Entrained Air concrete 1

[5234185]

As we know, concrete is typically designed with 4 to 8 percent entrained air. What is the minimum percent of entrained air concrete should have in regions specifically southern states where concrete does not experience freeze-thaw cycles?

Thanks

 

[haynewp]

What is the application?

 

[Ron]

There are numerous reasons for air entrainment. Freeze-thaw resistance is only one. As haynewp says, we need more info.

 

[concretemasonry]

Concrete without an air entraining admix is usually 1% to 1 1/2% and sometimes higher depending on any other admixes.

Are you concerned with other expansion/shrinkage due to temperature, drying or unusual conditions.

Dick

 

[dik]

Entrained air helps with placing and finishing. If it's not required for freeze-thaw, I usually use 2% to 5% or spec 5% max. The 2% usually accounts for entrapped air and leaves some room for increasing workability.

Dik

 

[5234185]

Lets say concrete for rigid pavement!

 

[JAE]

Seems like you could check various DOT specs in states down south to see what they require in their mixes.

 

[Ron]

In the south, without exposure to freeze-thaw, then 3 to 5 percent would work fine. This will help consolidation and placement/workability. For rigid pavement, keep the slump as low as possible (preferably 2" max) and the water-cement ratio below 0.50. Dowel the lateral joints and make sure all joints are sealed after forming or sawcutting.

Tons more recommendations would apply to rigid pavement...these are just a few.

 

[darthsoilsguy2]

entrainment of air is one element of the creation of durable concrete. Concrete strength is also important for durability... i.e. most delivered commercial non-air mixes in USA are 3000 psi. however exterior concrete with air entrainment is more typically a 4000 psi mix.