone curb"
+ - "Metal or plastic edge restraint spiked into the base course"
+ - "Existing structure, wall, or pavement edge"
```
−# Geometry and Slopes {toc}
+## A cast-in-place curb is the restraint of nearly every vehicular paver pavement, because it is placed before the base and the pavers are laid against it, and it is built under the concrete paving standard; a precast curb is set on a concrete haunch and suits a site that cannot wait for a cast-in-place cure; a cut stone curb is the restraint where the finish schedule calls for it; a spiked metal or plastic restraint holds a pedestrian pavement and is the only restraint that can follow a curve tightly, and it is lifted by frost and by a wheel that rides over the edge, so ASCE 68 keeps it off vehicular work; and an existing structure or pavement edge restrains where the pavers meet one. {note}
−## A minimum surface slope keeps an alternate drainage path available if the surface partially clogs, while a maximum slope keeps water from running off the surface and bypassing the reservoir before it can infiltrate. {note}
+## Where the restraint is a concrete curb, the curb shall be constructed under [[sync/concrete-paving]] with its back face vertical for the full depth of the bedding and surface course, and the gap between the curb and the first paver shall not exceed the joint opening.
−## The finished surface shall slope a minimum of 1% to maintain a positive overland drainage path if surface infiltration is reduced by clogging.
+## Pervious concrete and porous asphalt need no edge restraint for their own stability, and an edge against landscape shall be formed with a thickened edge or a curb as shown on [[drawing: the pavement edge details]], so that the adjoining soil does not wash into the voids.
−## The finished surface slope shall not exceed 5% for PICP.
+# Inspection and Maintenance Provisions {toc}
−## The finished surface slope shall not exceed 3% to 5% for pervious concrete and porous asphalt, as shown for the project.
+## The pavement shall be furnished with the inspection and maintenance provisions indicated in the datasheet.
−## On sloped sites, the reservoir base shall be terraced or check-dammed so that stored water is retained across the slope rather than draining laterally to the low end.
+```datasheet
+label: Inspection and Maintenance Provisions
+type: checkbox
+options:
+ - "Observation well to the reservoir bottom in each pavement cell"
+ - "Cleanout at each underdrain run"
+ - "Access cover on the outlet structure"
+ - "Permanent marker or sign identifying the permeable pavement and the maintenance it requires"
+default: ["Observation well to the reservoir bottom in each pavement cell", "Cleanout at each underdrain run"]
+constraint: all_of
+```
−## Edge restraints shall be provided at all PICP and grid-paver perimeters to resist lateral creep of the units and joint-fill loss under traffic.
+## An observation well is a perforated riser standing on the reservoir bottom and capped flush with the surface, through which the Owner reads how far the reservoir has drained a day after a storm; it is the only instrument that distinguishes a clogged surface from a clogged subgrade, and most stormwater permits require one per cell. The sign is the device that stops a future contractor from sealcoating the surface or a future owner from sanding it. {note}
−## Surface grades, slope directions, and the limits of the permeable pavement shall be shown on the drawings. [[drawing: paving plan and grades]]
+## Each observation well shall be a perforated pipe not less than 4 in. in diameter, set vertically on the reservoir bottom, with a lockable cap set flush with the finished surface and its location recorded on the record drawings.
−```datasheet
−label: Surface slope
−type: range
−unit: '%'
−min: 1
−max: 5
−step: 0.5
−default: 1.5
−```
+## The locations of observation wells, cleanouts, and the outlet structure shall be as shown on [[drawing: the underdrain plan]].
−# Testing {toc}
+# Installation {toc}
−## Acceptance testing confirms that the as-built surface actually infiltrates at the design rate; surface infiltration is the property that degrades in service and the one the owner will re-test over the system's life, so it is the primary acceptance metric. {note}
+## Sequencing and Sediment Protection {toc}
−## Pervious concrete surface infiltration shall be tested in place per ASTM C1701 and shall meet or exceed the specified minimum (commonly 100 in/hr).
