When can the formwork be removed after the concrete has been poured. A few examples from personal experience

During construction, I kneaded by hand and took from mixers (factory concrete) more than a dozen cubic meters. There was an article about the very formulation of self-weight concrete here

As a rule, concrete is poured into the formwork. When erecting the walls, I used a fixed formwork made of aerated concrete. But this is not the point now. Question: when can the formwork be removed from structural units? It all depends on the type of node and temperature conditions.

If this is a structure in the form of a foundation supported on the ground, then you do not need to wait for the normative set of concrete strength. The main task is to prevent chips and destruction in the body and on the surface of the concrete when removing the formwork.

When pouring concrete tape for the fence, I had a limited volume of planks. I installed shields for 2-3 spans, filled them in and moved them to the next section along the fence. So he filled in almost 120 m of tape. Of course, I didn’t wait for the concrete to gain the grade strength. He carefully removed the formwork on the third, sometimes on the second day. M200-250 concrete. Then watered the tape for 1-2 days with water.

He took out the type-setting blocks and lining for the fence from the forms in a day. Concrete matured in a greenhouse workshop, in which in summer, on a clear day, there was a heat up to +50 gr. The blocks were made using the "washed concrete" technology. And a time delay for two days would lead to a gain in strength of the surface layer of concrete. In other words, the blocks simply would not be washed (the concrete layer would not be washed off and the pebble would not be exposed).

During the construction of the house, I removed the formwork from the armopoyas on the third day. He also poured water on it for three days. Factory concrete grade was M250 (compressive strength B20). It was poured in the summer, so nothing crumbled and, moreover, did not break off. Such a haste was needed in order to have time to lay out the second floor before frost and snow. But in 2020 I didn’t manage to do it.

I removed the formwork from the terrace after three days. M300 grade concrete.

A concrete tape or armored belt is one thing, and a monolithic floor or beams are another. In these cases, you need to know the norms of concrete ripening to brand strength.

When pouring monolithic lintels from insulated fixed formwork, I did not remove the horizontal supports under them for about a month. At summer temperatures + 20-25 gr. concrete gains brand strength for at least 28 days.

The formwork from the often ribbed slab, made using the MARKO-economy technology (or the Homeowner), took off after 28 days. M300 concrete also matured in July.

He began to remove the formwork from the monolithic staircase 42 days later. M300 concrete. But it was gaining strength in temperature conditions not higher than +10 degrees. it was already November (the temperature was positive in the house). Therefore, it was too early to remove the formwork even after a month.

There will be a separate video and article about the construction of a monolithic staircase. Anyone interested - subscribe or drop by here.

The strength gain of concrete depending on temperature can be classified in this table:

It can be seen from it that the lower the temperature, the slower the concrete gains strength. The physicochemical process of crystal growth in concrete slows down. This must be taken into account in the summer, do not remove the formwork earlier than 28 days in critical loaded structures. And if it is colder, about zero, then it will take two months for the standard set of concrete strength.