Hi rusebud,
Not to worry, you no doubt are observing the natural process of
efflorescence on your new pavers caused by moisture reacting with
natural salts and it will correct itself in time.
Understanding And Managing Efflorescence On Concrete Pavers by Joe Fitzpatrick :
"At the time of installation and up to a few weeks or months, a white
haze known as efflorescence may appear on the surface of concrete
pavers. It may appear randomly or in certain areas, and will be more
pronounced on dark colors. The haze may give the impression that the
color of the pavers is fading. When wet, the white disappears and the
color is enhanced. If when dry, the haze reappears, it is a sure sign
of efflorescence."
[see photo]
"The pavers are neither damaged nor defective but rather are
experiencing a natural process ? a condition in all cement-based
products. The condition will disappear with time.
All concrete products contain cement, which produces lime or
water-soluble calcium oxide. Lime can also be in the bedding sand,
aggregate base materials or soil. Stone dust is a base material that
is not recommended. It also contains lime and retains water. Although
concrete pavers are very dense, they contain millions of microscopic
capillaries that run from the interior to the surface. When moisture
enters these microscopic capillaries, calcium oxide inside the paver
reacts with the water in the capillaries and forms calcium hydroxide.
This rises to the surface, reacts with the carbon dioxide in the air
and forms a white haze of calcium carbonate. When moisture on the
surface evaporates, the white haze of efflorescence becomes visible.
It will stop when no more calcium hydroxide is available to move to
the surface."
http://www.cambridgepavers.com/News/news6_2004.html
ICPI (Interlocking Concrete Pavement Institute)
:Tech Spec 5, Cleaning and Sealing Interlocking Concrete Pavement?A
Maintenance and Protection Guide.:
* What is Efflorescence?
"A white haze that may appear on the surface of the pavers. It may
appear randomly or in certain areas, and will be more pronounced on
dark colored pavers. The white haze may give the impression that the
color of the pavers is fading. When wet, the white disappears and the
color of the pavers is enhanced. When they dry, the white haze
reappears.
* When will Efflorescence Stop?
When the supply of calcium hydroxide is exhausted. If you live in an
area of frequent rain and sunny days, efflorescence and its passing
may occur quickly. The process may take much longer in drier
climates. Typically, efflorescence will stop developing in
approximately 18 to 24 months.
* Will it go away Naturally?
Since many factors are involved in its formation, it is difficult to
determine when efflorescence will eventually disappear. Over time,
rainwater can wash and wear it away.."
* Efflorescence is Completely natural and will disappear with time
There?s no reason to be concerned that your pavers are damaged or
defective. The concrete pavers are experiencing
a natural process. It is a condition in all cement based products, as
well as in many other paving products..."
* The Chemistry of Efflorescence
All concrete products contain cement which produces lime or water
soluble calcium oxide. Lime can also be in the bedding sand, aggregate
base materials, or soil. Although concrete pavers are solid, strong,
and very dense, they contain millions of microscopic capillaries that
run from the interior to the surface. Moisture from rain, sprinkler
systems, underground sources, poor site drainage, or dew enters these
microscopic capillaries.
Calcium oxide inside the paver reacts with the water in the
capillaries and forms calcium hydroxide. This rises to the surface,
reacts with the carbon dioxide in the air, and forms a white haze of
calcium carbonate. When moisture on the surface evaporates, the white
haze of efflorescence becomes visible.
* Can it be removed without the wait?
Yes, efflorescence may be cleaned with commerically available cleaners
formulated specifically for concrete pavers. Cleaning should be
performed immediately after efflorescence has appeared. It may
reappear as long as the chemical reaction continues and cleaning may
need to be done until efflorescence has stopped..."
http://www.icpi.org/myproject/Efflorescence%20brochure.pdf
My new pavers have a white haze on them. What is it and how do I get rid of it?
The white haze is most likely efflorescence which occurs when the
natural salts in the raw materials settle on the surface of the paver.
This is common with all masonry products. Surface moisture acts as a
wick to draw out these salts. The best course of action is to do
nothing; natural weathering will remove the efflorescence generally
within 6-12 months..."
http://www.woodburycement.com/pavers%20q%20and%20a.htm
What is efflorescence?
"Efflorescence is a white haze that may appear on the surface of
concrete pavers after a few weeks or months. Efflorescence is
completely natural and will disappear with time. Your products are
not damaged or defective. Efflorescence is produced by cement which
is a necessary ingredient in all concrete products.
Can efflorescence be removed without the wait?
Yes. Efflorescence will eventually go away naturally, but there are
commercial cleaners available that are specifically formulated for
concrete pavers. Most cleaners contain acid and detergents, so be
sure to follow all label directions and environmental regulations when
using these cleaners."
http://www.davisblock.com/patio_pavers.htm
My new pavers seem to have a film on them. What do I do to get rid of it?
The film on your pavers is caused by moisture and natural salts
settling on the surface of your pavers. The best thing to do is
nothing, letting it naturally weather on its own."
http://www.interlock-concrete.com/pavers/faq.php
I was glad to find this for you and I hope I've been able to set your
mind to rest. If you have any questions or if you don't think this
addresses your particular situation, please post a clarification
request *before* closing/rating my answer and I'll be happy to reply.
Thank you,
hummer
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