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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