Optimizing the Durability and Functionality of PFC Surfaces

Don WatsonTest Track Sponsor MeetingMay 11, 2011

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Objective• Durability Issues–Raveling–Crack Resistance

• Functionality Issues–Permeability– Smoothness– Structural Value

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–Raveling–Crack Resistance

Durability Issues

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4

Raveling

Change in Texture with Traffic

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1.00

1.10

1.20

1.30

1.40

1.50

1.60

1.70

0.00 2.00 4.00 6.00 8.00 10.00

Text

ure

Dept

h (m

m)

ESALs (Million)

N1

N2

N13

S3

S4

S8

Crack Resistance

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PFC Surface Cracks (Tack Method)

• 2006 crack susceptible dense Superpave mix– Surface cracks after 1.9M ESALs (Rehab at 5.6M)

• 2009 PFC surface placed with conventional tack– Surface cracks after 2.2M (cracking/pumping at 8.2M)

• 2009 bonded PFC surface placed with spray paver– Surface cracks after 4.1M (looks good at 8.2M)

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OGFC Surface Cracks (Tack Method)

Conventional Tack

Bonded

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5/2/2011 Crack Maps (N2 / N1)

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–Permeability– Smoothness– Structural Value

Functionality Issues

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Permeability

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Same Mix Drains Better at 1¼”

N1 - ¾”Bonded

N2 - ¾”Tacked

S8 - 1¼”Tacked

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Smoothness

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Change in Smoothness with Traffic

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50.0

60.0

70.0

80.0

90.0

100.0

110.0

120.0

130.0

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00

IRI (

in/m

i)

ESALs (Millions)

N1

N2

N13

S3

S4

S8

Structural Value

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Structural Contribution of OGFC

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Similar Rutting Performance

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Similar Strain Response

50% RAP

Virgin Mixes

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Questions??

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