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 type of curing materials used on projects is critical to the proper performance of the final product.
The Standard Practice for Curing Concrete (ACI 308) lists several methods by which adequate curing can be achieved:
ACI 308 also lists several non-water curing methods such as application of application of plastic film, reinforced paper, and liquid membrane-forming compounds.
Water Curing Specifications
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.