How to Mix And Cure Concrete
When Portland cement is mixed with water a chemical reaction
takes place .The cement does not simply "dry" it reacts with the water
to form crystals. These crystals bind the materials in a concrete mix
firmly together and harden into an incredibly strong rock like mass. It
takes some time and the optimum temperature for the best crystal
formation in the cement. If the temperature is too low crystals will
not form well or will form very slowly. The concrete will dry and
harden slowly and will not be as strong as concrete formed at an
optimum temperature.
When you manufacture concrete blocks or any other concrete
products the temperature should not drop below 40 degrees Fahrenheit (5
degrees Centigrade) and ideally should be 50 degrees (10 degrees
Centigrade) or higher. This allows the cement crystals to form properly
and bind the concrete mix strongly together.
You will often hear the term "curing concrete" used. This simply refers
to the time which the concrete needs to form an optimum bond after it
has been mixed with water. In other words this is the time needed for
the concrete to reach maximum hardness. The surface of the concrete
needs to be kept damp during the curing process or the outer layer of
the product will not harden properly and could crumble. This is why
concrete is sprayed down with water while it cures.The concrete must be
kept wet to cure properly.
The strength of the concrete depends on the proper growth of the
cement crystals within the mix. If the crystals don't grow
properly due to the wrong amount of water being added,or to the
temperature being too low, the concrete will not have the full strength
that it should have. You will be depending on your concrete structures
to withstand all kinds of weather and temperature changes. In order to
achieve this you need to have optimum crystal growth within the
concrete mixture.
For best crystal growth you must have the correct proportion of
water in the concrete mix. If there is insufficient water the crystals
will not grow. If the temperature is too low the crystals will not grow
well either. If the temperature is too high the crystals grow too
quickly and the chemical reaction produces heat which can lead to
cracking of the concrete product. With the correct proportion of water
in the mix the crystals grow properly and bond the concrete by
intertwining round the sand and gravel.
When you make concrete products you need the curing to take place as
quickly as possible to get your products delivered to the customer.
This is achieved by using the correct concrete mix with the right
proportion of water added to it. All ingredients of the concrete mix
must be carefully measured in the right proportions before mixing them
together. In addition the surface of the concrete must be kept damp and
the temperature at above 40 degrees Fahrenheit.
Another factor which determines the strength and hardness of the
finished concrete product is proper mixing of the ingredients. If
the ingredients are not thoroughly mixed there will be differing
degrees of hardness in various parts of the finished product. Needless
to say this is something to avoid at all costs. The dry ingredients of
the concrete mix should be thoroughly mixed before adding water. This
is particularly true if you are mixing the concrete by hand on the
ground. You should very thoroughly combine all the ingredients of the
mix into a homogenous mixture before adding the water. Using a
mechanical concrete mixer helps to make sure that the concrete is
thoroughly combined before pouring.

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