Limited curing time question 1

[struct_eeyore]

Currently designing a small 6' retaining wall. Contractor is requesting we allow him to pour the stem after 3 days. I've never seen any work done before the 7 day mark, and have not been able to locate anything in ACI or IBC regarding this - so hoping someone might point me in the right direction. Now, the stem comes out to about 88 lbs/ft on a 4'Wx1'D footer, and intuitively, having a guy stand on the footer ever 2 feet does not seem like a problem - at 3 days - (obviously back-fill will not be in). What are your thoughts?

 

[Agent666]

I can't imagine this would be an issue if the footing is reinforced. If you think it is an issue, find out the strength at 3 days and do a check.

 

[SlideRuleEra]

Currently designing a small 6' retaining wall. Contractor is requesting we allow him to pour the stem after 3 days.

A reasonable request by the Contractor. For extra insurance, consider having him use an accelerating admixture in the concrete (at his expense).

Concrete poured in soil (footing) has near optimal curing conditions. After the stem is placed, have the Contractor resume (wet) curing of the footing (in addition to curing the stem).

http://www.SlideRuleEra.net

 

[Gerber_EIT]

structee:

Per ACI 301-10 section 5.3.6.1: "Unless otherwise specified or permitted, cure concrete in accordance with 5.3.6.2 or 5.3.6.3 for at least 7 days after placement. Unless otherwise specified, cure high-early-strength concrete for at least 3 days after placement." Take a look at ACI 301 for some of the other requirements. Personally, I wouldn't allow it unless the contractor was going to provide some type of curing compound.

 

[dauwerda]

I don't see any issues with this. What is the worst thing that will (realistically) happen? Forms and/or tools dropped on the footing surface - more likely to to cause some localized spalling due to lower strength concrete - not likely to be structurally detrimental to the performance of the footing.

 

[skeletron]

I've sweated over this in the past and I think the stress was a little unnecessary.

Ideally the contractor should wait until 7 days. There is better established strength and usually a 7 day break also occurs to verify the concrete is adequate.

If the contractor wants to accelerate the schedule get them to:
A. Use high early strength cement
B. Test at 3 days
C. Make sure there are dowels

The only things I would be concerned with is how they want to form off the footing and making sure they have proper curing. Sometimes they think sticking an expansion anchor or adhesive anchor is fine, but it's really too early for that kind of stuff IMO. And sometimes they want to accelerate to get off the site.

 

[Lomarandil]

Yeah, I'd allow it.

----
just call me Lo.

 

[Tomfh]

I’d allow it provided it exceeds say 15MPa/2000psi

 

[Ron]

Agree with SRE....reasonable request by the contractor. Initially, the only load that will be on the footing is the dead load of the masonry. It will take a couple of days to build the wall to six feet....all the time the footing concrete is gaining strength. Curing should be continued even after starting to place masonry...just don't wash out the mortar! A fine fog mist is best.

In short, not a problem.

 

[dauwerda]

Ron, initial post said pour the stem. I believe it is cast in place, not masonry.

 

[Ron]

dauwerda...oops! You are correct. Should have read closer.

However, the load is still very small considering the size of the FOOTING (not footer, structee)