Steam Curing an Outdoor Pour

[kylesito]

I am in a project that requires the installation of new frames to support a piece of industrial equipment with a 3 day MAX turnaround. This includes demolition of the existing frames and installation of new frames with footings!

I am curious if anyone has experience/knowledge (not always the same thing, btw!) of curing an outdoor pour using steam to get the mix up quickly? I would imagine tents or enclosures can be erected but didn't know if this was practical or not.

Also, beyond type III portland cement and stating a 4,000 psi rating in 3 days, what are other items that generally need specified for High Early Strength Concrete?

 

[SrVaro]

I recently completed a project this year attempting to complete a quick turnaround similar to yours. The contractor stated it could be completed within the schedule even with all the tenting, steaming, and special concrete requirements. Long story short, it turns out he could not. The steam temp needs to be reached gradually and then brough down to ambient gradually so this takes additional time. I would suggest an early telecome with the complete team, contractor, concrete supplier, owener, etc to make sure all are on the "same page". I stated this as a requirement on the drawnigs, and tried to set up, but the they did not follow throught till after the project went south.

But to your main question, the other requirement I placed was no fly ash based on the research I completed. I also requested early breaks at 24, 36, and 48 hours to see if the concrete would make the required strength at 3 days.

Good luck and I would be interested in hearing if your project was a success.

 

[CANPRO]

How big are the footings? Just thinking outside of the box, if they aren't a ridiculous size and there is room to work it, maybe you could have your footings precast and cured before your 3 day window starts. Unlikely that this is practical, but I thought I would throw it out there.

 

[kylesito]

SrVaro, that is interesting that it didn't work out! In my case, there is a pretty intimate relationship between the facility and the contractor. I have pitched the idea to them that we all sit down and talk about this ahead of time and so far they have seemed willing. We will see! I will note the flyash requirement though..thanks.

Caneit, we did talk about doing precast footings. The problem I have with that is making sure there is adequate bearing and levelness of the subgrade to ensure they set correctly. I don't know what methods are there to ensure this happens but my experience has not given me a lot of hope that contractors would go the extra mile to see it was taken care of properly.

 

[ron9876]

If precast is an option you can place the footings in a grout bed. That will give you uniform bearing and the grout could easily reach the needed strength.

 

[MiketheEngineer]

As we speak - Missouri DOT is currently replacing large sections of a bridge deck (Stl - I-64) and re-pouring immediately. They are allowing car traffic the next day.

I have NO idea what this stuff is - but it seems to work and I bet it is expensive. But might solve your problem if you can find out the particulars.

 

[kylesito]

The reading I have done is that a mix called 4x4 is what DOT's use. To my knowledge, yes, it is expensive but it can get 4,000psi in 4 hours. I am not familiar at all with it, but just the reading I have done.

Ron, have you worked with the grout bed idea personally? What are the specs on the grout? I would assume you want something liquid enough to allow the foundation to get worked in level but stiff enough to not let it run everywhere. If that could work, that could allow the precast option to happen as there is room available nearby to stage everything.

PE, SE
Eastern United States

"If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death!"

 

[CANPRO]

Its actually 400 psi in 4 hours...4000 psi in 4 hours would be insane

http://www.basf-admixtures.com/en/products/4x4_concrete/Pages/default.aspx

 

[ron9876]

I have worked with the grout option a few times before. The grout needs to have the necessary strength and needs to be flowable.

 

[kylesito]

Haha...yes, 4000 is probably unrealistic!

Thanks for the feedback.



PE, SE
Eastern United States

"If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death!"

 

[hokie66]

When I read the OP, I thought is was the frames as well as the footing that had to reach strength. So I thought...Steel? Precast? Design the shoring to stay in place until the cast in place concrete reaches strength?

If it is only the footings, just use 10000 psi concrete and be done with it.