What is Curing of Concrete?- | Importance | Methods

What is Curing of Concrete?

Curing is the process of maintaining the moisture of freshly placed concrete to complete the hydration process and to ensure proper hardening, attaining desirable strength and durability. Curing keeps the concrete surface moist and reduces the shrinkage. Curing should be started at the earliest. It has to be started when the surface is hard enough for a person to walk over it without damage to concrete. Till such time the surface moisture may be maintained by splashing or spraying water without force.

 

                                                                              In fact, concrete derives strength by the hydration of cement. If curing is neglected in the early period of hydration, the quality of concrete will experience a sort of loss. If curing is not done well after placing of concrete, it will not give the desirable bond and strength characteristics.

Importance of Curing

The curing protects the concrete surface from sun and wind. Curing imparts better strength to the concrete. The durability and impermeability of concrete are increased by proper curing.
                                                                                 For the ordinary portland cement, the curing period is about 7 to 14 days. If curing of concrete is not done properly it will reduce the compressive and flexural strengths. The frost and weathering resistances are decreased due to improper curing. The cracks are developed due to plastic shrinkage, drying shrinkage and thermal effects if curing is not done properly.

Method of Curing

The most common method of curing are as follows:
  1. Water Curing
  2. Membrane Curing
  3. Application of heat/steam Curing
  4. Application of Curing Compound

Water Curing

It is the best method of curing. In this method, water is applied on the concrete surface for certain duration. There are the following ways of water curing.

  1. Ponding
  2. Spraying


Wet covering slabs, roofs etc. are covered underwater by developing water pond on the concrete surfaces. Vertical walls, columns, plastered surfaces are cured by the sprinkling of water on it. Vertical surfaces are also cured by using some wet covering such as gunny bags, cloth, jute matting, straw etc. horizontal surfaces are kept wet by covering concrete with wet sand, sawdust etc.

Membrane Curing

In some places where there is an acute shortage of water, membrane curing is adopted. Generally, water mixed for making concrete is more than sufficient to hydrate the cement. Membranes are applied all around the concrete which will effectively seal off the concrete. The membranes seal over the concrete by means of a firm impervious film to prevent moisture in concrete from escaping by evaporation. This prevention of moisture in the concrete will work as curing of concrete.


Application of heat/Steam Curing

When concrete is subjected to a higher temperature, with an excess of moisture it accelerates the hydration process and results in the higher development of strength. Therefore for achieving this goal concrete is required to subject the steam curing.

Application of curing compound

There are certain curing compounds that keep the concrete wet. Calcium chloride is the one curing compound. It can be used as a surface coating. Calcium chloride is a salt, it shows an affinity for moisture. Salt keeps the concrete wet for a long time to promote hydration.



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Also, read -

Compressive Strength of Cement Concrete
Concrete Mix Ratio For Various Grade Of Concrete

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