+### A permeable pavement cell shall not be excavated to the reservoir subgrade until every area that drains to it has been permanently stabilized, or until the runoff from every unstabilized area has been diverted around the cell under [[sync/erosion-and-sediment-control]].
−## PICP and concrete grid paver surface infiltration shall be tested per ASTM C1781 and shall meet or exceed the specified minimum (commonly 100 in/hr).
+### The surface course shall be placed as the last paving operation in the area it serves, after the adjoining pavements, curbs, utilities, and landscape grading are complete, unless the Engineer of Record accepts a different sequence in writing with the protection it requires.
−## Pervious concrete void content shall be tested on extracted cores or molded specimens per ASTM C1754 and shall fall within the specified range.
+### Where a completed reservoir or surface must remain exposed before the contributing area is stabilized, the Contractor shall protect it from sediment-laden runoff with a diversion berm, a silt fence set outside the edge restraint, or a geotextile cover over the reservoir, and shall remove the protection only when the contributing area is stabilized.
−## Infiltration acceptance tests shall be performed at the frequency set for the project, distributed across the pavement area rather than clustered.
+### Construction equipment, haul trucks, and material deliveries shall not cross the completed surface, and no soil, mulch, or construction material shall be stockpiled on it.
−## A distributed sampling plan is required because tests clustered in one clean location can mask a clogged zone elsewhere. {note}
+### Sediment-laden runoff that reaches a completed reservoir before the surface is placed shall be removed, and where the stone has been contaminated the Contractor shall remove and replace the contaminated stone at the Contractor's expense.
−## Any test location that fails the minimum infiltration rate shall be remediated by vacuum cleaning and re-tested, and shall be removed and replaced if it still fails.
+### Sediment that reaches a completed surface before acceptance shall be removed by vacuum sweeping before it is tracked into the voids, and the surface shall be tested again for infiltration where the Engineer of Record directs.
−```datasheet
−label: Surface infiltration acceptance method
−type: radio
−options:
− - ASTM C1701 (pervious concrete)
− - ASTM C1781 (PICP / grid pavers)
−default: ASTM C1781 (PICP / grid pavers)
−```
+### The reservoir is open storage for the whole period it is exposed, and the construction site around it is the dirtiest its contributing area will ever be; a permeable pavement built first and used as the haul road is clogged before the certificate of occupancy, and the failure is charged to the product. {note}
+## Subgrade Excavation and Protection {toc}
+
+### Excavation to within 12 in. of the reservoir subgrade elevation shall be made under [[sync/earthwork]], and the final 12 in. shall be excavated under this standard, with equipment working from outside the cell or from stone already placed, immediately before the geotextile, liner, or reservoir stone is placed.
+
+### An infiltration subgrade shall not be proof-rolled, compacted, or driven on by rubber-tired or tracked equipment, and the proof rolling and compaction that [[sync/earthwork]] requires of a pavement subgrade shall not be applied to it.
+
+### Where the hydrologic mode is no infiltration, the subgrade beneath the liner shall be compacted and proof-rolled as a pavement subgrade under [[sync/earthwork]] before the liner is placed.
+
+### Where an infiltration subgrade has been smeared, compacted, or sealed by equipment or by rain, the surface shall be scarified to a depth of 3 in. with a toothed bucket or a rake and the loosened soil left in place before the stone is placed.
+
+### The subgrade is prepared to pass water, not to carry a roller: a clay subgrade smeared by a bucket or rolled by a loaded truck closes to a fraction of its measured rate, and the pavement built on it then behaves as a lined section with no outlet. {note}
+
+### The excavated subgrade shall be released at the hold point before any geotextile, liner, or stone is placed, and where a subgrade has stood exposed for more than one working day, or has received runoff, the Engineer of Record may require the infiltration test to be repeated at the Contractor's expense before release.
+
+### Where the finished subgrade of an infiltrating section fails the infiltration rate the design rests on, the Contractor shall report the result to the Engineer of Record, and the Engineer of Record shall direct remediation, conversion to partial or no infiltration, or a revised reservoir, with the cost borne by the Contractor where the failure results from compaction or contamination of the subgrade during construction.
