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Posted by on October 30, 2006, 4:03 pm
Common Surface Defects
Concrete which has been damaged by cold weather commonly has surface
defects. The most common defect is spalling. Spalling is simply the
peeling or loss of the top finished layer of the concrete. It usually
happens because the upper surface of the concrete froze before enough
crystals grew to give this layer a strength of 500 PSI.
Popouts are another common surface defect. A popout is created when a
piece of aggregate (rock) in the upper surface of the concrete explodes
as a result of freezing. Some pieces of aggregate have a tendency to
absorb water. This water freezes, expands and BOOM! Gravel companies go
to great lengths to try to remove this type of rock from the gravel.
However, they don't always catch every piece.
Deicing salt damage is another common surface defect related to cold
weather. Scaling of your concrete can happen even if everything was
done correctly. As concrete is exposed to air, it gets harder. This
process is called carbonation. The carbon dioxide in the air reacts
with the concrete and creates limestone (calcium carbonate). Some forms
of limestone are very hard!
This carbonation process, however, usually takes one year to produce
any substantial differences in strength. So, if you use deicing salts
or they drip from the under side of your car onto your new slab, you
may have a problem.
Popouts can also be caused by dirty aggregates.
This might help.
http://www.vseal.com/surfacedefects/surfacedefects.php
Patch wrote:
> My 15 year driveway is starting to look pretty bad with all the pock-marks
> caused by water freezing and causing dime sized holes to appear on the
> surface. Is there a product that I can use to patch these holes? I try to
> seal the drive each winter, but sometimes I get caught by a hard freeze.
>
>
>
> --
> Posted via a free Usenet account from http://www.teranews.com
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