How long must concrete slab cure before anchoring equipment?

  • Context: Undergrad 
  • Thread starter Thread starter Dorin
  • Start date Start date
  • Tags Tags
    Concrete Equipment
Click For Summary
SUMMARY

The discussion centers on the curing time required for a 5,000 PSI "High-early" concrete slab before anchoring equipment using 1/2"X3" stainless steel wedge anchors. Participants emphasize that two days of curing is insufficient for achieving the necessary compressive strength to safely install equipment weighing approximately 500 pounds. Recommendations include consulting with project engineers and concrete suppliers for specific strength tables and considering heating the concrete to 120 degrees Fahrenheit to accelerate strength development. The consensus is that rushing the process could lead to costly failures.

PREREQUISITES
  • Understanding of concrete curing processes and compressive strength
  • Familiarity with anchoring techniques using wedge anchors
  • Knowledge of high-early strength concrete properties
  • Basic principles of construction project management
NEXT STEPS
  • Research the effects of temperature and moisture on concrete curing
  • Learn about the compressive strength development of 5,000 PSI concrete over time
  • Investigate alternative anchoring methods, such as resin or cast-in anchors
  • Consult the Sakrete Fast Setting Concrete Mix Technical Data Sheet for detailed guidelines
USEFUL FOR

This discussion is beneficial for construction project managers, civil engineers, and contractors involved in concrete work and equipment installation, particularly those managing tight timelines and minimizing downtime costs.

Dorin
Messages
7
Reaction score
0
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?
 
Physics news on Phys.org
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...
 
  • Like
Likes   Reactions: billy_joule
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.
 
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? :-)
 
  • Like
Likes   Reactions: Bystander
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.
 
Put it this way --- not even tract housing developers start bolting down mudsills at two days.
 
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.
 
Dorin said:
they don't leak $10K/hour during down-time.
:rolleyes:Depends on which set of books you audit.
 
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
 
Last edited by a moderator:
  • #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.