+
+## Surface Grades and Slopes {toc}
+
+### The finished surface shall be graded to the elevations and slopes shown on [[drawing: the grading plan]], and shall not slope more than 5 percent unless the reservoir beneath it is terraced as this standard requires.
+
+### The finished surface shall drain to its own voids and joints, and no area shall hold water deeper than 1/4 in. an hour after rain, and no area of ponding shall occur within an accessible parking space, access aisle, or accessible route.
+
+### Accessible parking spaces, access aisles, and accessible routes across the pavement shall be finished within the slope limits of the adopted accessibility standard, and the Contractor shall verify the finished slopes at each space and aisle before the surface is released for marking.
+
+### The finished surface shall be flush with every adjoining pavement, curb, drainage structure, and cleanout cap, within 1/4 in., so that a vacuum sweeper passes over the edge without lifting.
+
+# Testing and Acceptance {toc}
+
+## Surface Infiltration {toc}
+
+### The surface infiltration rate of the completed pavement shall be measured in accordance with ASTM C1701/C1701M for pervious concrete and porous asphalt, and in accordance with ASTM C1781/C1781M for permeable interlocking concrete pavers and grid pavers, and shall be not less than the rate indicated in the datasheet at every test location.
+
```datasheet
−label: Minimum acceptance surface infiltration rate
+label: Surface Infiltration Acceptance Rate
type: range
unit: in/hr
min: 50
−max: 200
−step: 10
+max: 500
+setpoints: [50, 100, 150, 200, 300, 500]
default: 100
+constraint: min
```
+### A new permeable surface infiltrates at several hundred inches per hour, and the acceptance rate is set well below that, because the surface rate is the property that falls in service and the number in the datasheet is the margin the Owner starts with; 100 in/hr is the acceptance most design manuals and manufacturers name and is an order of magnitude above any rainfall, a lower rate is accepted for a grid or turf surface, and a higher rate is set where the design manual tests the surface at acceptance against the rate it credits and the Owner wants the sweeping interval to start long. {note}
+
+### Surface infiltration tests shall be performed at not fewer than one location for each area of pavement indicated in the datasheet, at not fewer than three locations in each cell, at locations the testing agency selects and distributes across the cell, after the pavement is complete and before it is opened to traffic.
+
```datasheet
−label: Infiltration test frequency
−type: select
−options:
− - 1 per 5,000 ft2
− - 1 per 10,000 ft2
− - 1 per 15,000 ft2
−default: 1 per 10,000 ft2
+label: Pavement Area per Surface Infiltration Test
+type: range
+unit: ft²
+min: 2500
+max: 25000
+setpoints: [2500, 5000, 10000, 15000, 25000]
+constraint: max
```
−# Installation {toc}
+### A closer test spacing finds the low corner of a cell that a single test in the middle of it misses, at the cost of a technician's day per cell; one test per 5,000 to 10,000 ft² is the usual setting on site work, the close interval is set where the pavement is small and the whole of it is a few tests, and the wide interval where the state design manual sets its own sampling and that sampling applies. {note}
−## Construction Sequencing {toc}
+### Where a test location fails the acceptance rate, the Contractor shall vacuum-sweep the area around it, the location shall be retested at the Contractor's expense, and a location that fails the retest shall be removed and replaced to the limits the Engineer of Record directs, at the Contractor's expense.
−## The reservoir base is uncovered storage for the entire construction period, and any sediment that washes into it clogs the voids permanently; protecting the surface and the open base until upgradient disturbance is stabilized is the difference between a working system and a failed one. {note}
+### The testing agency shall record the location, the method, the water volume, the time, and the computed rate of every test, passing and failing, and the Contractor shall not replace a failing report with the report of a later passing test.
−## Permeable pavement shall not be placed until all upgradient soil disturbance contributing run-on to the pavement is permanently stabilized.
+## Pervious Concrete Density, Void Content, and Thickness {toc}
−## Sediment-laden construction runoff shall be prevented from flowing across the completed permeable surface or into the open reservoir base by temporary protection such as straw wattles, silt fence, or geotextile covers.
