Asphalt pavements such as roads and parking lots are continually
being constructed but unfortunately are not lasting as long as they
used to. Many of us remember pavements lasting 15, 20 years or more
with little to no maintenance. In February, 1995, Road and Bridges
magazine reported that “The average service life of an Ohio
road is 8.2 years.” This information was taken from an Ohio
Department of Transportation study that monitored roadways and maintenance.
Why this drastic decline in asphalt and roadway life?
A) Traffic
Since 1980, vehicle miles traveled has increased 80%
Many of us commute an hour each way to work. Drop-off and pick-up
the kids at day care 15 minutes each way and then go out to eat
across town 20 minutes each way and think nothing of it.
Yet in the same 20-year period our total number of lane miles
has only increased by 4%.
Today there are 40% more registered vehicles that in 1980.
This all adds up to a greatly over crowded highway/road
system. B) Asphalt
Asphalt is not as good as it used to be. Due to technological advances
in the refining process more and more of the high value resins and
oils have been extracted.
These resins and oils have a much higher dollar value alone than
in asphalt. They can be used in hundreds of products from plastics,
synthetic rubbers, perfumes and cosmetics. The asphalt in our roads
is merely the glue that holds the rocks together, the more they
refine from asphalt, the poorer the glue, the poorer the road.
We are continuously rebuilding and repairing our roads with an
asphalt of lower quality which continues to increase in price. C) Oxidation
Good design and quality construction can solve the traffic problem
easily enough. Therefore, we must focus on the fact that our asphalt
binder is not of the quality that it was in the past.
With new refining processes, asphalt is losing resins, which
makes it more susceptible to oxidation from the weather. Oxidation
happens when oxygen, in the air and water, chemically attacks
the asphalt binder causing it to breakdown.
Ultra-violet rays from the sun cause further breakdowns of asphalt
making it brittle. The freeze-thaw cycles associated with winter
and spring, in some areas, literally tear asphalt pavements apart
from the inside out. As much as 60% of the life of asphalt pavements
is lost in the first two years through oxidation. D)
Put it All Together
TRAFFIC
We are rebuilding and repaving more
and more roads due to the increased traffic demands,
ASPHALT
with an asphalt of lower quality and
higher price,
OXIDATION that oxidizes quicker.
And we’re trying to do it with a static tax dollar.
No one wants more taxes and more waste of tax dollars.
Our asphalt pavements are depreciating faster than we can replace
them. And most budgets are only half of what is required to keep
up.
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