nrmca pervious concrete construction checklist

NRMCAPERVIOUS CONCRETECONSTRUCTONCHECKLISTS

Appendix A: Checklists

Pervious Concrete

This publication provides forms and checklists that can be useful to the pervious concrete contractors and concrete suppliers on projects. Some of these checklists are extensive and users are encouraged to shorten these suggested checklists to suit their project needs. Some shorter form checklists are suggested here. The important point is such project planning tools should be used. Certified pervious concrete contractors or other individuals should use these forms and checklists and modify them as appropriate to local practice and to specific projects. In some cases space is provided to identify responsibilities of persons on a project. It is important to establish these responsibilities prior to the project.

NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE

Project Information and Responsible Parties

Project name

Location/Address

Project start date

Project completion date

Project participants

Owner Contact

Email Phone Cell:

Designer/Architect Contact

Email Phone Cell:

Construction ManagerGeneral Contractor

Contact

Email Phone Cell:

Pervious Concrete Contractor

Contact

Email Phone Cell:

Concrete Producer Contact

Email Phone Cell:

Inspection/Testing Agency

Contact

Email Phone Cell:

Other Contact

Email Phone Cell:

Background information and unique features about the project: Include area and volume of concrete


Suggested Schedule for Pervious Concrete ProjectsSubmittals and Action Items Due Bid Documents 3 months prior Specifications and Shop Drawings Pavement sections and layout Joint Layout Testing requirements and frequency

6 weeks prior As directed by engineer

Contractor qualifications Training program beyond that used for certification Requirement for certified personnel level and numbers needed and

verification List previous projects

At contract signing Submitted with bid

Pervious Concrete Mixtures Aggregate type and size Mixture density and calculated voids List previous projects where mixtures have been used

4 weeks prior

Testing/Inspection Agency Requirements confirm experience with pervious concrete and awareness of tests specific to

pervious concrete

2 weeks prior

Test panel placement and test results Density of fresh concrete (5 lb/cu.ft. [80 kg/m3] of specified value) Cores for thickness and density (per test panel per project specification) Average thickness (+1.5-inch and -1/4-inch) [+38 mm and -6 mm] Core density recorded for project acceptance Visually inspected: written approval Finished surface and jointing appearance Permeability adequate draining

Placement: 3 weeks prior Results: at least 1 week prior

Tests during construction (if required): Sampling in accordance with ASTM C172 Density of fresh concrete (5 lb/cu.ft. [80 kg/m3] of specified value) Cores for thickness and density (3 per 5000 sq.ft. [470 m2]) Average thickness (+1.5-inch and -1/4-inch) [+38 mm and -6 mm] Core density (5% of test panel density)

Pre-placement Notification Architect/Engineer

48 hours prior to placement

Pre-construction jobsite visit and approval Final subgrade/base preparation inspection Base material meets specification Base moisture and temperature control Pervious equipment checklist Joint detail physically marked on forms Curing plastic sheets and anchors onsite and ready

24 hours prior 12 hours and just prior to pour


Considerations by DesignerGoal: Design and specification to consider structural, hydrological and appearance

Item Responsibility Notes Pre-design site visit Soil characteristics - native permeability, preconstruction

rainfall characteristics

Base storage thickness matched with permeability of soil and design storm storage

Sloping terrain considered

Cut and fill requirements; requirements for fill

Sediment run-on isolated or redirected away from pavement

Check dams/cutoff walls to contained volume and velocity if slopes are steep or long

Run-on from adjacent pavement, sidewalks and roofs

Landscaping - schedule and sequencing

Earth mounds replaced with swales

Bark dust replaced with less damaging ground cover Design parameters Native soil infiltration

Soil moisture sensitivity swelling or frost heave - water table level

Surrounding conditions and drainage potential

Rainfall intensity, anticipated volume and storm event for design of system

Freeze-thaw conditions - review base thickness design requirements

Traffic loading

Pedestrian use and ADA compliance Drawings and Specification

Reviewed in accordance with ACI 522.1

Approved pervious concrete mixture requirements

Review qualifications of contractors and on site supervision

Select testing/inspection agency and establish responsibility

Establish schedule and tests for test panel

Approve test and appearance of test panel Sub Base and Sub Grade Control

Verify grades and layout of pavement and surroundings

Verify elevations (thickness) and materials as per specification. Verify permeability of subgrade and base prior to pavement installation


Item Responsibility Notes

Verify location of embedded items, vents and drains

Ensure responsibility for moisture and temperature management of subgrade and base presoak subgrade 2 - 18 hours before pour; moisten base prior to pour

