Air Entrained concrete for internal Freezer Room Topping Slab with forklift traffic? 2

[MJNeedHelp]

Is air entrained concrete recommended for Freezer room topping slabs? I know it is recommended for concrete exposed to freezing and thawing cycles ... but not sure what is recommended for concrete that is below freezing temperatures permanently (therefore it does not cycle through freeze and thaw situations) and on an internal warehouse floor exposed to non-pneumatic wheel forklift traffic.
What would be the effect of specifying air entrained concrete in this situation?
What effect can this have on the surface when freezing - especially when a steel trowel finish is desired for hard wheeled forklift traffic? I've found it can increase the risk of blistering and delaminations. Has anyone experienced this?
Is there any other type of finish that can be specified to eliminate the risk of delamination that is ok for hard wheeled forklift traffic?
What is the compressive strength that would be required in this instance? I thought 32MPa, if there was no forklift traffic, but 40PMa with hard wheeled traffic ...but does the air entrainment cause a loss in strength and therefore a higher grade than 40MPa might be necessary for the areas exposed to forklift traffic to meet the required level of abrasion resistance?
Should any sealers or coatings be applied to the surface prior to us or not?
Any help in this area would be appreciated.

 

[JAE]

Steel troweling and air entrainment do not go well together - blistering is a very high probability.
I've had this happen to me once when a contractor insisted on using air in a mix so they could pump it easier.
They ended up grinding down 1 1/2" of slab (100,000 s.f. of it) and paying for a new bonded topping.

 

[JAE]

Check these out:

http://www.concretecolorado.com/resources/files//Concrete_in_Practice_Series/20p.pdf

http://www.cmc-concrete.com/CMC Pub...n - A sometime curse of entrained air, CC.pdf

http://www.concreteconstruction.net...ir-Entrained Concrete Floors_tcm45-343501.pdf

 

[dik]

Great response, J...

 

[MJNeedHelp]

Thanks Jae ... those articles are very useful!
I'd really like any information relating to the requirement for air entrained concrete in a freezer topping slab ... I'm in Northern Australia so there is no problem with freezing whilst the concrete is curing and hardening. We can take the temp down slowly once the concrete is mature (>28 days?). I've read some recommend to have air entrainment of no more than 3% for internal applications like this, and others have suggested no air is required at all if there are no freezing "cycles." this warehouse will be turned on and will stay frozen! Given the problems with steel trowelling air entrained concrete I'm tending to think we will leave out the air. Any thoughts? Are there any disadvantages in doing this?

 

[hokie66]

This reference says that air entraining for freezer floors is generally not recommended.

http://www.concrete.org/FAQ/afmviewfaq.asp?faqid=593

 

[MJNeedHelp]

Thanks hokie66 I had seen this article ... just unsure why some would recommend air in this instance. Trying to get my head around it.
Would any coatings be recommended to protect / harden the surface exposed to freezing temps for hard wheeled high reach forklift traffic prior to use?

 

[hokie66]

Suggest you converse with Sika. They do advertise some of their flooring materials as being suitable for cold storage applications.

 

[flight7]

Air entrainment is usually recommended for concrete exposed to freeze-thaw cycles in an uncontrolled environment (in other words weather, including precipitation). Inside a freezer room, it should be uncommon to encounter freeze/thaw while the concrete is moist.