Aerated Concrete problems

[ebikeerwidnes]

Hi all
Thought this would be better here because it might well get political

at least it will if I post and I am starting it so.....


Anyway - as a retired teacher my immediate thought was that some Heads will tell affected kids to got to remote learning as in the pandemic

People might think Oh - OK - teachers are already set up for this
and - technically they are - mostly

But due to changes in exam requirements, National Curriculum and requirements from management - I pretty much never taught the same thing 2 years running
bit would carry over but summer required a lot of preparation

so changing to "on-line" would requires a lot of work - and school starts Tuesday or Wednesday next week!!!

basically - if I was married with kids "Hello darling - you know I said I would come with you and help getting the kids uniforms sorted this weekend
well tought - I'm working - in fact you need to feed me and look after the kids all weekend
and don;t forget to contact your boss and tell him you need extra time off as our kids will be at home for a few extra weeks and I will be locked in the study teaching my pupils on-line

what could be a problem in that?



But - it is an emergency so these things happen

except that this concrete is KNOWN (and has always been known) to have a lifespan of about 30 years
and was generally used in the 1950s to 1990s
and has not been replaced - and how long ago was all that

and anyway - 30 year lifespan and you use it in a building?????

Still - even I can;t manage to blame Cameron and Austerity for this - although I would bet the problem was raised and dismissed (zero evidence but ....)

but apparently it was raised 5 years ago - and dismissed - so I can blame this lot - probably johnson and whatever education minister was currently stuck in the revolving door!

 

[BoldonLad]

I remember reading about this problem months ago, in PE I think. I can only assume it was known to the relevant authorities long before that.

It may well be a legacy not actually down to the current incumbents, but, they (Government and relevant Civil Servants) cannot pretend it was a surprise.

Waiting until a few days before schools reconvene, to make this announcement, was an act of lunacy. But, will heads roll, will anyone be given a ticking off?, I wouldn't bet on it.

 

[Rusty Nails]

Apropos of nothing in particular, my first ever summer job in the 60s was working on a Wimpey building site where one of my tasks was taking samples of newly mixed concrete throughout the site every day, putting them into small metal cubes and tamping them down a set amount of times before sending them to the lab for strength testing once they had set. I assume this is not done so thoroughly with aerated concrete.

 

[AndyRM]

I was listening to a report about this on 5Live earlier, and they had someone on on saying that this concern had been raised since 2018 or earlier and the costs could run into the hundreds of millions with no particular deadline on sight.

There was also a government official on saying they were taking a cautious approach, which seems a bit bonkers.

 

[BoldonLad]

Apropos of nothing in particular, my first ever summer job in the 60s was working on a Wimpey building site where one of my tasks was taking samples of newly mixed concrete throughout the site every day, putting them into small metal cubes and tamping them down a set amount of times before sending them to the lab for strength testing once they had set. I assume this is not done so thoroughly with aerated concrete.

As I understand it, the product (Aerated Concrete or RAACS) was not intended/expected to last more than a certain time (cannot recall the exact figure, but 25-30 years, possibly?), so, it is not necessarily a quality assurance problem as a design life problem,

Lack of, or, inadequate maintenance ( a speciality in many public sector buildings) is an added aggravating factor.

The product was, apparently, widely used in the 1950s, 60s, and 70s, so, long overdue for 'problems'. It is not a UK specific problem, the product was widely used throughout mainland Europe.

The above is my in-expert understanding from reading PE.

https://www.concrete.org.uk/fingertips-nuggets.asp?cmd=display&id=1068

 

[The Crofted Crest]

Our neighbours have just had new foundations laid using RAAC!

 

[Beebo]

Our neighbours have just had new foundations laid using RAAC!

I think the main problem is when it is laid horizontally with nothing to support it, such as large ceiling spans.
As it can sag over time.
Foundation won’t tend to have that problem.

 

[Mr Celine]

Our neighbours have just had new foundations laid using RAAC!

How do you autoclave a foundation trench?

 

[The Crofted Crest]

How do you autoclave a foundation trench?

Search me.

 

[Mr Celine]

Apropos of nothing in particular, my first ever summer job in the 60s was working on a Wimpey building site where one of my tasks was taking samples of newly mixed concrete throughout the site every day, putting them into small metal cubes and tamping them down a set amount of times before sending them to the lab for strength testing once they had set. I assume this is not done so thoroughly with aerated concrete.

I did the first two years of a civil engineering degree. Most of first year that I remember was crushing said cubes in a huge concrete cube crushing machine.

RAAC does not contain any cement. No point crushing it as its strength is minimal.

 

[Mr Celine]

I very much doubt it's RAAC. There are ways of aerating conventional cement containing concrete.

Concrete made with cement sets and then hardens over time and should achieve its design strength after 4 weeks. RAAC was made in pre cast panels which harden when heated.

 

[newfhouse]

View: https://twitter.com/michaeltakemp/status/1698592123287642535?s=61&t=IaNHN0MzKohAo3Ktl0DsFQ

 

[Fab Foodie]

It's a modern-day clusterfark - no doubt.
Schools it seems are just the thin edge of the wedge, other public buildings, Hospitals, Universities, private dwellings, etc - who know where it will end?
Then the hunt for who's responsible in various circumstances (am not holding my hopes-out for that one)
Then it's the cost of correction/alternatives and all the interim collateral costs - am certain insurance companies will have a get-out-of -jail card, so it'll be the good old taxpayer again....

After the cladding fark-ups and lack of accountability with that/lack of compensation and remedial actions - am not hopeful here.

 

[matticus]

Telegraph:

Ministers knew about dodgy concrete in schools – but did nothing
… and the rot started with Michael Gove in 2010 when he scrapped Labour’s schools rebuilding programme, writes shadow education secretary Bridget Phillipson

 

[newfhouse]

https://news.sky.com/story/educatio...g-a-fing-good-job-on-concrete-crisis-12954940

I wonder who she thinks “sat on their ärses”.