Curing for Quality Concrete

Concrete is the most important element of a building. The quality of the concrete must be maintained as it is the deciding factor of the life of a building structure.
People are very conscious regarding the quality of material sand aggregate and cement used in concrete; even about the water-cement ratio, slump, the temperature of the concrete during placement. During placing it is ensured that concrete is compacted properly. But somewhere curing is often ignored or taken for granted.
On many occasions, it has been found that the curing period of concrete elements, plasters, brickwork, etc are left to the discretion of the site staff. Improper curing is considered as one of the significant reasons for concrete failures in columns, beams, slabs, pavements, etc, evident in the form of cracks easily noticeable by the naked eyes. The vertical member like a column, in particular, is one of the most victimised RCC elements which must be carefully cured, as the entire load from the slabs and beams are supported by columns and transferred to the foundations. Unfortunately, adequate curing is not given much importance at most of the sites leading to a reduction in the durability of the structure.
Nowadays higher grades of concrete having more cement content are being used; but adequate water is not supplied to the concrete for the cement particles to react. This is where the cement is being wasted indirectly. If the cement content is higher there must be a continuous wet curing where the cement will react with water for bond formation to make the concrete as strong as possible. If the concrete gets to achieve its maximum strength in the first seven days it will directly increase the durability and overall quality of the concrete.
To produce high-quality concrete, active curing is necessary and according to ACI, the most effective method for highly wear resistant and durable concrete is wet curing for a period of 7 days. which is given by drip curing sheets. Uniform temperature should also be maintained throughout the concrete depth to avoid thermal shrinkage cracks. Also protective measures to control moisture loss from the concrete surface are essential to prevent plastic shrinkage cracks.

Concrete quality control is not just during the manufacturing of the concrete. It becomes very important after proper placement. Proper curing of laid concrete is very important. If not, then water that is for concrete bonding will evaporate and henceforth concrete strength drops down from the specified value.

Shrinkage is another aspect that occurs if quality control is not assured. Water evaporates and left empty spaces behind. Empty spaces create strain on the surface. Concrete try to restrain these strains but not do so. Therefore, cracks start propagating on the surface of concrete and hence the volume of concrete also decreases.

Conclusion: Curing is not only to make the concrete strong after its placement but it is the key which decides and ensures the durability and life of the concrete.

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