[sunil zende]

Curing

The process of maintaining moisture in the concrete is called curing. Concrete begins to dry after casting. So, the parts exposed to the environment should be cured to ensure that the concrete surface is never dry. This needs to be done continuously, till the mandated period of curing. Usually, 10-14 days of curing is considered optimal. It is best to make small curing ponds or bunds on flat or horizontal surfaces. For vertical surfaces, you may wrap jute or hessian cloth on the surface and then pour water onto it. This helps keep the surface wet for longer periods.

[fdaforum]

For RCC slab construction no construction work should be done for at least three days after casting of slab . Curing should be carried out for minimum 7 days for all cement and concrete works. Better curing gives extra strength without any extra cost.
FD Architects Forum

[Manish Jain]

Methods of curing


• Water curing 
This is the best method of curing as it satisfies all the requirement of curing, namely, promotion of hydration, elimination of shrinkage and absorption of heat of hydration. It is pointed out that even if the membrane method is adopted it is desirable that a certain extent of water curing is done before the concrete is covered with membrane 

• Immersion
  
• Ponding
  
• Spraying or fogging
  
• Wet covering
  

• Membrane curing
• Appplication of heat
• Miscellaneous 


Duration of curing

• The concrete should not be allowed to dry fast in any conditions.
• This conditions should be maintained for 24 hours.
• The best practice is to keep the concrete in gunny bags
for 24 hours and then commence water curing by ponding or sprinkling method.
• The concrete cured for the long time will show superior strength and show other good properties.
• However ,curing for long time will be a costlier process.
• The curing period varies for different structures ,situation and different atmospheric temperature.
• So for general it is cured for 7 days