The question of open pores in aerated concrete and closed pores in foam concrete. Myth or is there a difference in the structure of materials?

In the comments, readers often write that foam concrete differs more favorably from aerated concrete in terms of water absorption characteristics in that it has closed pores. And thus, it absorbs less moisture, and, therefore, will last longer. I propose to understand - is it so? Moreover, I have preserved photographs of chips from aerated concrete blocks.

These are photos of aerated concrete with a density of D500 and D400. The one that is gray is D400. It still has a high percentage of residual moisture (after rains), which is why it has such a color. It dries - it will become much whiter. I will enlarge the images to better see the porous structure of aerated concrete.

D400 has larger pores, which is understandable - its density is less. But if you look closely, the pores are not interconnected (with rare exceptions). Those. more than 95% of the bubbles are closed. What about foam concrete?

The same structure, and the pores have completely different sizes. This is due to the fact that an organic foaming agent is used to form bubbles in foam concrete. Sometimes a protein structure (bovine blood) is used. And for foaming the mass in aerated concrete - aluminum powder. It interacts with lime to release hydrogen. We observe its bubbles in the structure of aerated concrete.

I believe that foam concrete and aerated concrete (at the same density) are approximately equal in terms of the degree of water absorption. The difference may be due to the fact that in foam concrete the material itself is from a sand-cement mixture, and in aerated concrete there is also lime. It is more hygroscopic. It turns out that foam concrete is stronger? No. Aerated concrete is processed in an autoclave - the blocks are heated at high pressure. In this case, an increase in the set of strength occurs (carbonate crystals grow faster, they are larger in size, the material is stronger). Aerated concrete has a higher strength class with the same density of materials. And foam concrete matures in natural conditions.

Even aerated concrete practically does not shrink (it is not more than 1 mm / meter). Foam concrete cracks in masonry (shrinkage up to 3 mm / meter). Therefore, fresh foam concrete masonry cannot be plastered.

Shrinkage cracks in foam concrete walls can be seen in this video: https://youtu.be/lel7p7Vshn8

Photo of the foam concrete extension, taken by me in 2019. Cracks in the plaster are visible, and in some places the plaster falls off due to changes in the size of the blocks. Apparently, the building was plastered immediately after laying.

Someone will say - again I'm drowning for aerated concrete. I could change my mind, but the facts say otherwise. So when choosing: foam concrete or aerated concrete, you need to look at the main characteristics of the materials, and not at the geometry of the pores in them. Moisture absorption is far from the most important characteristic. Nobody is going to arrange a pool inside the masonry.

And if you allow long-term construction, then raise the masonry onto a concrete tape (in the case of a slab foundation), as I did.

The first row was never in the water during the entire construction period. Although, the walls wintered without a roof.