Cure time for concrete in freezer 1

[braves25]

I have a condition where a new concrete freezer slab will be placed at an existing building. How long does the contractor need to wait until using the freezer again? 7 days for proper cure time? Thanks!

 

[Ron]

Allow the concrete to cure, preferably for this case by using curing methods that prevent moisture loss and not by adding moisture to the concrete. I would cure for at least 14 days.

After curing, a temperature drawdown schedule should be followed to prevent excess cracking from thermal shrinkage and to allow moisture to be removed from the concrete more slowly to mitigate drying shrinkage and to dehumidify before reaching freezing temperatures.

ACI 302 has recommendations for a drawdown schedule (assuming you are in the US).

 

[braves25]

Thanks. One thing to note...this freezer is in a store that is in operation...anyway to reduce the 14 day period? Looking at ACI 306 Cold Weather Concreting for max allowable temp drop after "protection period".

 

[lsmfse]

We had a similar situation. The concrete mix was similar to what is used on freeways, sets up in 4-6 hours and is ready to drive on. We required 7 days cure prior to start up of the freezer. The freezer was slowly brought into service.

 

[JacksPanic]

Are you replacing the entire slab whilst the freezer store is in operation? Or are you adding to an existing slab? Are there forklifts or other heavy machinery operating on these floors?

You will have to consider phasing of work as well as treatment of joints. Also a temperature drawdown schedule will have to be implemented. The guy responsible for the mix design should be able to give you curing,shrinkage,etc. Parameters.