This CAI Approved Course is intended to educate association managers on the basic scientific elements of pavement preservation and deterioration and ways to manage them over time.

1. The Science of
Pavement Preservation
Chris Evers
cevers@pavetechinc.com
Ken Holton, P.E.
kholton@pavetechinc.com
Chas Jordan, ENV SP, LEED GA
cjordan@pavetechinc.com

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What is Pavement Preservation?
A cost-effective set of practices that
extend pavement life and improve safety
and motorist satisfaction while saving
public tax dollars.
(NCPP, pavementpreservation.org)

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Pavement Preservation
• Asset Management Principles:
• Life Cycle Cost Benefit
• Maintaining Early to keep in “Like New” Condition
• Pavement “Value”
• Preventive Maintenance
• Oil Changes?
• Change the Air Filter in your A/C Unit?
• Mow your lawn?
• All Examples of Preventive Maintenance

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FHWA Every Day Counts Initiative

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FHWA Every Day Counts Initiative

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“Right Treatment on the Right Road
at the Right Time”
Condition
Time
$1 for preventive
maintenance here
Is 3 to 10 times
more cost
effective than
here

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Real Science:
Why does Asphalt Deteriorate?
1. Age
2. Oxidation
3. Water Damage
4. Traffic Damage

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Why does Asphalt Deteriorate?
AGE (Hardening)
The first significant hardening of
the asphalt cement takes place
in the pugmill or drum mixer
where heated aggregate is
mixed with hot asphalt cement.
During this short mixing time,
the asphalt cement, which is in
very thin films, is exposed to
high temperatures ranging
from 275 to 350º F.

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Why does Asphalt Deteriorate?
OXIDATION
The roadway begins to
deteriorate the moment it’s
paved. The worst part is it’s
exponential. The viscosity of the
asphalt binder can go from 10-15K
poise when it’s only a few months
old to several hundred thousand
after only a few years. In Florida
this is how most roads fail.

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Why does Asphalt Deteriorate?
WATER DAMAGE
Seeps into asphalt,
especially cracks or
raveling. This water
expands and contracts,
causing distress in the
binder, and eventually
potholes or structural
damage occurs.

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Why does Asphalt Deteriorate?
TRAFFIC DAMAGE
Causes fatigue cracking
which can lead to heightened
damaged due to the
preceding elements. It also
compacts overtime, causing a
harder areas in the A.C. than
other areas of the roadway.

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Real Science:
How do we limit deterioration?
Thus, the secret of ensuring a
long service life of asphalt in
pavements is to retard the aging
process.

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How do we limit deterioration?

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Maltenes are the Key
• Maltenes are the unstable component
of asphalt binder and they are affected
by air, UV rays water, temperature, etc.
• It is the loss of the Maltenes from the
asphalt binder in the upper 3/8” to ½” of
asphalt pavements that start the
asphalt deterioration process.

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Deterioration
occurs as the
Asphaltic Cement
(AC) looses
Maltenes from
UV damage,
Water, and Traffic
over time.

16. Confirmed by FHWA – EDC Program

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Real Science:
So How do we Preserve?
• Depending on condition of the
pavement, it can be as simple as:
REPLACE THE MALTENES.
• Replacing the Maltenes can provide the
aged asphalt binder the materials
needed to remain fluid, viscous, and
healthy.

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Replacing the Maltenes:
Rejuvenation
Maltene based rejuvenators work by
changing the chemistry of the asphalt
binder by replenishing the lost maltenes
back into the asphalt binder restoring its
asphaltene to maltene ratio back to
nearly new levels

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Rejuvenation
Fog Seal COATING -
Seals the surface
Petroleum Maltene Based REJUVENATOR -
Penetrates down into pavement & seals the surface, CANNOT be worn
away

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Real Science:
How do we know this works?
• The “Rostler Method” - Determines the
rejuvenator efficacy and determines
the ratio of resinous to oily maltenes in
the pavement surface
• ASTM Test D-2006-70 – “Free Maltene
Distribution”

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How do we know this works?
• Viscosity Testing
with a Dynamic
Sheer
Rheometer
(DSR)
• Higher Viscosity
means healthier
pavement

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How do we know this works?
• Measuring
International
Roughness
Index of the
Pavement
before and after
treatments

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How do we know this works?
• 3D Imaging Data – Mapping distress in
pavement based upon depth
differences at microscopic levels

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Real Science:
Is Rejuvenation what we need?
• Preservation can go beyond
rejuvenation, especially if pavement
shows signs of distress like:
• Cracking
• Severe Raveling
• Potholes
• Aggregate Loss

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How do I preserve?
• Through a mutual use of Maltene
replacement technology and:
• Crack Sealing
• Microsurfacing
• Seal Coating
• Chip Sealing
• Slurry Sealing

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Why with other treatments?
• The Maltenes will benefit the existing
Asphaltic Cement, however due to the
distress in the existing road, a new
wearing surface is needed or at the
very least, crack sealing to limit water
intrusion below the top layer of
asphalt.

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Real Science:
Has this been proven, and by who?
• National Center for Pavement
Preservation at Michigan State
University (pavementpreservation.org)
• Center for Multidisciplinary Research in
Transportation at Texas Tech University
• Time and Experience

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Real Science. Real Results.
www.pavetechinc.com