Construction of Pervious Concrete Pavements
From the Pervious Concrete Certification Program
SITE PREPARATION
Duraport Parking Lot, Bayonne, NJPlaced October 2007
Site Preparation – Cut and Fill
Site can be graded flat to maximize storage of stormwater
Recharge Bed Preparation
Place and compact stone to desired depth
Keep stone cleanRemove all dirt and debris that may clog recharge bed
Site Preparation - Compaction
Compact subgrade to 92% of modified proctorCompact aggregate base to 95% of modified proctor
Don’t over compact, subgrade must remain permeable
Filter Fabric
Non-woven geotextile fabric is specified toprevent migration of fines into recharge bed
Setting Forms
Use string lines to set form elevation
Wood or steel forms can be used
Crew Duties – 8 Man Crew + 1
1 handles chute & hose
3 rake and level
2 strike-off/compact (run screed)
2 finish (side roller), joint, edge and cure (plastic)
1 to oversee all
Finishing: The Typical Process
SpreadingStrike-offCompactingJointing/EdgingCuring
1
2
3
4
5
Spreading 1
Moistened Base 1
Proper Water Content
When concrete arrives on site, check for quality
“Squeeze test”grab a handful, squeeze for 5 seconds, releaseHalf of your hand should be coated with paste
1
How Do You Know Its Right? 1
Look for ‘wet metallic sheen’
Recharge Bed Preparation
Rake out tire tracks
Mixer Discharge 1
Hang no chutes
Use only one chute section
Pervious Concrete Placement 1
Edges
Tamp the edges (approx 3’-6”) for durability
1
Edges
Place the edges first, then work toward the middle
1
Edges
Place the edges in lifts, tamp, and continue to top of form
1
Strike-off 2
Pervious Concrete Finishing
Smooth and compactpervious concrete ½”+/- to desired final grade
Hydraulic roller steelscreed recommended –10 psi down pressure recommended
2
Pervious Concrete Finishing 2
Small Jobs - Sidewalks 2
Compacting 3
Delaying compaction may cause raveling on a pervious concrete pavementCompaction takes place in top ½ inch of surfaceCompaction sets aggregate and smoothes the surface
3Compaction
Compacting the Edges 3
Cross Rolling 3
Edges
Use an edging tool to round-off edgesTamp tool – do not slide tool
3
Surface Texture
Important to keep the voids openDo NOT use trowelsDo NOT seal the surfaceNo roller marks
3
Jointing 4
Joints 4
Joints
Cut joints with a special “jointing” tool with a radiusmachined at the flange
Joints should be cut at least ¼ the thicknessof the slab
4
Jointing Technique 4
Curing 5
Curing
• Cure with 6 mil plastic for at least 7 days
• Cover within 20 minutes
5
Properly Secured Curing 5
Hold plastic down by nailing to forms or placing wood or rebar over plastic – do not use dirt
Thank You
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