MODULE 3-2MODULE 3-2MODULE 3-2MODULE 3-2

Crack SealingCrack SealingCrack SealingCrack Sealing

Learning ObjectivesLearning Objectives

Describe the primary sealant typesDescribe the primary sealant types

Describe the major factors that affect Describe the major factors that affect performanceperformance

Describe conditions best-suited for Describe conditions best-suited for crack sealingcrack sealing

Describe procedures for crack Describe procedures for crack sealing/resealing in HMA pavementssealing/resealing in HMA pavements

List safety considerationsList safety considerations

IntroductionIntroduction

Crack sealing is applied toCrack sealing is applied to

Preserves the intended design lifePreserves the intended design life

Extend the service life of the existing Extend the service life of the existing HMA by reducing moisture infiltrationHMA by reducing moisture infiltration

Prepare the existing pavement prior Prepare the existing pavement prior to construction of an HMA overlayto construction of an HMA overlay

Do you seal or not, Do you seal or not, what is your what is your practice?practice?

Sealant TypesSealant Types

Thermoplastic sealant materials – Thermoplastic sealant materials – common for HMA applicationcommon for HMA application

Thermosetting sealant materials – not Thermosetting sealant materials – not commonly applied for HMA pavementscommonly applied for HMA pavements

See Table 3-2.1See Table 3-2.1

Thermoplastic Thermoplastic Sealant MaterialsSealant Materials

Bitumen-based materials (e.g., ASTM D Bitumen-based materials (e.g., ASTM D 3381, D 3405, D 1190, D 244)3381, D 3405, D 1190, D 244)

Typically soften upon heating and Typically soften upon heating and harden upon coolingharden upon cooling

Hot AppliedHot Applied

Cold AppliedCold Applied

Material cost: $0.10 – 2.00 per kgMaterial cost: $0.10 – 2.00 per kg

Installed cost: $1.00/mInstalled cost: $1.00/m

Thermosetting Thermosetting Sealant MaterialsSealant Materials

One or two-component materials One or two-component materials

Set obtained bySet obtained by

Chemically curedChemically cured

Solvent releaseSolvent release

Material costs: $2.00 – 8.00 per kgMaterial costs: $2.00 – 8.00 per kg

Installed costs: $2.00 – 5.00/mInstalled costs: $2.00 – 5.00/m

Purpose and Purpose and ApplicationApplication

Reduce moisture infiltrationReduce moisture infiltration

Stripping, cupping, delaminationStripping, cupping, delamination

Reduce incompressibles filling cracksReduce incompressibles filling cracks

Application - HMA pavementApplication - HMA pavement

Limitations and Limitations and EffectivenessEffectiveness

Continuing debate regarding the cost Continuing debate regarding the cost effectiveness of crack sealingeffectiveness of crack sealing

SHRP experiments SPS-3 examined SHRP experiments SPS-3 examined the effect of sealing activities on the effect of sealing activities on pavement performancepavement performance

Crack sealing performed well except Crack sealing performed well except in dry regions of U.S.in dry regions of U.S.

Limitations and Limitations and EffectivenessEffectiveness

General consensus among states that General consensus among states that supports sealing cracks as a cost supports sealing cracks as a cost effective rehabilitation or maintenance effective rehabilitation or maintenance treatmenttreatment

66% of States seal cracks in HMA 66% of States seal cracks in HMA pavementspavements

Is Crack Sealing Is Crack Sealing Effective Here?Effective Here?

Do you seal by policy or by effectiveness?Do you seal by policy or by effectiveness? What sealant is most effective for your What sealant is most effective for your

climate, materials, and traffic?climate, materials, and traffic? How do you pick candidate projects?How do you pick candidate projects?

OverlayOverlay Preventive MaintenancePreventive Maintenance

What effect on pavement life?What effect on pavement life?

Design Design ConsiderationsConsiderations

Climate conditionsClimate conditions Highway classificationHighway classification Traffic level and % trucksTraffic level and % trucks Pavement condition and planned Pavement condition and planned

rehabilitationrehabilitation Crack characteristicsCrack characteristics Materials and placement configurationMaterials and placement configuration Procedures, equipment, and safetyProcedures, equipment, and safety

Would You Seal This?Would You Seal This?

Would You Seal This?Would You Seal This?

