Curing is the process by which moist conditions are maintained on the finished concrete surfaces in order to promote continued hydration of cement. If proper curing is not done, complete hydration of cement will not take place, which will badly affect the strength of the concrete.
Importance of curing:
Proper curing of concrete is very much important. Not only concrete but also cement plaster, brickwork and other works wherever cement as binding material has been used, curing is required to be done very essentially. However, the importance of curing is furnished below.
- Curing increases the strength of the concrete with time.
- It improves the durability of the concrete.
- It makes concrete water tight by minimizing the cracks developed by shrinkage during drying.
Time to start and duration of curing:
Curing should be started after completion of final setting of the concrete. Usually concrete takes 10 hrs to finally set itself. Though the duration of curing depends upon the grade or mix proportion of the concrete and type of cement used in the concrete, but it should be done at least for 7 days from the date of laying concrete.
Method of curing:
There are several methods of curing depending upon the nature of work and climatic conditions. The most common methods of curing are listed below.
1) Ponding method:
It is the best method of curing the horizontal surfaces such as floors, roof slabs etc. In this method, the area to be cured is divided into small rectangular kearies with help of lean cement sand mortar or clay bunds. After drying of these bunds, water is filled in the kearies and kept filled for the period of curing.
2) Wet covering method:
This type of curing is very much suitable for vertical or sloping surfaces. In this method the surface to be cured is covered by wet gunny bags or hessian. These coverings are kept wet till the period of curing.
3) Sprinking method:
This method of curing is done on the vertical surfaces where it is not possible to provide wet coverings.
In this method water is sprinkled on the surface at suitable intervals. This type of curing requires large quantity of water.