Can you sweeten the concrete?

[d_nilsson]

I'm going to pour a floor in the basement, about 7m^2, so approximately 700 liters of concrete. It's a bit too little to bring in a truck with a pump, even though that has been very convenient on the slightly larger floors I've already done. I'm considering renting a larger mixer and trying to mix it myself, but I would like a bit more time to mix and lay out the concrete so it's not so stressful that I end up hurting my back. A retarder would be nice, but I've never heard of anyone "splashing in" a retarder in smaller mixes and I also don't know how easy it would be to get a small amount that would be enough for 700 liters. I've seen different opinions about retarders, though; some say it's just a sugar mixture, and others say that real retarders are significantly more advanced than that (seems reasonable...). My question is, if I don't have a requirement that the concrete must start setting within a certain time, can I reach a good compromise by simply mixing in a few deciliters of sugar per batch (assuming a batch is 50-70 liters or so)? The floor will be self-leveled later, so a troweling machine is not relevant. I'll probably scrub it by hand when it’s firm enough to lay a board on and walk on it.

 

[SBH]

no, do not mix in sugar.

be prepared for an entire day and do not work alone

 

[jeppeknaster]

It works. The concrete expert and concrete pumper "Tyresö," who unfortunately is no longer active on the forum, explains this here
http://mobil.byggahus.se/forum/byggmaterial-byggteknik/160899-gjutning-och-kyla.html

 

[D09]

It works. The concrete expert and concrete pump operator "Tyresö," who unfortunately is no longer active in the forum, explains it here
[link]

Thanks for the link, interesting reading

 

[Mikael_L]

It works. The concrete expert and concrete pumper "Tyresö", who is unfortunately no longer active on the forum, explains it here
[link]

Yes, it almost feels like one of those questionable garage tips.
But after all, since the tip came from "tyresö" I think I trust the truthfulness, as he is really knowledgeable about concrete.


edit: Tyresö was banned not at all due to poor knowledge or bad advice.
If I understood correctly, it was for stealth advertising for himself, attempts that were repeated ...

 

[d_nilsson]

Hi,

Yes, I had read the thread where "Tyresö" says it works before I asked, but then there are others who work with concrete who don't seem to think it's so easy to achieve. Here for example:

http://betong.se/2010/04/vad-hander-om-man-haller-vanligt-socker-respektive-salt-i-betong/

What would be interesting is to hear from someone who has tried this in practice? What Martin Hansson (R&D manager at Sika for concrete additives) responds above is that the effect of regular sugar as a retarder is difficult to control. So what happens if the reaction is too strong?

 

[D09]

Does this apply to flytspackel in that case?

 

[Mikael_L]

Hi,

Yes, I had read the thread where "Tyresö" says it works before I asked, but then there are others who work with concrete who don't seem to think it's so easy to get right. Here for example:

[link]

What would be interesting is to hear from someone who has tried this in practice? What Martin Hansson (R&D manager at Sika for concrete additives) answers above is that the effect of regular sugar as a retarder is difficult to control. So what happens if the reaction becomes too strong?

But he does mention that sugar works as a retarder, just that the effect is a bit hard to regulate. So if you don't mind living with some uncertainty about whether it gives 3 or 15 extra hours, you could probably add that tablespoon of sugar per 100 liters of concrete as Tyresö suggests, I would think.

 

[EinarL]

Planning to pour a floor in the basement, about 7m^2, so about 700 liters of concrete. It's a bit too little to call in a truck with a pump, even though it was really convenient for the larger floors I've already done. I'm considering renting a larger mixer and attempting to mix myself, but I'd like to have a bit more time to mix and lay the concrete so it doesn't get too stressful, potentially causing back strain. A retarder would be nice, but I've never heard of anyone adding retarder to smaller mixes and don't know how easy it would be to get a small amount just for 700 liters. I've seen different opinions about retarders, some say it's just a sugar mix while others claim that real retarders are significantly more advanced than that (which seems reasonable...). My question, however, is if I don't require the concrete to start setting within a certain time, can I achieve a good compromise by simply adding a few deciliters of sugar per batch (assuming a batch is 50-70 liters or so)? .

The Danes reportedly sabotaged German concrete structures during the war by adding sugar during the concrete mixing, thereby reducing the concrete's strength. A few sugar cubes in maybe a couple of hundred kg of concrete were said to suffice. Humus, i.e., soil and biological material, also degrades the quality of the finished concrete. Therefore, adding sugar to the concrete is not recommended.