C30/37 w/c 0.5 xc4+xf3 Must not be troweled?

[xLnT]

Aha okay. The dilemma we have is that we don't want the ballast visible, just polished concrete surface.

Then I think you should contact a floor grinding company and ask which concrete they recommend for your purpose.

You should also talk to your constructor and question why he recommended that concrete mix.

 

[Bubbenb]

What are you going to cast?
It doesn't matter if it is the middle of summer or winter, you can cast all year round if you have the right tools.
Air is used in the concrete to prevent it from cracking during winter when moisture enters the concrete and expands.
If you are casting a slab for a house, you don't need to use air, but if you are casting, for example, a carport, it will be exposed to cold, and that's why you want to have air.

 

[MackanM]

What are you casting?
It doesn't matter if it's in the middle of summer or winter; you can cast all year round if you have the right tools.
Air is used in the concrete to prevent it from cracking in winter when moisture enters and expands in the concrete.
If you're casting a slab for a house, you don't need to use air, but if you're casting something like a carport, cold can get to it, and therefore you want to have air.

I have googled all night about this and concluded that it's not needed. We will cover with plastic immediately after casting, then smooth out and spray with membrane cures, and then cover again with regular plastic.

What I'm wondering is if I need to worry that we won't have tight coverage during winter, but we will build all the time instead. We are building with blocks.

 

[xLnT]

I have googled all night about it and concluded that it is not necessary. We will cover with plastic immediately after casting, then trowel and spray curing compound and then cover again with regular plastic.

I'm wondering if I need to worry about not having a roof during winter as we will be building the whole time instead. We are building with blocks.

You don't need to worry about that.
We didn't have a roof or walls on our house the whole winter.

 

[Knight]

If there is a risk of freezing, a heating cable is used in the outer part of the slab.

 

[MackanM]

No below-zero temperatures for 4 weeks. Just an average of plus 8.

 

[Bubbenb]

So you don't need xf3 for a villa slab, simple as that. It's completely overly serious. As long as you don't have drying requirements, go with a k30. If you're planning to have, for example, a bathroom in the near future, you might need to think about drying, otherwise, go ahead.

 

[MackanM]

I mean, you don't need xf3 for a villa slab simple as that. It's absolutely over-serious. As long as you don't have drying requirements, go with a k30.
If you're planning to have, for example, a bathroom in the near future, then you might need to think about drying, otherwise go ahead.

It goes away on Monday when I call in. However, I will add for faster smoothing and extra heat accelerator.

 

[Bubbenb]

It leaves on Monday when I call in. However, I will add for Faster smoothing and extra heat accelerator.

Accelerator is not super necessary when it's so warm unless you want to smooth ultra-fast.

 

[MackanM]

The weather will be as follows. We will cast the first car at 7:30 AM.

 

[Bubbenb]

Yes, it is unlikely to freeze, now I cannot speak for all those who manufacture concrete but I would never recommend an aircrete for a villa slab, now I know that designers usually err on the side of caution.

 

[MackanM]

Absolutely right. Even my reinforcement is overdimensioned but I can live with that.

I will be without air and need to consider if I should have quick-hardening. I am planning to have finished concrete as the floor. Maybe it's enough that we cover it, which will speed up the process.

 

[Bubbenb]

If you want to have a bare concrete floor, you want the concrete to be as stiff as possible with as little cement as possible, as well as shrink-reducing additives to prevent cracks, preferably with large stones.

 

[Danne_83]

Absolutely right. Even my reinforcement is oversized but I can live with that

Seems silly to pay for a designer when you already know yourself how much reinforcement there should be?!

 

[bossespecial]

Absolutely agree that it is overboard with air mixing. If you're worried, you can always cover the slab to minimize the amount of precipitation that stays on it. Also, double-check with the engineer if you really need c30/37, as mentioned, the shrinkage decreases with less cement and consequently the reinforcement requirement in terms of cracks. By the way, has the engineer been informed that the slab is supposed to be the finished floor surface?
Statements that engineers just overdo it with belt and suspenders unfortunately show that one doesn't really know what they're talking about.