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Curing is defined as maintaining a satisfactory moisture content and
temperature in concrete during its early stages to develop desired properties.
These properties include strength and permeability, plus resistance to scaling,
abrasion, sulfate attack, carbonation, and alkali-aggregate reactions (ASR). The
Standard Practice for Curing Concrete (ACI 308) lists several methods by which
adequate curing can be achieved: Water curing through ponding or immersion;
fog-spraying or sprinkling; burlap, cotton mats or rugs; earth curing; wet sand
and sawdust; and straw or hay. ACI 308 also lists several non-water curing
methods such as application of plastic film, reinforced paper, and liquid
membrane-forming compounds.
TxDOT specifications for water curing allows the use of wet cotton mats, ponding
or spraying. If the air temperature is expected to be below 40 degrees
Fahrenheit, polyethylene sheeting (in conjunction with other insulated mats),
burlap-polyethylene blankets, laminated mats, or insulated curing mats are
required, as well. These products should not be used in warm weather as they can
artificially raise the concrete temperature and cause damage to the concrete.
Black plastic should not be used to replace clear or opaque white polyethylene
sheeting if the air temperature during the curing period will exceed 60 degrees
Fahrenheit.
The type of curing materials used on projects is critical to the proper
performance of the final product. For further information, call Brian Merrill at
(512) 416-2232.
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