The
Major Threats To Asphalt Pavement
Properly made asphalt
pavements rarely weaken and deteriorate from traffic wear. Instead,
pavement deterioration is caused by petroleum spills, oxidation and
water intrusion.
Petroleum products that spill,
may dissolve
asphalt fines, reducing the binding power of aggregates and causing
the pavement to fail.
The sun will oxidize asphalt and begin
evaporating oils that bind aggregates. As a result, the pavement
becomes brittle, cracks and exposes the sub surface. Eventually this
raveling and erosion can reduce the thickness by as much as one-half
over five years.
During the freeze thaw cycles that are inherent to our area, the
strength of asphalt is weakened as the expansion and contraction of
the ice loosens aggregates. Water enters the cracks and exposed
areas, works its way into the sub grade and softens the base.
Ultimately the base begins to buckle under normal traffic loads.
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Pavement
Maintenance:
What Is It?
New
asphalt pavements appear to be dense and hard but they are
actually rather porous and begin to deteriorate within days of
installation.
A regular program of pavement maintenance that
includes cleaning, cracksealing and sealcoating typically doubles
the life of asphalt pavement.
Sealing the cracks with a rubberized
cracksealing material will protect the subsurface from moisture,
the primary enemy to asphalt.
After all the cracks have been filled,
sealcoating the pavement will protect the surface from moisture
penetration, petroleum spills, and ultraviolet rays that
oxidize the asphalt and makes it brittle.
When
Should I Begin?
To get maximum
life from asphalt pavement, maintenannce needs to begin soon after the
pavement is installed or repaired. After allowing 60-90 days for the
pavement to fully cure, the pavement should be sealed. Sealer applied
before the pavement is cured, may not adhere properly. Any cracks ¼ inch
or wide or larger needs to be sealed with a rubberized cracksealer and
continually maintained.
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What
is the Life Of Your Asphalt Pavement?
The condition of
the asphalt before sealcoating determines how long a sealcoat will last.
Typically, and asphalt surface that has been well maintained will hold
a sealcoat better than one that has been neglected.
Another factor in the life of your asphalt is the amount of traffic
that drives on the pavement. Sealcoat applications on residential driveways
usually last five years or more, while applications at a fast-food restaurant
may last as little as one year.
In order to extend the life of a sealcoat application the pavement needs
to be kept free from dirt and debris after the sealcoating is applied.
Sand and gravel is especially destructive if left on the pavement for
an extended period of time. If applied properly, the average two-coat
application will last approximately three years. However, the life of
the coating can be extended by incorporating latex additives and sand
into the emulsion before the sealcoat is applied
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