Stay-in-place formwork is made as easy as erecting steel stud walls, and covering them with high grade MgO drywall of sufficient thickness and density (1.5cm D1.1). Chinese suppliers have plenty of that prefabricated with fitures. https://s.1688.com/company/company_search.htm?keywords=%C4%A...
One important thing: always ask for MgO board with MgSO4 binder. MgClOn ones can turn corrosive due to minute manufacturing procedure deviations.
2. You mix bubble generating chemical into concrete that will expand it after the pour.
It is a tricky and rather obscure tech mostly used across the former bloc countries or places that used to receive Soviet tech like India. Working with it is much more of a skill rather than science, and this hampers its adoption.
Biggest roadblocks other than skill intensity:
1. Corrosion protection - porous concrete is obviously more permeable than solid one. Easy ways to protect armature do not work as with solid concrete. Zinc anodized steel or other consumable protections will simply be consumed much earlier than in solid concrete, or worse, be eaten by lower PH of a foam concrete after settling. You have to put additional alkalinisers, or flyash, but they can destroy the foam. Finding a foam that will stand your alkaliniser, or a particular composition of flyash (flyash from different powerplants and blast furnaces can be dramatically different chemically and change in composition over time!) is always a challenge.
2. Faster hardening, especially with alkalinisers or geopolymer base - 40 MPa in just 2 days. You also have to spray formwork with water copiously to prevent it from premature drying.
3. Bigger sensitivity to chemical purity of components in general. Additives for foam concrete are an esoteric matter.
What I say about it: advantages worth the trouble
1. You can go down in density down to 350 per cube, or even 150 if you are a concrete chemistry magician. 350 gives you 0.1 W/mK thermal conductivity
2. Incomparably more flowable and pumpable.
3. You can use cements that are wholly geopolymer based or natural cements which is a huge economic incentive.
4. Can be used structurally above 600 per cube density with 13kg/cm2 load bearing capacity. Load bearing capacity goes up non-linearly. 850/cube already give you 30kg/cm2
5. Settled foam concrete is workable with just saws and hand tools. If you have to fix a screw up, it is much easier than with solid Portland cement.
One important thing: always ask for MgO board with MgSO4 binder. MgClOn ones can turn corrosive due to minute manufacturing procedure deviations.
Foamed concrete:
https://en.wikipedia.org/wiki/Foam_concrete
Made in two ways:
1. You mix polymer or protein foam into concrete.
2. You mix bubble generating chemical into concrete that will expand it after the pour.
It is a tricky and rather obscure tech mostly used across the former bloc countries or places that used to receive Soviet tech like India. Working with it is much more of a skill rather than science, and this hampers its adoption.
Biggest roadblocks other than skill intensity:
1. Corrosion protection - porous concrete is obviously more permeable than solid one. Easy ways to protect armature do not work as with solid concrete. Zinc anodized steel or other consumable protections will simply be consumed much earlier than in solid concrete, or worse, be eaten by lower PH of a foam concrete after settling. You have to put additional alkalinisers, or flyash, but they can destroy the foam. Finding a foam that will stand your alkaliniser, or a particular composition of flyash (flyash from different powerplants and blast furnaces can be dramatically different chemically and change in composition over time!) is always a challenge.
2. Faster hardening, especially with alkalinisers or geopolymer base - 40 MPa in just 2 days. You also have to spray formwork with water copiously to prevent it from premature drying.
3. Bigger sensitivity to chemical purity of components in general. Additives for foam concrete are an esoteric matter.
What I say about it: advantages worth the trouble
1. You can go down in density down to 350 per cube, or even 150 if you are a concrete chemistry magician. 350 gives you 0.1 W/mK thermal conductivity
2. Incomparably more flowable and pumpable.
3. You can use cements that are wholly geopolymer based or natural cements which is a huge economic incentive.
4. Can be used structurally above 600 per cube density with 13kg/cm2 load bearing capacity. Load bearing capacity goes up non-linearly. 850/cube already give you 30kg/cm2
5. Settled foam concrete is workable with just saws and hand tools. If you have to fix a screw up, it is much easier than with solid Portland cement.
6. Works like magic with stay-in-place formwork.