Curing can be defined as a process of keeping the concrete moist and warm enough so that the hydration of cement can continue. More elaborately, it can be described as the process of maintaining a satisfactory moisture content and a favorable temperature in concrete during the period immediately following placement., so that hydration of cement may continue until the desired properties are develop to a sufficient degree to meet the requirement of service.
Concrete derives its strength by the hydration of cement particles. The hydration of cement is not a momentary action but a process continuing for long time. Of course the rate of hydration is fast to start with, but continues over a very long time at a decreasing rate. The quantity of the product of the product of hydration and consequently the amount of gel formed depends upon the extent of hydration.
The requirement is increasing day by day as the need of high strength concrete is increasing. Note that the quality of concrete increases when there is a uninterrupted curing. Concrete while hydrating releases heat of hydration as it is a exothermic reaction , this heat may affect the quality and strength of concrete . So remove it by some means, and yes for that curing is a nice option.
There are different types of curing method available, Some of them are:
This is the most commonly used method . To start with, this method is the most efficient way. Apply water in the following way:
- Spraying or fogging
- Wet covering
Sometimes, concrete is inaccessible and in some places there is a acute shortage of water, there we use this type of curing method. In this method the surface of concrete is sealed using a sealing agent to reduce the amount of evaporation of water from concrete.
Application of heat
The strength of concrete not only depends upon the time but it also depends on the temperature. When concrete is subjected to higher temperature it accelerates the hydration process. Some of the commonly used methods are:
- Using steam at ordinary pressure.
- Using steam at high pressure.
- Curing by infra – red radiation.
- Electrical curing
Calcium chlorides used either as surface coating or as an admixture. We can use salt as a curing agent as it absorbs the moisture and helps to retain the moisture on the surface of concrete.
Check this post to Quality of water used in concrete mix .