Tell me - how long can I reasonably expect a C20 or C25 concrete mix to stay pliable enough to work? I hear that adding 0.01% to 0.15% sugar to the mix extends its working life - is this true or is someone just pulling my chain? Does the addition of plastisizer help?
It all depends on ambient temperature, it will not go off as quick in colder temps, the temperature has to be plus 5 and rising to use it without the need of antifreeze mixture, or it has to be covered to stop it freezing. Sugar!!!!!! I think someone's pulling your leg and plastersizer is not generally needed in concrete.
I just looked this up and blow me down with a feather, it is true, SUGAR slows down the setting of concrete, learn something new everyday. http://www.standard.co.uk/news/tran...ent-flood-farce-on-victoria-line-9081168.html
It sets by chemical reaction, even IF it does work you shouldn't do it. Slowing the setting time could damage the concrete.
Got a huge wall to skim tomorrow, might try a bit of salt & pepper in the mix, see if it slows it down
it's just a natural retarder - very very low ratio (less that 0.04?)/weight of cement - I thought everyone knew such useless facts ?
Have you ever ordered readymix and been asked if you want white or brown sugar? There's obviously a reason.
I said learn something new every day, but would I do it, NO, it would work out about 10 bags of sugar per M3.