+### The fresh density of pervious concrete shall be tested in accordance with ASTM C1688/C1688M on the first three loads of each placement day and on every fifth load thereafter.
−## Final surface course installation shall be deferred until the surrounding site is stabilized, where the construction sequence allows.
+### Not fewer than three cores shall be taken from each 5,000 ft² of pervious concrete, or fraction of it, placed on a day, not sooner than 7 days after placement, and tested in accordance with ASTM C1754/C1754M for hardened density and void content and measured for thickness.
−## Equipment shall not track soil onto the reservoir base or the finished surface; any tracked sediment shall be removed by vacuum sweeping before it is worked into the voids.
+### The average void content of each set of cores shall be within 3 percentage points of the design void content, and the thickness of each core shall be not less than the thickness in the datasheet less 1/4 in.
−## Subgrade Preparation {toc}
+### A placement whose cores fall outside the void content tolerance or below the thickness limit shall be evaluated by the Engineer of Record, who may accept it at an adjusted price, require additional cores at the Contractor's expense to bound the deficient area, or require removal and replacement.
−## The subgrade is prepared to receive and pass water, not to be sealed; over-compaction or rubber-tired rolling of the subgrade smears the soil surface and destroys the very infiltration the system depends on. {note}
+### Core holes shall be filled with pervious concrete of the project mixture the same day the core is taken.
−## The subgrade shall be excavated to grade with equipment that does not over-compact the infiltrating surface, and shall not be proof-rolled with rubber-tired equipment in infiltration modes.
+## Drawdown Observation {toc}
−## The exposed subgrade shall be protected from sedimentation and from compaction by construction traffic until the geotextile or reservoir stone is placed.
+### Where an observation well is provided, the Contractor shall record the water level in each well at 24 hours and at 48 hours after the first storm of 0.5 in. or more that follows completion, and the reservoir shall have drained to the raised outlet elevation, or to empty where there is none, within the drawdown time in the datasheet.
−## Where the subgrade has been smeared or compacted, it shall be scarified to restore infiltration before placing the overlying layers, except where an impermeable liner is specified.
+### Where the reservoir has not drained within the drawdown time and the surface infiltration tests have passed, the Contractor shall report the condition to the Engineer of Record, who shall determine whether the cause is the subgrade, the outlet, or construction, and the cost of the correction shall be borne by the Contractor where the cause is compaction or contamination of the subgrade or a defect in the underdrain or outlet.
−## Maintenance Access {toc}
+## Final Acceptance of the Pavement {toc}
−## Post-construction inspection and the cleaning that keeps the surface infiltrating both depend on physical access to the reservoir and the outlet; many MS4 permits require this access to be built in, and a system with no observation point cannot be documented as functioning. {note}
+### Final acceptance of the permeable pavement shall require passing results at every surface infiltration test location, pervious concrete cores within tolerance where that surface is used, the drawdown observation where an observation well is provided, the record drawings, the operation and maintenance manual, the turnover cleaning, and the recorded maintenance agreement where the stormwater permit requires one.
−## Cleanout risers shall be provided on underdrain runs and brought to the surface for rodding and inspection.
+### Acceptance shall not waive the Contractor's warranty obligations or the Contractor's liability for latent defects.
−## At least one observation well shall be provided per pavement cell to monitor the reservoir water level and confirm drawdown.
+# Maintenance Turnover {toc}
−## The outlet control structure shall be accessible for inspection and maintenance.
+## The permeable surface and the joints shall be vacuum-swept, every cleanout and observation well shall be flushed and capped, and the outlet structure shall be cleaned of construction sediment before the surface infiltration acceptance tests are performed and again at turnover where the pavement has been in use between the two.
−## Maintenance-access locations — cleanouts, observation wells, and the outlet control structure — shall be shown on the drawings. [[drawing: maintenance access locations]]
+## The operation and maintenance manual shall state a vacuum sweeping schedule of not fewer than two sweepings per year, one after the winter season and one after leaf fall, with a regenerative-air or vacuum sweeper and not a mechanical broom sweeper, and additional sweepings wherever the observation well or a surface test shows the rate falling.
