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Asphalt parking lots are very expensive to install and have an effective life
of 7-12 years before expensive repairs must be undertaken.
Asphalt pavements
have two major weaknesses that lead to this limited lifetime.
1. First asphalt has
poor resistance to UV radiation or simply sunlight.
Asphalt pavements are a
simple combination of rock, sand, and a glue which is the liquid asphalt that
binds everything together. The UV radiation breaks down the asphalt glue and
weakens so that it can no longer hold the rocks and sand, thus gradually loosing
the top surface.
The first and most obvious sign of this degradation is the
gradual change in the color of the asphalt from black, to brown, and finally to
gray.
Next your parking lot begins to look rough and piles of sand seem to
appear in the low areas of the parking lot. This is not from your neighbors yard
but from the deterioration of your parking lot.
In the later stages of
degradation the bigger rocks fall out, raveling takes place, and the parking lot
is rough, extremely dirty because now dirt and grass fill the spaces where rocks
were.
Also because the asphalt is oxidizing under the UV radiation, it
looses its flexibility. This flexibility is extremely important because asphalt
can take great loads and bounce back to its original condition. As asphalt
looses its flexibility it becomes brittle and begins to crack and break.
2. The second major weakness of asphalt pavements is its poor resistance to
salts, chemicals, and petroleum products. |
