Will concrete set under water?

[ruby rocket]

I'm building an inspection pit and its flooding from a slow spring in the bedrock, if i mass pour the pit with concrete will it go off under water?

[Carberry]

How slow a leak? How much water is there already in the hole? How much concrete is needed to fill it in?

Chances are your best solution will be to just pour the mix in more dry than usual, if it is going to be completely submerged though then that is a different story.

[GB_Groundworks]

it will set under water and the nationals readymix will have additives for it but be very expensive, normal crete will set jus try to divert the water with a trench, pump etc

inspection pit for vehicles? or drain inspection pit? yeah it'll be ok, we have one in our workshop but include a sump in one corner for a pump as it will fill with water,

then it'll be ok

[Brucieboy]

As said above, if possible, try to divert/pump out the water before/during concreting. If concrete is poured directly into deep standing water you risk turbulence washing out some/all of the cement/fines. Deep, flowing water is worse. The concrete will displace the water and it will harden eventually but you'll not be 100% certain you've got the correct distribution of materials throughout it's depth. If the water is fairly shallow (say 50mm) with minimal flow and the slab is quite thick (say 200mm) it's not so critical. A strongish mix at low-medium workability would be beneficial. However, where possible, get rid of the water before/during concreting.

When we supply ready mixed concrete for deep (many metres) underwater structures, the mix normally contains a special admixture (a thickener similar to wallpaper paste) with a high cement content (about 400 kg/m3). It's supplied at quite a high slump (workability) and tremied into place (poured down a tube the entire depth) to prevent washout - never freefall.

[Chaunceytoth]

All concrete will set up under water.Take test cylinders let them get harden so that cylinder casing is removed. It is then put in water to cure for a period of time before breaking them.

(Edited by Tony McC to remove unwarranted spam links. Do it again, sunshine, and I'll bite yer knackers off!)



Edited By Tony McC on 1328551142

[lutonlagerlout]

weird kind of spam from mr toth,shall we monitor him?
LLL ???

[Carberry]

Delete and ban. Seems the bots are getting better though.

[seanandruby]

why? It is right, albeit on structural concrete, to make test cubes, strike them and place them in water to cure before sending to the lab' for crushing. Water thermostatically controlled. We concret under water a lot but pump it out as you chase the water along, pushing it with the concrete. I've laid concrete and salt glaze pipes under water. You wouldn't want to try breaking them out. We waterproof our preformed, reinforced manhole bases first.

[London Stone Paving]

weird kind of spam from mr toth,shall we monitor him?
LLL ???

If it happens again we'll look into it ???

[lutonlagerlout]

its the fact he has a link in his sig and also a moody link in the post
very bot like
i am deleting around 50 people every week that register with moody russian type names but they still slip through
LLL

[seanandruby]

i see now. press the button then and zap him :laugh:

[ruby rocket]

Many thanks guys, sorry for slow reply i moved house and only now set up internet at the new address