−```datasheet
−label: Maintenance access provisions
−type: checkbox
−options:
− - Underdrain cleanout risers
− - Observation well per cell
− - Accessible outlet control structure
−default:
− - Underdrain cleanout risers
− - Observation well per cell
− - Accessible outlet control structure
−```
+## The operation and maintenance manual shall state the observation well reading procedure and the drawdown time, the surface infiltration retest method and the rate at which cleaning is triggered, the joint fill top-up procedure and gradation for a paver surface, the prohibition on sealcoating, overlay, sand, and abrasives, and the repair procedure for a utility cut through the section.
−# Maintenance {toc}
+## The Contractor shall record the surface infiltration rate at every acceptance test location and the observation well readings at turnover, and that record shall be the baseline from which the Owner's first cleaning interval is measured.
−## Permeable pavement is a stormwater BMP with a service obligation, not a one-time installation; the dominant failure mode in service is gradual surface clogging from sediment and debris, and scheduled vacuum sweeping is what preserves the design infiltration rate over the system's life. {note}
+## A permeable pavement is a stormwater practice with a maintenance obligation attached to the property, and the party that sweeps it is the party that keeps the permit; the manual is written for a maintenance crew that has never seen the section, and the baseline rate is what lets a reading a year later be judged. {note}
−## The surface shall be vacuum swept a minimum of twice per year — after the spring sanding season and in the fall — and more frequently where sediment loading is high.
+# Delivery, Storage, and Handling {toc}
−## Sanding for winter traction shall be followed by vacuum sweeping promptly after each application event to recover joint and surface infiltration.
+## Washed stone for every layer shall be delivered from the certified source, shall be stockpiled on a clean, hard, drained surface separated from soil and from every other aggregate, and shall not be stockpiled on the subgrade or on a completed layer of the section.
−## The operation and maintenance manual shall record the sweeping schedule, the observation-well drawdown check procedure, and the surface infiltration re-test method so the owner can verify continued performance.
+## A stockpile that has been contaminated by soil, by runoff, or by another aggregate shall not be used in the section, and the Engineer of Record may require a gradation and fines test on any stockpile before it is placed.
−```datasheet
−label: Minimum vacuum sweeping frequency
−type: select
−options:
− - 2 times per year
− - 3 times per year
− - 4 times per year
−default: 2 times per year
−```
+## Washing removes the fines at the quarry, and a stockpile on bare ground or under a runoff path puts them back; aggregate cleanliness is the property most easily lost between the quarry and the reservoir and the one no later test on the completed pavement can restore. {note}
−# Delivery, Storage, and Handling {toc}
+## Paving and grid units shall be delivered banded on pallets, stored on a hard surface, and protected from soil, mortar, and mud before placement.
−## Aggregate cleanliness is the property most easily lost between the quarry and the reservoir; stockpiling washed stone on bare ground or letting it sit under runoff reintroduces the fines that the washing removed. {note}
+## Geotextile and liner rolls shall be stored off the ground and covered where they will remain on site longer than the exposure period the manufacturer publishes, and shall be handled so that the rolls are not torn or punctured.
−## Washed bedding, joint-fill, and reservoir aggregate shall be delivered clean and shall be stockpiled on a clean, hard, well-drained surface, separated from soil and from other aggregates.
+## Pervious concrete shall be delivered in accordance with ASTM C94/C94M, with the batch time on every ticket, and porous asphalt shall be sampled in accordance with ASTM D979/D979M and delivered in covered trucks at the temperature the job-mix formula states.
−## Paving units shall be delivered banded on pallets and stored to prevent chipping and contamination of the units before placement.
+# Warranty {toc}
−## Geotextile and liner materials shall be stored protected from prolonged ultraviolet exposure and from puncture before installation.
+## The Contractor shall warrant the permeable pavement against defects in materials and workmanship for the period indicated in the datasheet, beginning at substantial completion.
