Mix your own quick-drying concrete?

[ktm250]

jon_h: keep in mind that you speak quickly, low RF while the others speak fast durability... different things.

 

[LLLVäxjö]

jon_h: remember that you speak quickly, low RF while others talk about quick strength... different things.

But aren't those two things going hand in hand?

The lower w/c ratio you have in the concrete, the less excess water there is, while the strength growth curve becomes a bit steeper.

http://www.swerock.se/Produkter/Betong/Betongtyper/Snabbuttorkande_betong

I have read that if you go below 0.35 in w/c ratio, the concrete is nearly free of construction moisture.

Edit: or 0.32 according to this: http://www.betongbanken.se/index.aspx?s=2925

 

[LLLVäxjö]

Thank you for the reply and, of course, I do it at my own risk. If I were to mix in flyt, do you have suggestions on what and how much? A friend suggested I should mix in steel fiber as reinforcement, but I'm a bit uncertain...

/Andreas

I've now got hold of some 0-8 crushed material to try with, and without flyt, it turned into something that can only very generously be called concrete (if you aim for wcr under 0.6 with that recipe). With 0.5% flyt (10g), it became, as expected, quite different and looked clearly usable. I have a test cube "baking" now, and I'll get back with the strength results.

I made another one just now with 1% flyt instead. Wcr became 0.52 for roughly the same consistency. Since these are small batches mixed in a bucket by hand, you can't rely a hundred percent on my tests, but it probably gives an indication at least

 

[LLLVäxjö]

Now I've gotten hold of some 0-8 crush to try with, and without fluid it became something that with a lot of goodwill can be called concrete (if you want to go below w/c ratio 0.6 with that recipe). With 0.5% fluid (10g) it turned out much better as expected and looked clearly usable. I have a test cube "baking" now, will update with its strength.

Just made another one with 1% fluid instead. The w/c ratio was 0.52 for roughly the same consistency. Since these are such small batches mixed in a bucket by hand, I can't rely 100% on my tests, but it should give an indication anyway

The first cube held 34MPa after 7 days, final strength about 42MPa.

The second held 54 MPa at the same time, expected final strength about 67 MPa.

 

[aivo]

Thanks for the info. That was really cool of you!