Placement Detail Pour layout joint spacing marked 15 feet [4.6 m], 20 feet [6.1 m] max; square panels

Jointing methods and timing. Confirm compaction of edges

Box-out detail for vents/manholes

Jointing curves - do not joint to a point Testing/Inspection Verify certifications

Define tests and frequency

Responsibility of testing/inspection

Addressing weather conditions temperature, humidity, wind, precipitation

Compliance with method and duration of curing

Post installation testing and acceptance


Considerations for Site-work ContractorGoal: Prepare site-work on schedule to ensure proper application of pervious pavement

Item Responsibility Notes Vegetation Vegetation and related debris removed from project area

Trees and shrubs pruned to reduce debris on pavement

Protect identified trees and related root system Site grade work Slopes and grades to ensure minimizing water flow onto

pavement

Removal and replacement of soft or bad spots

Cut and fill to achieve required elevations and slopes

Subgrade material complies with specifications Subgrade and base preparation

Subgrade at proper elevation and at uniform compaction

Permeability of subgrade not impacted by compaction

Base material as per specification

Base installed to specified thickness followed by proof rolling

Approval by engineer of record Filter fabric Installed as per specification - required on clay soils and

sloped grade

Overlap of 16 inches [400 mm] each pass

Installed with check dams as per specification

Choker course alternative to filter fabric Grade check Compaction of base complete before final grade check

Verify finished base elevation and slope before installing pavement

Isolation Installation of impermeable liner as required by specification

Installation of isolation material between pavement and adjoining elements

Alternatives as appropriate.


Considerations for Ready Mixed Concrete Producer(Detailed Form)

Goal: to develop mixture and produce and deliver to meet contractors needs

Item Responsibility Notes Specification and contractor needs

Obtain and review copy of project specification

Establish delivery schedule relative with contractor

Confirm contractor experience

Tools and method of installation used by contractor

Truck spacing: Haul distance and route consider traffic delays, project access and staging

Monitor weather conditions

Identify jobsite contact and phone number/radio Verify Aggregate Characteristics Use of sand

Dry-rodded unit weight and voids of aggregate

Check aggregate grading and cleanliness

Void content of aggregate should ideally be between 38 and 42%

Consider use of sand with voids exceeding 42%

With voids under 38% steps to reduce paste to achieve at least 18% voids in pervious mixture

Aggregate storage and handling

Consider isolating stockpile of aggregate for pervious mixtures

Ensure adequate supply for job, build stockpile uniformly

Control stockpile segregation, moisture and contamination

Measure and control aggregate moisture avoid pools around stockpiles, consider covering stockpiles until used

Loading aggregates

Ensure proper stockpile extraction and loading Work the whole face of stockpile to ensure uniform grading is placed in bins or belts

Minimize contamination when building and working stockpiles

Do not mix aggregates with different moisture conditions

Load stockpiles in bins verified to be empty and free of contamination

Pervious Concrete Mixture

Review specification requirements Develop and test pervious concrete mixture and establish optimum cement, water and admixture ranges

Measure density of fresh pervious mix and calculate voids report to design professional of record and parties as required


Item Responsibility Notes

If specification does not address density or void content, target voids for fresh pervious concrete is generally 203%

Batching Ensure designated mixture is in batch computer Verify required aggregate in storage/batching bins

Ensure adequate capacity of bins and weigh batchers

Ensure adjustments for aggregate moisture are addressed

Ensure only cold water is used as mixing water

Schedule trucks typically used for curb mixes

Ensure trucks are empty and clean

Ensure truck saddle tanks store cold water

Batch first load in halves. Inspect 1st half and make water adjustments for second half Verify correct product identification Monitor headwater or batching rate to minimize balling. Batch with as much water as possible after first load is adjusted properly DO NOT hold back water for jobsite re-tempering Make pro-rated adjustments to batches if ingredients are out of tolerance Verify batch capacity and yield

Dispatch Verify truck scheduling on day of pour Schedule trucks that can better discharge low slump loads for pervious project

Maintain constant communication with identified individual at jobsite to maintain delivery schedule consistent with placement - never stack trucks at jobsite

Adjust truck schedules to manage delays

Communicate with responsible contractor party on discharge and set characteristics and adjust hydration stabilizer as necessary

Test Panel Identify test panel placement date and location Include company representative at test panel placement

Obtain written approval for mixture appearance

Ensure that percolation of placed test panel is verified

Obtain copy of results of fresh concrete density and other tests from test panel placement


Additional Tips for Drivers:Product Consistency Start with empty truck every load