Design Design ConsiderationsConsiderations

Two different procedures are now Two different procedures are now defined (SHRP-H-348)defined (SHRP-H-348)

Crack sealing: working cracks with Crack sealing: working cracks with movement movement ≥ 2.5 mm (0.1 in)≥ 2.5 mm (0.1 in)

Crack filling: non-working cracksCrack filling: non-working cracks

Factors Affecting Factors Affecting PerformancePerformance

Candidate pavementCandidate pavement

SealantSealant

ConfigurationConfiguration

PreparationPreparation

ApplicationApplication

Quality controlQuality control

Ideal Application Ideal Application ConditionsConditions

New or recently rehabilitated surfaceNew or recently rehabilitated surface

Good base supportGood base support

Little or no secondary crackingLittle or no secondary cracking

Little or no raveling at crack faceLittle or no raveling at crack face

Cool weather (fall or spring)Cool weather (fall or spring)

Proper preparation (clean and dry)Proper preparation (clean and dry)

Placement Placement ConfigurationsConfigurations

Reservoir

Material

Crack

Standard Reservoir And Flush

Material

Crack

Simple Flush Fill

Placement Placement ConfigurationsConfigurations

Standard Reservoir And Recess

Material

Crack

Recess

Reservoir

Material

Crack

Cap

Capped

Placement Placement ConfigurationsConfigurations

Material

Crack

Deep Reservoir-and-Recess

Reservoir

Material

Crack

Band-Aid

Shallow Recessed Band-Aid

BackerRod

Placement Placement ConfigurationsConfigurations

Material

Crack

Band-Aid

Simple Band-Aid

Reservoir

Material

Crack

Band-Aid

Standard Recessed Band-Aid

Cost ConsiderationsCost Considerations

Amount of crack to be filled, sealedAmount of crack to be filled, sealed Type of crack filler, sealerType of crack filler, sealer

Material costs: $0.10 to $8.00 per kgMaterial costs: $0.10 to $8.00 per kg Equipment and personnel requiredEquipment and personnel required Estimated performance of crack fill or sealEstimated performance of crack fill or seal Method of payment – lf of cracksMethod of payment – lf of cracks or pounds of or pounds of

sealantsealant Installed cost: $1.00 to $5.00+/mInstalled cost: $1.00 to $5.00+/m

Construction Construction SequenceSequence

Crack sealingCrack sealing

Crack fillingCrack filling

Crack SealingCrack Sealing

Crack refacingCrack refacing

Crack cleaningCrack cleaning

Sealant installationSealant installation

Vertical Spindle Vertical Spindle RouterRouter

Rotary Impact RouterRotary Impact Router

AirblastingAirblasting

Hot Compressed Air Hot Compressed Air LanceLance

Hot Compressed Air Hot Compressed Air LanceLance

Excessive Hot Air Excessive Hot Air LanceLance

Squeegeed SealantSqueegeed Sealant

Finished Crack SealFinished Crack Seal

Crack FillingCrack Filling

Crack cleaningCrack cleaning

Sealant InstallationSealant Installation

SafetySafety

TrafficTraffic Hot MaterialsHot Materials NoiseNoise Flying debrisFlying debris Air qualityAir quality Pavement Pavement

frictionfriction

ReviewReview

What are the primary sealant types?What are the primary sealant types? What are the major factors that affect What are the major factors that affect

performance?performance? What are the conditions necessary for best What are the conditions necessary for best

performance of the pavement and crack performance of the pavement and crack sealant?sealant?

What are the major steps in the crack What are the major steps in the crack sealing/resealing for HMA pavements?sealing/resealing for HMA pavements?

List three safety considerations in the crack List three safety considerations in the crack sealing operation?sealing operation?

Key ReferencesKey References

Hand, A. J., et. al. 2000. “Cost-Effectiveness Hand, A. J., et. al. 2000. “Cost-Effectiveness of Joint and Crack Sealing: Synthesis of of Joint and Crack Sealing: Synthesis of Practice.” Practice.” Journal of Transportation Journal of Transportation Engineering.Engineering. November/December 2000. November/December 2000. Volume 126, Number 6. American Society of Volume 126, Number 6. American Society of Civil Engineers, Reston, VA.Civil Engineers, Reston, VA.

Smith, K. L. and A. R. Romine. 1999. Smith, K. L. and A. R. Romine. 1999. LTPP LTPP Pavement Maintenance Materials: SHRP Pavement Maintenance Materials: SHRP Crack Treatment Experiment, Final Report.Crack Treatment Experiment, Final Report. FHWA-RD-99-143. Federal Highway FHWA-RD-99-143. Federal Highway Administration, Washington, DC.Administration, Washington, DC.

Key ReferencesKey References

Smith, K. L., and A. R. Romine. 1999. Smith, K. L., and A. R. Romine. 1999. Materials and Procedures for Sealing and Materials and Procedures for Sealing and Filling Cracks in Asphalt-Surfaced Pavements Filling Cracks in Asphalt-Surfaced Pavements – Manual of Practice– Manual of Practice. FHWA-RD-99-147. . FHWA-RD-99-147. Federal Highway Administration, Washington, Federal Highway Administration, Washington, DC.DC.