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Pavement Preservation • Definitions • Benefits of Preventive Maintenance • Asset Management • Agency & Industry Challenges • Preventive Maintenance Treatments • Conclusions
Pavement Preservation
• Definitions
• Benefits of Preventive Maintenance
• Asset Management
• Agency & Industry Challenges
• Preventive Maintenance Treatments
• Conclusions
Pavement Preservation
The sum of all activities undertaken to provide
and maintain serviceable roadways; this
includes corrective or routine maintenance and
preventive maintenance as well as minor
rehabilitation work.
Routine Maintenance
• Reactive in nature
• Fixing a defect once it occurs
– filling a pothole
– emergency milling
– sealing a crack
• Main purpose is to keep traffic moving
• Performed in harsh conditions
• Poor performance
Preventive maintenance
Preventive maintenance is the planned strategy of
cost effective treatments to an existing roadway
system and its appurtenances that preserves the
system, retards future deterioration,
and maintains or improves the functional
condition of the system.
Preventive maintenance
• Can be described as an organized
systematic process for applying a series of
treatments over the life of the pavement to
minimize life-cycle costs
• Is applying ...
• Anticipates ...
Preventive maintenance
• Can be described as ...
• Is applying the right treatment to the right
pavement at the right time
• Anticipates ...
Preventive maintenance
• Can be described as ...
• Preventive maintenance ...
• Anticipates pavement performance, and it is
applied in a timely manner to maintain or
improve service to the customer
Pavement Rehabilitation
Resurfacing, restoration, and rehabilitation work
undertaken to restore serviceability and to
extend the service life of an existing facility.
This may include recycling of existing
pavement, placement of additional surface
materials or other work necessary to return an
existing pavement, including shoulders, to a
condition of structural or functional adequacy.
Pavement Reconstruction
Construction of the equivalent of a new pavement
structure, which usually involves complete
removal and replacement of the existing
pavement section including new and/or
recycled materials.
DefinitionsC
on
ditio
n
Time
Rehabilitation
Preventive
Maintenance
Reconstruction
PM Treatments
Pavement
Preservation
Benefits of Preventive Maintenance
• Increased safety
• Cost saving
• Improvement pavement
condition
• Proactive vs. reactive strategy
Benefits of Preventive Maintenance
• Increase safety
– the number one priority for the travelling public
is safety
– preventive maintenance treatments ….
– implicit safety benefits are ...
Benefits of Preventive Maintenance
• Increase safety– the number one priority...
– preventive maintenance treatments provide
safer surfaces
• increase wet and dry weather surface friction
• reduce surface water spray
• reduce headlight glare from incoming traffic
– implicit safety benefits are...
Benefits of Preventive Maintenance
• Increase safety– the number one priority...
– preventive maintenance treatments...
– implicit safety benefits are obtained by keeping
the pavement in better overall condition
Benefits of Preventive Maintenance
• Cost savings
– savings are obtained
• better overall pavement condition - same cost
• same pavement condition - reduced cost
– reduction in...
Benefits of Preventive Maintenance
• Cost savings– savings are...
– reduction in user cost
• fewer delays - lower waiting cost
• smoother roads - lower vehicle operating cost
• safer roads - lower accident related cost
Benefits of Preventive Maintenance
• Improved pavement condition
– preventive maintenance treatments are designed
to be applied while the pavement is still in good
condition and help to maintain the pavement at
a high level of service
– treated pavements are...
Benefits of Preventive Maintenance
• Improved pavement condition
– preventive maintenance treatments are...
– treated pavements are smoother, have improved
frictional properties and last longer between
rehabilitation
Benefits of Preventive Maintenance
• Proactive vs. reactive strategy
– worst-first & routine maintenance
• repairs made to existing distresses
• most common approach to pavement maintenance
• common usage of “holding strategies”
– preventive...
Benefits of Preventive Maintenance
• Proactive vs. reactive strategy– worst-first...