−# Warranty {toc}
+```datasheet
+label: Permeable Pavement Warranty Period
+type: range
+unit: years
+min: 1
+max: 5
+setpoints: [1, 2, 3, 5]
+default: 1
+constraint: min
+```
−## Early clogging traceable to construction sediment or defective materials is the Contractor's responsibility rather than the owner's maintenance burden. {note}
+## One year from substantial completion is the period most site civil work carries and the one in which a section built wrong shows it, through its first winter and its first wet season; a longer period is set where the stormwater permit or a municipality that will accept the pavement requires it, or where the Owner wants the installer answerable through the second season that a subgrade takes to prove its rate. {note}
−## The warranty shall cover defects in materials and workmanship and shall include the as-placed surface infiltration performance.
+## The warranty shall cover raveling of pervious concrete or porous asphalt, loss of joint fill or creep of pavers beyond the lippage and straightedge limits of this standard, settlement of the surface over the reservoir or over the underdrain trench, displacement of an edge restraint, a liner that leaks, an underdrain or outlet that does not drain, and a surface infiltration rate at any acceptance test location that falls below the acceptance rate in the datasheet within the warranty period where the Owner has performed the sweeping the operation and maintenance manual requires.
−## The Contractor shall warrant the permeable pavement against defects in materials and workmanship for the period specified for the project, and in no case less than 1 year.
+## The warranty shall not cover loss of infiltration attributable to sediment delivered from the contributing area after acceptance, to winter sand or abrasives, to a sealcoat or overlay applied by others, to a utility cut through the section after substantial completion, or to loads exceeding the design traffic class in the datasheet.
−## The Contractor shall warrant that the surface infiltration rate measured at substantial completion is maintained, excluding reductions caused by owner failure to perform the specified maintenance.
+## Where the parties disagree whether a loss of infiltration is attributable to construction or to a cause after acceptance, the Engineer of Record shall make the initial determination, and the observation well record and the baseline rate at turnover shall be the evidence considered first.
−```datasheet
−label: Warranty period
−type: select
−options:
− - 1 year
− - 2 years
− - 5 years
−default: 2 years
−```
+## Where the Contractor repairs or replaces work under the warranty, the repaired work shall carry a warranty running from the date of the repair for the full warranty period or for the remainder of the original period, whichever ends later.
+## The Contractor shall bear the cost of the warranty repair, of the markings restored over it, and of the restoration of adjoining pavement and landscape disturbed by it.
+
+## The warranty does not limit the Owner's remedies for a sand bedding, a contaminated reservoir, a compacted subgrade, or an untested liner seam that is concealed by the surface course and discovered after the warranty period.
+
# Spare Parts {toc}
−## Replacement of individual clogged or damaged units is part of normal PICP and grid-paver maintenance, so a small attic stock of matching units lets the owner repair locally without re-tendering and without a color or texture mismatch. {note}
+## For a paver or grid paver pavement, the Contractor shall deliver attic stock of full units of each type, color, and thickness used, in the quantity indicated in the datasheet, palletized and stored where the Owner directs.
−## For PICP and concrete grid paver projects, the Contractor shall deliver attic stock of each paver unit type, color, and thickness used, in the quantity specified for the project.
+```datasheet
+label: Paver Attic Stock
+type: range
+unit: '% of installed units'
+min: 0
+max: 5
+step: 1
+constraint: min
+```
+## The Contractor shall furnish the attic stock indicated in the datasheet with the closeout submittals.
+
```datasheet
−label: Paver attic stock
−type: select
+label: Attic Stock Furnished
+type: checkbox
options:
− - 1% of installed units
− - 2% of installed units
− - 3% of installed units
−default: 2% of installed units
+ - "Paving or grid units of each type, color, and thickness"
+ - "Joint fill stone of the specified gradation, not less than 1 ton"
+ - "One spare cap for each observation well and cleanout"
+default: ["Paving or grid units of each type, color, and thickness", "Joint fill stone of the specified gradation, not less than 1 ton"]
+constraint: all_of
```
+
+## A utility cut through a paver pavement is repaired by lifting the units and relaying them, and the units lost to the saw are replaced from the attic stock in the same color run; a stock of the joint fill lets the Owner top up the joints after the first season's sweeping without finding a source for a ton of washed No. 8 stone. {note}