If a concrete surface is not treated, and is subject to weathering, it can break up.
Steven Lambert -
One of the biggest problems faced by any piece of concrete is the effect water will have on it. The most obvious
sign is staining. This can result in algae or black spots, and can lead finally to cracks. So the only way of
combating this, is to use a concrete sealer.
If a concrete surface is not treated, and is subject to weathering, it can break up and results in what is know as
spalling. This is where the aggregates in the concrete come through and begin breaking back down.
The effect of water on concrete can be described in two ways. Positive, is from rain fall, and Negative is from
ground water. Either way, the moisture and vapour will transmit itself through the concrete Concrete behaves like a
sponge with water. The water will always travel through it, seeking the dryer areas, until it reaches the air.
Finally the only way of stopping it, is to form a membrane across the surface.
The way water can break down a piece of concrete is not complicated. Basically it undergoes alkali disintegration,
which lies dormant, and no longer reacts with the Portland in the cement. As the water hydrates, the alkali begins
to react with the cement around it to turn back into a powder, or efflorescence.
When mould takes hold of concrete it can lead to sever health problems for those living near it. Mildew and mould
can produce a fungus which releases Myotoxins. These can be deadly if taken inside the body. Sealing the concrete
is one very good solution.
One of the chemicals used in concrete a sealant, is Polysiloxane. This is used as curing agents with epoxies to
generate flexible, moisture and weather resistant coatings.
These can result not only in saving a concrete surface, but can make a pathway or drive easier to keep
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