Dump all wash water before loading Never batch on top of leftover concrete (standard or pervious) Failure to remove all contents CAN cause flash set, poor finish, low strengths Ensure that hot water is not used and side tanks store cold water

Loading, Mixing and Reading the Load

If possible, avoid using truck mixers that have difficulty with low slump concrete Notify dispatch if truck mixer used is having difficulty discharging pervious concrete Inspect blade condition, do not use trucks with build up Avoid truck with known mechanical problems that may delay unloading Mix at least 60-75 revolutions (8 Minutes) at 70% charging speed (minimum) at wash rack Pervious concrete does not sound like regular concrete Slump meters do not apply for pervious concrete Never add water unless instructed to Report dry or wet loads to batch operator before leaving plant and from jobsite

Tips for Recognizing Correct Moisture Content

Shiny metallic sheen is used as an initial indicator of designed moisture content Surface paste should be shiny and coated aggregate particles should stick to hand when squeezed and released If mix has dull or matte finish - the load is too dry. Do not place unless adjusted with authorization Paste runs freely from the aggregate - it's too wet- do not pour If the bottom of the mix seals up coming out of the chute it is likely too wet

To the jobsite Ensure mixer is in agitation mode during transport to jobsite If mix contains hydration stabilizing admixture agitate at low speed during transport excessive mixing will wear out admixture faster

Paperwork Requirements

Verify mix code and quantity on delivery ticket Batch recorded quantities may be requested

Jobsite addition of water or admixtures

Only Authorized Personnel may add water at jobsite Ensure that request for water addition is made after mix is evaluated If instructed to add water, mix for a full three (3) minutes or 50 revolutions after each water addition Record all jobsite added water on delivery ticket Hose hopper and fins off quickly. Do not use excessive water

Prevent build up in drum

If possible check truck weight prior to loading each time you load pervious concrete Rinse and empty drum between every load Report any build up


If possible rotate trucks off the placement if buildup occurs or after the delivery of 3-4 trips pending placement conditions

KEEP CAREFUL EYE ON YOUR LOAD!

Keep track of total time on load. Inform contractor at 1 hour Certified installers with authority may add more water or stabilizers

Tips for unloading Position truck to unload downhill if possible Use minimum number of chutes to increase discharge rate

If delays at the jobsite, revolve drum at agitating speed. Do not sit idle for long and do not over mix Put drum in full discharge and use throttle to vary the rate of discharge Do not discharge continuously into previously deposited concrete Coordinate with contractors chute man to control discharge

Return to plant Unload any returned concrete or water in drum before loading next batch Water in the drum will result in a wet load Returned concrete in drum will set up and accelerate set of next load Do not reuse returned pervious


Considerations for Ready Mixed Concrete Producer(Short Form)

Aggregate Density (Unit weight), Void content, Relative Density (Sp. Gr.) Pervious Mixture

Density and calculated voids at design void content within tolerance

Sample panel pour scheduled, placed and approved by owner Loader Operator

Load from correct stockpile

Work stockpile to manage uniform moisture

Avoid contamination use clean bucket

Avoid intermingling rock from stockpiles at different moisture

Keep bucket raised to avoid stockpile base or standing water

Ensure clean and empty bins before loading into plant Batching Trucks should be empty and clean

Do not use hot water in plant and in truck tanks

Follow proper batching sequence to avoid cement balls

Ensure batcher capacity is adequate Dispatch Schedule trucks that handle low slump loads

Verify mixture consistency on first load before batching second

Verify truck scheduling communicate with jobsite do not stack trucks Drivers Ensure empty and clean truck before batching

Verify mix code and quantity mix recordation may be requested

Pervious mixture sounds different

Slump meters should not be used

Add water at jobsite only at request of the contractor

Mix for 3 minutes or 50 revs after adding water

Unload downhill if possible

Put drum in full discharge and use throttle to vary speed

Slow discharge when requested by contractor

Maintain agitation if delays at jobsite


Checklist for Pervious Concrete Installer(Detailed Form)

Goal: to install a durable, permeable and long lasting pervious concrete pavement that meets the owners needs

Checklist Responsibility Notes

Mix design Approved and test panel poured and approved Specifications & shop drawing

Jointing and pour schedule; drawings on site Forms clearly marked with joint placement

Site work Meets specifications for grade and drainage Insure base or rock layer materials are at suitable moisture content - adjust based on ambient temperatures in summer months

Dampen subgrade prior to placement

Subgrade/base soaked 2 to 18 hours before pour and again just before pour

Grade to be re-checked and ruts removed throughout the placement

Forms Meet specifications with riser strips (if applicable) cut and on site and ready before placement

