How long must concrete slab cure before anchoring equipment?

In summary: You can do the same with a slab, you'll get a lot more strength faster than you would just waiting for it to gain strength at ambient temperatures. 5,000 psi should be no problem for a wedge anchor. Just make sure you don't over torque the bolts. The concrete will only have so much compressive strength. If you over torque the bolt it will cause the concrete to blow out around the bolt. You may want to consider using a epoxy anchor adhesive. They are commonly used in concrete and have a high strength. If you heat the poured concrete to 120 degrees F for one day you can get 75% of the ultimate strength. Keep it wet and make sure you don
  • #1
Dorin
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We cut the concrete flooring in our plant for some plumbing work and will soon re-pour a slab of 5,000 PSI "High-early" concrete. In order to minimize down-time we need to re-install equipment by drilling/anchoring into new concrete as soon as the curing has yielded sufficient strength. The equipment would be anchored using 1/2"X3" stainless steel wedge anchors and weighs cca 500#'s. It rests on 4 3"x3" feet forming a cca 5' square. Will two days of curing allow for sufficient strength to drill and compress wedge anchors without causing the new concrete to break under the tension?
 
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  • #2
Dorin said:
We cut the concrete flooring in our plant for some plumbing work and will soon re-pour a slab of 5,000 PSI "High-early" concrete. In order to minimize down-time we need to re-install equipment by drilling/anchoring into new concrete as soon as the curing has yielded sufficient strength. The equipment would be anchored using 1/2"X3" stainless steel wedge anchors and weighs cca 500#'s. It rests on 4 3"x3" feet forming a cca 5' square. Will two days of curing allow for sufficient strength to drill and compress wedge anchors without causing the new concrete to break under the tension?

Who is doing the pouring? It would seem that is a question for their managers and consulting engineers...
 
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  • #3
You're not wrong in saying that's a question to be answered by managers and consulting engineers. Posing the question here is a little more handy at the moment.
 
  • #4
Dorin said:
You're not wrong in saying that's a question to be answered by managers and consulting engineers. Posing the question here is a little more handy at the moment.

But what if we give you bad advice, and the floor cracks? Who loses their job? :-)
 
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  • #5
berkeman said:
But what if we give you bad advice, and the floor cracks? Who loses their job? :)

I'm not looking for anyone's stamped recommendation which I can bring to court to hold them liable; simply looking for a rough estimate and some generic advice based on experience.
 
  • #6
Put it this way --- not even tract housing developers start bolting down mudsills at two days.
 
  • #7
Bystander said:
Put it this way --- not even tract housing developers start bolting down mudsills at two days.

Fair enough, but they don't leak $10K/hour during down-time.
 
  • #8
Dorin said:
they don't leak $10K/hour during down-time.
:rolleyes:Depends on which set of books you audit.
 
  • #9
Dorin said:
Fair enough, but they don't leak $10K/hour during down-time.

as Bystander said, depends on what side you sit

consider how many $10's of 1000's its going to cost if the concrete is used too soon and the whole system fails and needs to be redone
wasting even more time and materials that all = lots more moneyD
 
  • #10
Dorin said:
We cut the concrete flooring in our plant for some plumbing work and will soon re-pour a slab of 5,000 PSI "High-early" concrete
Did you not have a timeline of work progression made at the outset? Especially with your downtime cost. How do you know you are on schedule and within your budget?
 
  • #11
Dorin said:
simply looking for a rough estimate and some generic advice based on experience.

You got that advice - ask the project engineers.

It sounds like you are looking for a reason it's OK to use a shorter duration. I don't think you're going to find that.
 
  • #12
Dorin said:
We cut the concrete flooring in our plant for some plumbing work and will soon re-pour a slab of 5,000 PSI "High-early" concrete. In order to minimize down-time we need to re-install equipment by drilling/anchoring into new concrete as soon as the curing has yielded sufficient strength. The equipment would be anchored using 1/2"X3" stainless steel wedge anchors and weighs cca 500#'s. It rests on 4 3"x3" feet forming a cca 5' square. Will two days of curing allow for sufficient strength to drill and compress wedge anchors without causing the new concrete to break under the tension?

The people who sell the concrete should have a table that shows compressive strength verses cure time and importantly verses temperature. Time and temperature and moisture effect cure. Keep it warm and moist. The amount of money lost because of down time would pay for an engineer. To what extent, if any does the equipment vibrate?

http://www.sakrete.com/uploads/downloads/Sakrete%20Fast%20Setting%20Concrete%20Mix%20TDS.pdf
 
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  • #13
Talk to the company supplying the concrete. Beware that wedge anchors don't seal the hole so if you wash the floor it's possible to get water sitting in the hole causing the anchor to corrode. Some people favour resin or cast in anchors for that reason.
 
  • #14
If you heat the poured concrete to 120 degrees F for one day you can get 75% of the ultimate strength. Keep it wet and make sure you don't exceed 180 degrees or this will cause unsound concrete at later dates. This is how precast manufactures increase production, they accelerate strength development with heating so that they can strip molds sooner to refill.
 

Related to How long must concrete slab cure before anchoring equipment?

1. How long does concrete take to cure before anchoring equipment?

The curing time for concrete before anchoring equipment can vary depending on several factors such as temperature, humidity, and the type of concrete mix used. In general, it is recommended to wait at least 7 days for the concrete to cure before anchoring equipment.

2. Can I anchor equipment on freshly poured concrete?

No, it is not recommended to anchor equipment on freshly poured concrete. The concrete needs time to cure and gain strength before any heavy loads can be placed on it. Anchoring equipment too soon can cause the concrete to crack or fail, compromising the stability of the equipment.

3. Does the curing time differ for different types of concrete?

Yes, the curing time can differ for different types of concrete. For example, fast-setting concrete can cure in as little as 24 hours, while regular concrete may take 28 days to fully cure. It is important to follow the manufacturer's instructions for the specific type of concrete being used.

4. What happens if I anchor equipment too soon?

If equipment is anchored too soon, before the concrete has had time to cure and gain sufficient strength, it can cause the concrete to crack or fail. This can lead to safety hazards and costly repairs. It is important to wait for the recommended curing time before anchoring equipment.

5. Can I speed up the curing process?

Yes, there are ways to speed up the curing process, such as using accelerants in the concrete mix or applying heat to the concrete. However, it is important to consult with a professional before attempting to speed up the curing process, as it can affect the overall strength and durability of the concrete.

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