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Posted: Sun Apr 15, 2007 8:53 am
by Mikey_C
I recently poured a fairly deep (1M) strip footing using ready mix, a significant quantity of water rose to the top of this footing, I understand this is described as bleed water, (please correct me if I am wrong), this wasn’t a problem for the footing because it was supposed to be level and most of the water stayed inside the restrictions of the formwork and evaporated slowly.

However, I am about to lay a considerable amount (24m³) of ready mix as a base for a block finish and as a finished hard standing area. This will of course have a fall on it, meaning the bleed water will run off, from what I have read this rapid loss of water from the ready mix will cause a reduction in its strength.

Could I canvass your professional and experienced opinion on whether this is a problem? Is this what normally happens? Or what is done to avoid it?

:)

Posted: Sun Apr 15, 2007 9:39 am
by seanandruby
why concrete sub base? there are cheaper alternatives.. crusher run, mot etc; if it needs concrete because of heavy loads then a semi dry ( 25ish slump ) is adequate. For your hard-standing a 50ml slump will suffice. you shouldn't have excess water, so, no need to worry about run off. get it "closed" in with a plastic float then keep your eye on it for finishing.

Posted: Sun Apr 15, 2007 6:25 pm
by Tony McC
If you have excess bleed water, it's probably due to incorrect use of additives, especially plasticisers, and any loss of bleed water should dramatically affect final strength.

In other words - don't worry about it! :)