Crew Size Sufficient to adequate to place pervious and on hand to handle all placing, finishing and curing operations

Scheduling First truck will be inspected and approved before loading other loads

Complicated placements like corners and hard to reach areas are placed separately using appropriate tools for proper compaction

Work with plant to get mixture right and on schedule

Lead person on crew to work with batch plant and approve water on first and subsequent loads

Communicate with batch plant on adjustments needed Placement Do not place pervious concrete that is out of specification or of

improper consistency. Stop and correct problem

Do not place pervious when freezing temperatures are anticipated at least 7 days after pour

Sub-grade watered 2 to 12 hours prior and just before pour

Pending method of placement and equipment, finishing operations should begin immediately upon discharge Edging, compaction and jointing to begin immediately after screeding


Checklist Responsibility Notes

Surface stabilizers (not water) available as needed during any delay or in dry/windy air

Check permeability often if appearance for drainability is questionable. Use a small shot glass size container to pour water on the pavement surface and ensure it passes through quickly Wait longer if the paste washes off

Curing Plastic sheeting should be applied within 20 minutes, or less, after placement. Hot windy and dry conditions require earlier initiation of curing

If delays in placing concrete, place plastic sheeting over equipment, cover placement in the event of any delay

Plastic sheeting should overlap pavement edges and be continuous

Plastic sheeting and anchors cut and laid out along the placement before starting

Evaluate weather conditions temperature, wind, humidity to schedule curing timing

Be prepared to suspend paving if weather conditions dictate Joints Joint plan (as approved by the engineer) physically marked on

forms

Install joints as soon as possible without causing raveling

Re-hydrate the pervious concrete when plastic sheet has been removed for joint cutting in hot weather or when removed to facilitate adjacent lane placements within the 7 day curing period- replace plastic in a timely manner

Use a straight edge when installing sawed joints

Jointing tools for wet cutting are clean and ready to go, apply a release agent prior to cutting each joint

Do not roll joints with dry equipment; avoid use of water to lubricate the joint roller

Edging must be done immediately after screeding

Edging must leave a completely closed well rounded and compact radius. Open aggregate will ravel


Checklist for Pervious Concrete Installer(Short Form)

Pervious Mixture

Mixture approved

Test panel poured and approved Specification and Shop drawings

Reviewed

Joint plan established joint layout marked on forms

Pour schedule established Site work Meets specifications for grade, compaction and drainage

Subgrade/Base soaked 2-18 hours before pour

Base wetted just prior to pour

Grade rechecked to remove ruts Forms Meet specification with riser strips (if applicable) cut and on site

Staging placements planned to avoid delays during pour Crew Adequate numbers and qualifications to handle all operations Scheduling Inspect first truck notify plant of acceptance

Complicated placements to be accomplished separately

Work with plant to get mixture right and on schedule

Lead person on crew to work with batch plant and approve water on first and subsequent loads

Placement Subgrade/base water prior to pour

Edging, compaction and jointing to begin immediately after screeding

Surface stabilizers (not water) available as needed Curing Plastic sheeting ready to be applied in 20 minutes or less

Plastic sheeting cut and anchors ready

Evaluate weather conditions temperature, wind, humidity to schedule curing timing

Joints Joint plan approved and physically marked on forms

If saw cut, scheduled for installation to prevent joint raveling

Jointing tools cleaned and ready to use tools to tighten joints after scouring

Edge tamping and edging ready to be performed after screeding

Edging to ensure tight closed radius


Jobsite Pre-Construction ChecklistSubmittals Qualifications of installer

Pervious Concrete Mixture

Test panel placement and approval

Shop drawing for joints marked, depth, timing, types

Concrete plant and drivers informed on pervious placement

Testing lab tests, test methods, test samples Site work Subgrade and base thickness, grade and compaction check drainage

Soak base 2 12 hours before and just prior to placement Weather Weather forecast

Temperature

Wind and humidity considered

Surface stabilizers available

Curing materials and anchors

Curing procedures and timing

Authority to cancel and reschedule based on temperature Pre-placement confirmation

Pervious concrete mix approved

Joints marked

Joint layout approved

Saw cut timing

Block out of drainage or other structures in pavement

NRMCA 900 Spring Street, Silver Spring, MD, 20910 1.888.846.7622 www.nrmca.org

nrmca pervious concrete construction checklist

Documents

concrete suppliers

core density

weeks prior results

project acceptance

project needs

suggested checklists

size mixture density

week prior tests