Concrete curing time question

[strength_and_power]

When pouring a footer into a trench that has been saw cut into an existing slab and will be doweled to the existing, using 4500psi mix with a curing accelerator, 80 degree temps,
What kind of time would be needed for the concrete to cure enough to be able to be drilled for anchor bolts and weight applied?

 

[DougWil]

In 2 weeks you would probably be up to the 3500psi or higher range which is where most mechanical anchors would have reasonable values.

Epoxy anchors require a 28 cure.

 

[readhead]

What Doug said. Look carefully at doweling into the existing slab. The new chunk may perform better on it's own.

 

[wssix99]

Read your instructions for the anchors and lift. They should tell you. 28 days is always a safe bet.

If your repair slab (it isn't a footer and doesn't mechanically work like one) doesn't have any rebar in it, I would definitely wait for 28 days to avoid any potential complications with cracks forming.

 

[ms fowler]

Ask your concrete supplier. He should know the curing time curve for the accelerator he uses. Also check with your lift manufacturer to see what PSI is needed. If 3000 PSI is required and you are using 4500 PSI with an accelerator, you may be good to go in as little as a day or two. Normally concrete reaches its design strength in 28 days, but the curve is not linear. General, w/o accelerator it should be 67% to 75% of the design in 7 days--if there is sufficient water for curing. If you only need 3000 PSI and are using 4500 PSI even w/o accelerator you should be OK in 7 days.
Keep free water on the surface to help cure it.