how many days will it be ready to put new concrete ontop of first poured concrete structure?

Question

for example a newly concreted foundation slab, when it will be ready to pour the next concreting, columns or beams on top of it?

Answer 1

luckily, it usually takes longer to set up the rebar and formwork for the columns, than it takes for the mix to reach compressive strength to pour again...

columns tend to have blockouts in the slab, so you are not pouring on the slab
if this is residential, or lightly loaded commercial, a mono-poured slab may have been the design

most mix designs are set to reach a certain compressive strength in a certain amount of days..

depending on your area and the weather, you may have a 3 day or a 7 day mix...you have to check what was specified

tests and other methods are only required for concrete of 2500 or higher, so if you have a lower design, there arent the required tests.
the supplier would have used a predesigned mix that they have tested and it is a sure bet...

check what they supplied...

Answer 2

This is very dependent on the concrete mix design and the minimum compressive strength required for the project. Concrete with a standard Type 1 Cement will gain 90% of its strength in 7 days. But if you are using Type 3, High Early, Cement, you could pour the next day. Just depends on the specifications for the project.

Typically, specifications will require 80% of design compressive strength which would allow sequential pours after 3 days with a common type I concrete mix with a compressive strength in the range of 3000-4500 psi. The compressive strength can be checked with early-break cylinders or a Swiss Hammer.

Answer 3

It really depends on the load you will be putting on the new concrete when you pour the columns or beams.

You usually get 2/3 of the design strength in 7 days and full design strength in 28 days. Please note that I said "design" strength not the ultimate strength.

If you use high early strength concrete, these numbers are reduced.

Answer 4

It depend on teparatue . For normal temperature it is minimum 12 hours as in 24 hours concrete gets 50% strength of total. In cold season working condition depends upon its stenght.

Answer 5

depends on the temperature and humidity really-is it very cold where you are...usually three days is the waiting period before it can pass to pour more concrete..but if it is cold or rainy there then maybe a week or two.

Answer 6

well, 24 hrs is safe to walk on, 48 is enough to build on, but id be safe and say 72-96 before pouring more on top,