PAVEMENT MAINTENANCE 1Part 3: Potholes and Cracks

Idaho Roads Scholar Program

Objectives Explore alternatives for repairing

potholes, Review options for extensive patching, Investigate methods and materials for

treating pavement cracking.

HOW A POTHOLE DEVELOPS

HOW A POTHOLEDEVELOPS

Elements of Successful Pothole Patching

Use high-quality patching materials, which are cost-effective compared to less expensive products.

Place--do not throw--material in the patch area.

Compact every patch.

High Quality Cold Mixes Include:

Carefully selected aggregate types and gradations Very clean, durable aggregates Very little sand-mixtures are

porous Polymer modified binder Additives that promote adhesion in

wet conditions

Asphalt Cold Patch Materials

Standard Spec 00745.00 Asphalt Cold Patch-High Performance

Qualified Products List available describing suitable materials

““There’s a gentleman here to see you about potholes.”There’s a gentleman here to see you about potholes.”

Permanent Repairs

Dig Out and Repair

Identify area affected Remove to sound material Clean, tack edges Place patching mixture Compact Check level

Mark Area to be Patched

Mark patch area, extending at least 1 foot outside of distressed area.

Remove Failed Materials

Place Patching Mixture

Spread Mixture Carefully

Compact Each Lift Thoroughly

Straight-edge the Patch

Blown-in Pothole Filler

Blown-In Filler

SPRAY INJECTION

The hole is cleaned with a high volume blower.

A tack coat of asphalt is applied to the area.

A mixture of aggregate and hot asphalt fills the hole.

A finish coat of aggregate, and traffic flows.

Patching Rules of Thumb

Dig out 1 foot beyond the visible cracking

Don’t rock the jackhammer Dig out at least 1 1/2 times the

thickness of the failed AC Compaction, compaction,

compaction.

Questions?

Potholes

and Cracks

Crack TreatmentsPurpose

Used to prevent water and debris from entering individual cracks in the asphalt pavement surface

Crack treatments are both a corrective and preventative maintenance treatment.

Crack Sealing

Distress TypeFatigue Cracking

Linear & Block Cracking“Stable” Rutting

RavelingFlushing/Bleeding

RoughnessFriction Loss

Moisture DamageShoving

Extent of ProblemMinor Major

FeasibleNot Appropriate

FeasibilityFeasibility

Crack Sealing

Distress Type

Fatigue CrackingLinear & Block Crack

“Stable” RuttingRaveling

Flushing/BleedingRoughness

Friction LossMoisture Damage

Shoving

Extent of ProblemMinor Major

EffectiveMarginal

No Impact

Effectiveness

Crack Repair Guidelines

Filling (sand or sand-emulsion slurry)

Patching (cut and replace material)

> 3 /4 inch (19 mm)

Crack Fill (short life, prep for resurfacing)

Crack Seal (> 5 yr life)

1/8 – 3/4 inch(3 – 19 mm)

Do nothing Fog seal

Surface treatment (chip seal, slurry, etc.)

< 1/8 inch (3 mm), non-working

Treatment OptionsCrack Width

Don’t do this!

Or this!

Proper Crack Sealing Technique

For Effective Crack Sealing:

Perform sealing during late fall/early spring when cracks are open.

Sealing does not proceed if rain is imminent. Ambient or surface temperature should meet

manufacturer’s requirements—usually 40F and rising for routing and sealing.

Use appropriate materials.

Preparation is Key!

Spray the weeds in advance Clean the pavement surface. Provide for traffic control. Clean the crack, removing any

moss or grass out of crack. Dry the crack if necessary. (Hot air

lance) Fill it with crack seal material. Apply something to surface of seal

to minimize the tackiness.

Pavement Preparation Cleaning and Drying

Broom Compressed Air Sandblasting Hot Air Blasting (Heat Lance)

Cracks Must Be Clean & DryCracks Must Be Clean & DryUse Compressed AirUse Compressed Air

Note: Be Sure Compressor Is Equipped With A Note: Be Sure Compressor Is Equipped With A Moisture TrapMoisture Trap

...Or Clean with a Hot Air Lance

Up to 3000°F

> 2000 ft/sec blast velocity

Propane burner-no flame

Conducted immediately ahead

of sealant installation (5 mins or

50 yards max)

Comments: For wet conditions, lance can improve performance Otherwise, compressed air may be more effective (Québec

study)

Rout and Seal

Cut the pavement to a prescribed width and depth

Improves sealant performance Better adhesion Reduced tensile

stress on material

Crafco, Inc

W

D

W = 0.5” to 0.75”W = 0.5” to 0.75”D = 0.5” to 0.75”D = 0.5” to 0.75”

Typical Dimensions:Typical Dimensions:

Crack SealingCrack Sealing

Traffic Control

Detour traffic until seal cures Cover sealant with sand for quick

opening Begin filling at pavement centerline

Blotting Materials

Dry sand Toilet paper (proven effective

in SHRP research!)

Crack Seal Materials

Standard Spec 00746.00 Poured Filler/ Hot Poured

Qualified Products List available describing suitable materials

Crack Seal

The most common product used: D1190 Cost per pound: $0.26 Cost per linear foot to crack seal: $0.40 Should reseal after 5 years?

Crack Sealing

Crack Sealing Rules of Thumb

For linear cracks only (not intended form alligator cracking)

Clean cracks with forced air or heat lance

Don’t over-fill crack with sealant; avoid surface smears

Sweep up excess sanding

Review Investigate methods and materials for

treating pavement cracking, Explore alternatives for repairing

potholes, Review options for extensive patching.

Questions?

Potholes

and Cracks

Small Group Activity

Identify the distress Describe the cause Outline the optimum maintenance

repair

10 Minutes

Photo No. 1:Photo No. 1:

Photo No. 2:Photo No. 2:

Photo No. 3:Photo No. 3:

AI 38: Use AI 38: Use for Group Group

Photo No. 4:Photo No. 4:

AI 30: Use AI 30: Use for Group Group

Photo No. 5:Photo No. 5:

AI 47: Use AI 47: Use for Group Group

Photo No. 6:Photo No. 6:

AI 47: Use AI 47: Use for Group Group

Photo No. 7:Photo No. 7: