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Surface Rehabilitation Treatments

Ohio Local Technical Assistance Program (LTAP)1980 W Broad St., Columbus, OH 43223614-387-7359 or Toll Free 877-800-0031

Introduction• Surface rehabilitation techniques

Low-volume roads – most historical useHigh-volume roads - improved materials and processesPavement preservation application

Definitions• Fog seal• Sand seal• Scrub seal• Chip seal• Slurry seal• Microsurfacing• Cape seal• Sandwich seal

• Distress Resistant Membrane DRMTM

Interlayer or Surface

• Thin OverlaysSmoothseal

• Nova Chip®

Fog Seal

Fog Seal• Seal pavement

surface• Rejuvenate oxidized

HMA• Provide delineation

Sand Seal• Seal pavement surface• Rejuvenate oxidized HMA• Provide delineation• Improve friction

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Scrub Seal Scrub Seal• Surface restoration that rejuvenates

asphalt and fills voids and cracks• Application process

Apply polymer-modified asphalt agentBroom asphalt into voids and cracksApply sand or small aggregateBroom aggregate and asphalt mixtureRoll with pneumatic tire roller

Asphalt Chip Seal Asphalt Chip Seal

Asphalt Chip Seal• Provide wearing course• Improve surface friction• Rubberized

Bridge and seal cracksDelay reflective cracking

Slurry Seal• Seal

pavement surface

• Retard surface raveling

• Improved surface friction

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• Level pavement surface• Fill ruts• Restore surface

friction

Microsurfacing Cape SealCombination:

Chip SealSlurry Seal Thicker & Smoother

• Seal pavement surface• Improve surface friction

Sandwich Seal• Three layers

Large aggregate on bottomAsphalt Layer (single)Smaller aggregate

• Seal pavement surface• Improve surface friction

Distress Resistant Membrane Interlayer

Distress Resistant Membrane

Distress Resistant Membrane Surface

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Fiber Mat SAMI Fiber Mat SAMI

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Nova Chip®• Gap graded HMA• Heavy tack coat applied first (0.7-1.0 l/m2)• Proprietary machine and process• Paver applies both tack coat and HMA• Functional, not a structural overlay

Nova Chip®

ODOT Supplemental Specification 424 Polymer

Modified Asphalt Concrete, Type A & B

Smoothseal

Smoothseal• ODOT 424, Fine Graded Polymer Modified Asphalt

Concrete, ( Smoothseal)

• Formulated specifically for the PM, thin overlay application, placed 3/4 to 1 inch thick,

• Type A for medium traffic and urban applications

• Type B, “Smoothseal” for any and all applications including heavy traffic

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424 Polymer Modified Asphalt Concrete, Type A

• Based on old spec SS-854 Rubberized Sand Asphalt • Light & Medium Traffic• Blend of asphalt and mason sands• Skid Resistant

natural sand with min 50% silicon dioxide• 8.5 % PG76-22M or PG64-22 SBR modified binder• 5.0% SBS or SBR polymer by weight of binder (vs.

3.5%) • Recipe mix design

− Similar to old proposal note 715 rubberized sand asphalt −Marshall designed mix for light, medium or heavy traffic− Blend of 3/8 max size aggregate and sand size particles

Min VMA 15%Min Binder 6.5%Design Air Voids 4.0%

−Crushed aggregatesMedium traffic 10 % Two fractured facesHeavy traffic 100% Two fractured faces

− Skid Resistant - natural sand with min 50% silicon dioxide− 8.5 % PG76-22M or PG64-22 SBR modified binder− 5.0% SBS or SBR polymer by weight of binder

424 Polymer Modified Asphalt Concrete, Type B

Purpose and Application• Provide a new wearing surface• Seal cracks in the surface• Waterproof the surface• Improve pavement surface friction and

surface drainage

Why apply a surface treatment?

Purpose and Application• Slow pavement weathering and aging• Improve the surface appearance• Provide visual delineation between the

mainline pavement and the shoulder

Matching Condition to Treatment

• Performance of surface treatments highly dependent upon existing surface condition

• Pavement Condition

• Traffic Level

• Climate

Pavement Surveys• Type of distress

Surface treatment type• More severe cracking

“Heavier” surface treatment• Distorted pavement surface

“Leveling” treatment

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Applicable Pavement Conditions

• OxidationFog sealScrub sealSand sealSlurry sealDRMTM

• BleedingSandwich sealsMicrosurfacing

• FrictionSlurry sealAsphalt chip sealMicrosurfacingDRMTM

Nova Chip®

Applicable Pavement Conditions

• CrackingScrub sealSlurry sealAsphalt chip sealCape sealDRMTM

Fiber MatNova Chip®

• RuttingMicrosurfacingNova Chip®

Design and Construction Considerations Fog Seals

• Light coating of asphalt cement applied usually as an emulsion

• Traffic allowed on in 2-4 hours after water has evaporated

• Surface may be slick if traffic allowed too soon

Design ConsiderationsAsphalt Chip Seals

• Existing pavement condition• Asphalt type• Aggregate• Quantity selections• Local conditions and experience• General environment• Traffic volume and handling• Contractor experience and availability

Thin Overlays

• Similar to HMA• Limited time for compaction due to

thin lift (≤25 mm)seasonal restrictions on placementAir/pavement temperature critical

• No Vibratory/Pneumatic (rubber tired) compaction equipment

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Urban vs. RuralTraffic Control

Urban vs. RuralTraffic Control

Urban vs. RuralNighttime Work

Urban vs. RuralUtilities & Appurtenances

Urban vs. RuralUtilities & Appurtenances Surface Rehabilitation

Treatments

• Questions?