MODULE 3-3MODULE 3-3MODULE 3-3MODULE 3-3

Patching WithPatching WithBituminous Bituminous

MixturesMixtures

Patching WithPatching WithBituminous Bituminous

MixturesMixtures

Learning ObjectivesLearning Objectives

Describe the conditions that require Describe the conditions that require patching patching

Distinguish between hot-, cold-, and Distinguish between hot-, cold-, and proprietary mix patching materialproprietary mix patching material

Describe patching materials propertiesDescribe patching materials properties Describe procedures for throw and roll, Describe procedures for throw and roll,

semi-permanent, and automated semi-permanent, and automated patchingpatching

IntroductionIntroduction

Patching the existing pavement with Patching the existing pavement with bituminous materialsbituminous materials

Extends the service life of the existing Extends the service life of the existing HMAHMA

Used in the preparation of existing Used in the preparation of existing pavement prior to construction of an pavement prior to construction of an HMA overlayHMA overlay

Moderate Severity

High Severity

Patching ApplicationsPatching Applications

Definitions – Definitions – Bituminous Patching Bituminous Patching Materials Materials

Cold-mixCold-mix Often used as temporary patchesOften used as temporary patches Placed in stockpile and used over a Placed in stockpile and used over a

period of time (emulsion binders)period of time (emulsion binders) Special open-graded mixesSpecial open-graded mixes

Proprietary-mixProprietary-mix Cold mix with emulsified binderCold mix with emulsified binder Proprietary admixturesProprietary admixtures

Definitions – Definitions – Bituminous Patching Bituminous Patching Materials Materials

Hot-mix asphalt (HMA)Hot-mix asphalt (HMA)

Placed immediately while hotPlaced immediately while hot

Standard dense graded HMAStandard dense graded HMA

Why Do We Patch?Why Do We Patch?

Repair localized distressRepair localized distress

Improve motorist safetyImprove motorist safety

Reduce pavement roughnessReduce pavement roughness

Reduce the rate of deteriorationReduce the rate of deterioration

Repair pavement prior to overlayRepair pavement prior to overlay

Desirable Mix Desirable Mix Properties Properties Bituminous Patching Bituminous Patching

StabilityStability

AdhesivenessAdhesiveness

Resistance to strippingResistance to stripping

DurabilityDurability

Workability (cold-mix)Workability (cold-mix)

Storability (cold-mix)Storability (cold-mix)

Limitations and Limitations and EffectivenessEffectiveness

Patching may not be appropriate for all Patching may not be appropriate for all applicationsapplications

Temporary patches are temporaryTemporary patches are temporary

Structural design may not be Structural design may not be adequateadequate

Principal problem may not be Principal problem may not be correctedcorrected

Limitations and Limitations and EffectivenessEffectiveness

Bituminous patching is not Bituminous patching is not recommended for permanent repair of recommended for permanent repair of rigid pavementsrigid pavements

Hot-mix, full-depth patches provide Hot-mix, full-depth patches provide maximum effectivenessmaximum effectiveness

Not cost-effective when pavement is Not cost-effective when pavement is extensively deterioratedextensively deteriorated

0

10

20

30

40

50

60

70

80

Station50 100 1500

Def

lect

ion

Cracking

Pavement Repair

Pavement Survey Pavement Survey and Markingand Marking

PerformancePerformance

Winter maintenanceWinter maintenance ““Throw and Roll” the most cost effectiveThrow and Roll” the most cost effective Spray injection device also very Spray injection device also very

efficientefficient Summer maintenanceSummer maintenance

Semi-permanent patch Semi-permanent patch Pennsylvania found to be 3X more cost Pennsylvania found to be 3X more cost

effective on LCCA basiseffective on LCCA basis

Poor ConditionsPoor Conditions

Throw and RollThrow and Roll

Fill the hole with patching materialFill the hole with patching material Compact the patch using truck tiresCompact the patch using truck tires Verify that the compacted patch has Verify that the compacted patch has

some crown (between 3 and 6 mm).some crown (between 3 and 6 mm). Move on to the next pothole.Move on to the next pothole. Open the repaired section to traffic as Open the repaired section to traffic as

soon as maintenance workers and soon as maintenance workers and equipment are cleared from the area.equipment are cleared from the area.

Semi-Permanent Semi-Permanent PatchPatch

Mark patch boundariesMark patch boundaries Cut boundariesCut boundaries Clean and repair foundationClean and repair foundation Apply tack coatApply tack coat Fill the hole with patching materialFill the hole with patching material Compact the patchCompact the patch CleanupCleanup

Automated Patching Automated Patching EquipmentEquipment

Spray injection proceduresSpray injection procedures

Blow debris from holeBlow debris from hole

Spray hole with binder for tack coatSpray hole with binder for tack coat

Blow aggregate and binder into holeBlow aggregate and binder into hole

Top off with a layer of uncoated Top off with a layer of uncoated aggregate to prevent trackingaggregate to prevent tracking

May be rolled to improve smoothnessMay be rolled to improve smoothness

Automated Patching Automated Patching EquipmentEquipment

Automated Patching Automated Patching EquipmentEquipment

What’s Wrong Here?What’s Wrong Here?

What’s Wrong Here?What’s Wrong Here?

ReviewReview

What are the properties to look for in a What are the properties to look for in a patching material?patching material?

What are the major differences between What are the major differences between hot-, cold-, and proprietary mix hot-, cold-, and proprietary mix patching material?patching material?

Why do we patch?Why do we patch? What are appropriate applications of What are appropriate applications of

“throw and roll,” “semi-permanent,” and “throw and roll,” “semi-permanent,” and “automated” patching?“automated” patching?

Key ReferencesKey References

Wilson, T. P. 1998. Wilson, T. P. 1998. Long-Term Monitoring of Long-Term Monitoring of Pavement Maintenance Materials Test SitesPavement Maintenance Materials Test Sites. . FHWA-RD-98-073. Federal Highway FHWA-RD-98-073. Federal Highway Administration, Washington, DC.Administration, Washington, DC.

Wilson, T. P. and A. R. Romine. 1999. Wilson, T. P. and A. R. Romine. 1999. Materials and Procedures for the Repair of Materials and Procedures for the Repair of Potholes in Asphalt-Surfaced Pavements--Potholes in Asphalt-Surfaced Pavements--Manual of Practice.Manual of Practice. FHWA-RD-99-168. FHWA-RD-99-168. Federal Highway Administration, Washington, Federal Highway Administration, Washington, DC.DC.