– preventive maintenance
• preventive not reactive
• maintenance is performed before the appearance of
distresses
• added service life
Asset Management
• Pavement condition vs. time
• Balancing service life
Time
Con
ditio
n Preventive
Maintenance
Pavement
Rehabilitation
Pavement
Reconstruction
Area under the curve = Level of service
Pavement Condition vs. Time
Time
Con
ditio
n Preventive
Maintenance
Pavement
Rehabilitation
Pavement
Reconstruction
Pavement Condition vs. Time
Reconstruction
Preventive
Maintenance
Pavement
Rehabilitation
Pavement
Reconstruction
Time
Con
ditio
n
Pavement Condition vs. Time
Reconstruction & Rehabilitation
Pavement
Reconstruction
Preventive
Maintenance
Pavement
Rehabilitation
Time
Con
ditio
n
Pavement Condition vs. Time
Reconstruction, Rehabilitation & Preventive Maintenance
Reconstruction, Rehabilitation & Preventive Maintenance
Pavement Condition vs. Time
Conditio
n
Time
Reconstruction
Reconstruction & Rehabilitation
Agency & Industry Challenges
• Public perception
• Management perception
• Technical challenges
Agency & Industry Challenges
• Public perception
– preventive maintenance will steer work toward
pavements that are in relatively good condition
and away from pavement that are failing
– there is a…
– complaints are…
Agency & Industry Challenges
• Public perception– preventive maintenance will…
– there is a perception that the public will not
support a strategy that moves away from the
worst-first strategy
– complaints are…
Agency & Industry Challenges
• Public perception– preventive maintenance will…
– there is a…
– complaints are always specific to a particular
road and are never about the overall condition
of the road network
Agency & Industry Challenges
• Management perception
– the success of a “mix-of-fix” program requires
a commitment from top management
– because benefits of…
– short delay in applying a…
– more effort is needed to…
– agencies project the benefits…
Agency & Industry Challenges
• Management perception– the success of a…
– benefits are often not well defined, preventive
maintenance programs are, in many cases, not
able to compete with other programs
– short delay in applying a…
– more effort is needed to…
– agencies project the benefits…
Agency & Industry Challenges
• Management perception– the success of a…
– because benefits of…
– short delay in applying a needed treatment
can result in a significant increase in cost
– more effort is needed to…
– agencies project the benefits…
Agency & Industry Challenges
• Management perception– the success of a…
– because benefits of…
– short delay in applying a…
– more effort is needed to inform decision
makers of the benefits and cost-effectiveness
of mix-of-fix programs
– agencies project the benefits…
Agency & Industry Challenges
• Management perception– the success of a…
– because benefits of…
– short delay in applying a…
– more effort is needed to…
– agencies must evaluate benefits from such
programs by looking at the long-term
performance of their pavement network
Agency & Industry Challenges
• Technical challenges
– research is needed to clarify
• when should treatments be applied
• which treatments are appropriate
• what is the life extension gained
– research is also…
Agency & Industry Challenges
• Technical challenges– research is…
– research is also needed to improve the
performance of the existing treatments
Preventive Maintenance Treatments
• Crack treatments
• Surface treatments
• Recycling treatments
• Milling and thin overlays
• Emerging treatments
Crack Treatments
• Typically used to
– prevent water and debris
from entering individual
cracks in the HMA
pavement surface
Surface Treatments
• Typically used to:
– seal cracks
– waterproof surface
– improve friction
– improve rideability
– rejuvenate surface
• Treatments available
– fog seals
– slurry sealing systems
– micro-surfacing systems
– chip seals
Surface Treatments
• Fog seal
– light application of diluted,
slow-setting asphalt
emulsion without aggregate
cover
• Purpose
– seal pavement
– inhibit raveling
– enrich hardened/oxidized
asphalt
Surface Treatments
• Quick-set slurry seals
– mixture of well-graded
aggregate and quick setting
asphalt emulsion
• Purpose
– seal surface cracks
– correct raveling/oxidation
– fill minor surface
irregularities and restore
friction
Surface Treatments
• Micro-surfacing
– mixture of high-quality
aggregates and polymer-
modified emulsion binder
• Purpose
– inhibit raveling and surface
oxidation
– improve surface friction
– fill ruts/minor surface
irregularities
– seal pavement surface
Surface Treatments
• Chip seals
– application of asphalt and
aggregate chips rolled onto
the pavement
• Purpose
– seal pavement
– enrich hardened/oxidized
asphalt
– retard reflection cracking on
HMA overlays
– improve surface friction
Recycling Treatments
• Typically used to:
– rework HMA to a depth of
25 to 125 mm
– correct surface distresses
– improve profile, crown &
slope
• Treatments available
– Cold In-Place Recycling
– Hot In-Place Recycling
Recycling Treatments
• Cold In-place Recycling
– milling, rejuvenating, and
replacement of the top
portion of the HMA surface
(performed without heat)
• Purpose
– rework HMA to depth of 50
to 125 mm
– correct surface distresses
– improve profile, crown, and
cross-slope
Recycling Treatments
• Hot In-Place Recycling
– milling, rejuvenating, and
replacement of the top
portion of the HMA surface
(performed with heat)
• Purpose
– rework HMA to depth of 25
to 50 mm
– correct surface distresses
– improve profile, crown, and
cross-slope
Milling and Thin Overlay
• Typically used to:
– waterproof surface
– improve friction
– improve smoothness
– correct surface distresses
– improve profile,crown &
slope
Emerging Treatments
• Ultra-thin friction course
• Micro-milling and micro-surfacing
• Compound surface seals
• Single pass chip sealing systems
Emerging Treatments
• Ultra-thin friction course
– gap-graded, polymer-
modified HMA placed on a
heavy, polymer-modified
emulsified asphalt tack coat
• Purpose
– increase surface friction
– address surface distress
– reduce noise
Emerging Treatments
• Micro-milling and micro-
surfacing
– application of a micro-
surfacing wearing course
after micro-milling of the
top portion of the HMA
surface
• Purpose
– improve smoothness and
surface friction
– improve profile, crown, and
cross-slope
Emerging Treatments
• Compound surface seal
– membrane/chip seal applied
in a single pass
• Purpose
– seal pavement
– enrich hardened/oxidized
asphalt
– retard reflection cracking on
HMA overlays
– improve surface friction
Conclusions
• Pavement preservation and the usage of preventive maintenance represents a significant departure from the usual way of doing business.
• Preventive maintenance begins with the concept that the treatments are cost-effective and they are applied when the pavement is still in relatively good condition.
• Mix-of-fix philosophy focuses on the improvement of the road network, consequently, the overall value of the road network asset remains stable or increases over time.
