NRMCA Pervious Concrete Construction Checklist
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Transcript of NRMCA Pervious Concrete Construction Checklist
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NRMCAPERVIOUS CONCRETECONSTRUCTONCHECKLISTS
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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.
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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
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Appendix A: Checklists
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
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NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE
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
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Appendix A: Checklists
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
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NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE
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.
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Appendix A: Checklists
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
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NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE
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
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Appendix A: Checklists
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
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NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE
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
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Appendix A: Checklists
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
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NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE
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
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Appendix A: Checklists
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
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NRMCA PERVIOUS CONCRETE CONTRACTOR CERTIFICATION TEXT REFERENCE
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
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Appendix A: Checklists
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
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NRMCA 900 Spring Street, Silver Spring, MD, 20910 1.888.846.7622 www.nrmca.org