Curing concrete by flooding with water - how long after placement? 1

[structeng1985]

Hello,

I have a question regarding how long after a concrete placement it is acceptable to flood the concrete to cure it? I believe that as soon as finishing operations are complete, the concrete may be flooded to allow curing, provided that the flooding is static and not a flowing water.

Does anyone have an opinion or experience with this?

Thank you.

 

[RabitPete]

Yes, per ACI as soon as finishing operations are complete, which assumes surface is strong enough to hold the finisher and footprints are leaving no more than 1/8" deep indents. I remember seeing a diagram somewhere showing that you must moist cure for 7 days in order to reach 100% strength at day 28. And if left in air, you will get 60% only.

Honestly, I am doubting if it makes that much difference outside of the lab. On several occasions guys forgot to cure test cylinders and left them exposed to air and still tested a little over the design strength. Looks like most ready mix plants around here overdesign their mixes instead of relying on contractors to proper cure it. Wet cured cylinders (7 days) typically test 20-25% higher than specified mix strength on day 28.

 

[BAretired]

Check the internet. Here's one sample.

https://www.giatecscientific.com/ed...asuring-the-compressive-strength-of-concrete/

BA

 

[dik]

Thanks Bart... good link with the added comment that moist curing with heat... aka steam curing used in the precast industry and that forms should be loosened as soon as the concrete is hard enough, if they are left in place, otherwise they can become 'glued' to the concrete and damaged when removed.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[HTURKAK]

https://www.concretenetwork.com/curing-concrete/

ACI 308R-01: Guide to Curing Concrete providing excellent information for curing of the concrete depending on the environmental conditions, temperature, evaporation rate etc..

 

[BridgeSmith]

Mostly it depends on what the finish has to look like. Concrete can be poured and cured underwater, and it cures fine. The finish looks like crap, of course. If it has to be finished a certain way, the surface has to be solid enough that the water movement doesn't move the paste around and get mixed in.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[dik]

The link posted states the time for walking on the surface. I take exception to "24 to 48 hours - after inital set, forms can be removed and people can walk on the surface". Sawcutting should be commenced 6 to 8 hours after initial set, or earlier.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik