User:Smsarmad/Concrete curing

Concrete Curing is a method of maintaining concrete moisturized for a certain period of time. It is started when the concrete hardens after it is laid to set. Curing increases the durability, strength, water-tightness, abrasion resistance, volume stability, resistance to freezing, thawing and shrinking of the concrete by slowing down the moisture loss and carbonation of the concrete.

Research
A technical committee of International Union of Laboratories and Experts in Construction Materials, Systems, and Structures (RILEM) has been studying the methods of curing that can reduce the shrinking of concrete.

Hydration
When cement is mixed with water, a chemical and physical reaction called hydration takes place. which bonds together the mixture particles. The concrete thus formed contains pores, which are reduced by the hydration process that spans over a vast time and also increases concrete's strength.

Curing methods
Curing is done in a number of ways, depending on the material available and the strength of the concrete required to be achieved.

Water curing
Water curing is done by either spraying water on the concrete or making water to stand over the concrete like a pond, if allowable.

Coverings
Coverings are laid on the concrete surface to entrap the moisture inside. Wet coverings like burlap, moist hay, straw, sand, earth, which are laid on concrete retain the moisture after being watered regularly. Artificial coverings like waterproof paper, polyethylene film and other plastic sheet material are also used for concrete curing.

Curing agents
Different agents/compounds used for curing, are premixed in the concrete mixture. These compounds by their classification either slowly release water while acting as a water storage (also known as water entrainment) or retains the water already held by the mixture. Concretes with a low water to cement ratio that are made for high performance and have high strength mostly don't have enough water required for the hydration, thus requiring the former type of curing agents that acts as water reservoirs.