Home owners and Commercial Pavement Preservation

What is Pavement Preservation?

When you build a pavement it starts to deteriorate from aging traffic and water
If you wait till it has potholes or extensive cracking it is really too late and rehabilitation is required
If you apply treatments before it happens it can last longer and will cost less!

Preservation: Maintenance

Stopping problems before they grow
Maximizing the life of the pavement structure by PROTECTING it.
Regular applications of preservation methods

General Requirements

Timely
Affordable
Cost Effective
Technically Effective

Rehabilitation

Repairing problems without reconstruction
Follow up with preservation treatments

Failures

Structural - Underlying Pavement
Bonding
Surface

Structural Failures
	Poor Design Underestimation of traffic Poor Drainage Overloading Poor Materials Poor Construction Practice Failing to take the local climate into account!

Bonding Failure
	Slippage between layers Poor construction practice or conditions Contamination Traffic type, frequency and situation Climate, especially wet

Surface Failure
Pavement underlying Aging Poor Design Poor Materials Traffic Wrong Method

Main Distress Modes
Deformation Cracking Disintegration

Main Mechanisms

Aging
Water Damage
Traffic
Climate

Main results

Cracks
Potholes
Skid resistance loss
Profile loss
Water ponding

Failure Assessment

Differentiate Where The Failures have Occurred
Determine Serviceability
Determine Appropriate and Economic Treatment

Types of Preservation Methods

Crack Sealing – waterproofing pavement
Patching- water proofing improving ride
Seal Coating- cosmetic surfacing
Slurry Seal- sealing
Microsurfacing- sealing
Chip Seal- sealing
Cape Seal- sealing surface profile
HMA overlays- sealing surface profile

Types Of Rehabilitation

Microsurfacing Rut Filling
Stabilization-Recycle
Asphalt Rubber Overlays
Asphalt Rubber Chip Seals
Cape Seals

CRACK SEALING

What is Crack Sealing?

Cracks are filled with a rubberized hot or cold filler
This is applied using a heated pot or other injection device
Cracks are slightly overfilled to allow for shrinkage
A layer of dust non stick additive or unwashed sand is placed on top to prevent pick up

What Does it Do?

It fills cracks creating a water proofing
Correct product will expand and contract with the crack to maintain sealing in all seasons and under traffic
Crack sealing is a pretreatment before a surface coat or may be used alone

Method

When is it Used?

Cracks should be low activity like age cracks
Fatigue cracks require asphalt rubber membranes before subsequent surfacing
Extensively cracked roads require membrane treatment
It should be done when cracks are at their widest
It may be done the year before surfacing
Hot pour crack fillers are better than cold pour

Crack Sealing

Cost?: How Long Will it Last?

This depends on the materials used
The area to be filled
The equipment to be used
Crack filling is often the least expensive option
Crack filling and proper surfacing will last the life of the pavement.
Crack filling alone will last 3-5 years, however other cracks will open up in 6 mths to 1 year.

PATCHING

Injection Patching

Hot Or Cold Mix Patching

What is it?

Areas of failed pavement are dug out and filled with hot mix or cold mixed asphalt. A tack coat of emulsion is applied first.
Potholes that are isolated are filled with a mix of asphalt emulsion and aggregates- injection patching.This is applied using a special machine
Holes are slightly overfilled to allow for compaction by roller and traffic
A layer of dust non stick additive or unwashed sand is placed on top to prevent pick up

What Does it do?

Failed pavement may be replaced
Holes are filled and the pavement waterproofing restored
Pavement smoothness is improved

Method - Mix Filling

Hole
Cut square, straighten edges
Tack coat
Fill hole
Compact
Traffic

Method - Injection Patching
Blow out Hole Tack Fill with emulsion aggregate mix Apply thin layer of dry aggregate Traffic

Mix Patching: When is it Used?

For deep patches especially where dig outs have occurred in fatigues pavement
Strengthening and full depth patches
Repair before surfacing

Injection Patching: When is it Used?

Rural roads
Parking lots
Shallow patches where water damage is not extensive
Repair before surfacing

Cost?: How Long Does it Last?

Injection patching is inexpensive and large areas can be done in a day
Hot mix patching is the most expansive patching method
Properly patched and surfaced pavements should last as long as the pavement is designed for.
Injection patching alone will last 2-3 years
Hot mix patching alone will last 5-8 years.

SEAL COATING

What Is It?

A thin application of a mixture of very fine aggregates, fillers and additives mixed with a slow setting asphalt emulsion (coal tar emulsion in some places)
May be applied by hand or by machine

What Does it Do?

Makes a smooth surface for parking lots or footpaths
Coats and protects the pavement
Creates a uniform and attractive black finish
Is not a high speed surface, adds no structural value. It will re-crack.

Method

When Is It Used?

Parking Lots
Driveways
Private slow speed roads
Play areas

Cost?: How Long Does it Last?

Inexpensive cover technique
Cheap but not long lasting
Pavement must be sound
Cosmetic use mainly
On a sound pavement seal coat will last 2-3 years.

SLURRY SEAL

What is it?

Slurry is a mixture of graded aggregates, asphalt emulsion, additives and often polymers
It is applied using a special paver mounted on a truck or self propelled
Components are metered into a pugmill, mixed and spread on the surface at 1- 1.5 top size stone thick
Slurry is a hard wearing road surfacing

What Does It Do?

Seals minor cracks
Seals sound but oxidized pavements
Restores surface texture and skid resistance
Corrects raveling
Reduces noise
Allows overlays where weight restrictions apply
Improves ride and profile

Application

Method

What Does It Cost?

How Long Does It Last?

USA figures indicate 5-8 years for slurry. Internationally figures of 5-10 years are quoted.
Jobs on highly trafficked roads are documented up to 15 years on sound pavements.
Must be used on sound pavements or else another treatment is required like an asphalt rubber seal before the slurry is applied.

CHIP SEAL

What Is It?

Chip Seals are an application of a binder followed by spreading of an aggregate (single size preferred).
It may be applied in multiple layers
It may be applied with a modified asphalt as a crack treatment alone or before a hot mix overlay

What Does It Do?

Waterproofs pavement
Protects underlying surface from aging
Restores friction
Eliminates dust
May be a crack treatment
Provides a hard wearing surface

Method

Asphalt Rubber Chip Seal after 5 years

What Does It Cost?: How Long Does it Last?

Chip Seals cost depends on the materials and applications used.
Chip Seal with emulsion is more expensive than slurry seals but hot chip seals-unmodified are less expensive than slurry seals
Chip Seals last 5-8 years depending on the surface they are put on and the binder used.

CAPE SEALS