Perfect Aircrete, Kitchen Ingredients [video]
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What's novel in this video is the production method, which uses only a standard cement mixer.
The 'traditional' method is here: https://www.youtube.com/watch?v=tnNua21zx78
It's made differently from this, though. It is aerated through a chemical reaction rather than mechanically.
Lots of people looking for compensation and claiming mis-representation.
It's a very particular use case of a very particular product, not relevant to the wide majority of AAC uses around the world, which is largely non-structural and not reinforced, or subjected to moderate compressive loads, such as lateral walls for 1-2 stories buildings in non-seismic areas.
However as any fule (engineer) kno, reinforced and especially pre-stressed conc members will fail in quite a dramatic fashion. Unless you notice rust dribbling out then you can end up with anything from the roof failing to the roof exploding. I don't think anyone was daft enough to pre-stress these things.
I don't know how much money was saved but it was a really stupid application and basically ended up punting far greater costs due to remediation down the road.
While it might technically be true, that surely does not absolve the engineers who did this crap.
There is a general social expectation that new buildings should be structurally sound for a duration on the order of a century. So, if you deliver something that has a mean time before catastrophic failure around 30 years, you also need to account and set up the institutions that will handle the failure, the same way nuclear companies are required to set aside money for their decommissioning. You need to have periodic inspections for signs of early failure etc. and this whole circus needs to be disclosed and priced into your tender.
In reality, this entire fiasco was a dirty and cheapest way to satisfy the contract, ye old "good enough for government work" as evidenced by the fact no substantial number of private buildings of the same period are having this problem.
The maintenance provision was snuck into - or bribed into - some mountain of legalese, but the fuckers knew exactly that they were putting children in harm's way.
On the other hand, the video linked attributes too much credit and complexity to the foam manufacturing method, it can certainly be done with very primitive technology. Here are some dudes doing it in a developing country, it's very very basic, the foam generator is basically a steel wool sponge where pressurized air combine with water containing the foaming agent. They give out the complete recipe and details of their tools:
When an office building was built in any earthquake-prone area that housed a nuclear engineering consultancy I worked in for several years, multiple test specimens of concrete were poured and kept for later testing and evaluation, and extra ones were kept should there ever be a question about the concrete's quality in the future.
This video makes aircrete with cement + water + thickening/foaming agent, but it doesnt use any sand, no?
The wikipedia pages suggests that this is more prolery referred to as "foam mortar" or "foam cement"
Another method: https://www.youtube.com/watch?v=tnNua21zx78
I had the choice between aircrete and that for my house and went for good ol bricks instead
There are AAC factories in Ukraine, Belarus, Kazakhstan that I know of. The rest are probably too seismically risky to be major AAC markets.
It would be amazing if AAC-like material could be produced on-site economically to create a lighter form of monolithic reinforced concrete construction, like filling a formwork with expanding foam.
Because nobody would want to actually hang heavy things on their wall right??
Cabinets
Shelves
Large mirrors
Pot racks
https://www.buyrigifixonline.co.uk/rmd.pdf
> 43kgf (shear load)
That seems really low for shear. The M8 Rigifix say 245 kgf for 1mm displacement in shear.
Also I slightly misremembered the rating for pull-out - actually in 34 kgf, and they are applying a fairly generous 15% safety factor (i.e. tested ultimate strength was 224 kgf). But still, it sucks that you can't just use a normal wall plug and have to worry about this sort of thing.
That's 0.43 kN which is 430N or ~43kgf. Comparing to the rigifix table they are using a heavier aircrete and a smaller safety factor, which would take fix-v up to 80kg but that's still a big difference. I wonder if there is a testing methodology difference, as usually resin fixings are considered stronger than plug fixings.