"Just going to see O'Reilly, dear!"
Posted on 09/02/2023 2:55:29 PM PDT by RandFan
With just days to go before the start of the new school year, more than 100 schools in England have been told to shut buildings made with a certain type of concrete unless they put in place safety measures.
Here is what we know so far about the material at the centre of all this.
What is RAAC?
Reinforced autoclaved aerated concrete (RAAC) is a lightweight material that was used in roofs, floors and walls between the 1950s and 1990s, mostly on one and two-storey buildings.
It is a cheaper alternative to standard concrete. It is quicker to produce, and easier to install.
It is aerated, or "bubbly", like an Aero chocolate bar.
But it is less durable and has a limited lifespan of around 30 years.
Its structural behaviour differs significantly from traditional reinforced concrete.
Moreover, it is susceptible to structural failure when exposed to moisture. The bubbles can allow water to enter the material.
If that happens, any rebar reinforcing RAAC can also decay, rust and weaken.
Because of this, RAAC is often coated with another material, such as bitumen on roofing panels. But this material can also degrade.
The Standing Committee on Structural Safety (SCOSS) noted that: "Although called 'concrete', RAAC is very different from traditional concrete and, because of the way in which it was made, much weaker."
According to Loughborough University, there are tens of thousands of these structural panels already in use and "many are showing signs of wear and tear and deterioration".
The Health and Safety Executive says RAAC is now beyond its lifespan and may "collapse with little or no notice".
(Excerpt) Read more at bbc.co.uk ...
This is really bad and a new crisis/scandal. Hospitals, schools, courts, etc are not deemed safe!
Seems like a dumb idea to use that material in rainy Britain.
It inevitably happens when a country goes socialist. Those in charge start to take as much as they can for themselves at the expense of the country itself.
"Just going to see O'Reilly, dear!"
In the UK civilization itself is literally crumbling and in more ways than one. I’m eligible for a UK passport but I say why bother I wouldn’t want to live there anyway.
Oh boy, a new crisis!
Sorry, Brits need to send money to Ukraine.
Buildings falling apart is just part and parcel of living in a global country…
“Anyone in construction here?”
Yep, with concrete we require at least 1” of concrete FULLY surrounding rebar so as to prevent water from reaching the rebar and thereby (of course) causing the rebar to rust. Rebar gives concrete its tensile strength (concrete has excellent compressive strength without rebar), so take away the rebar, and any tension (pulling) on the concrete and it will fail.
At least that was the case when I managed major construction projects many years ago - cannot see why it would be different now.
I have NO CLUE as to why this crap was permitted in the UK, other than they may have had a Labor government at the time.
..light weight air entrained concrete .. they got what they paid for. Probably lasted longer then called for.
Probably because it was cheaper.
In a climate such as in England, why would you use such material?
“Public buildings are literally CRUMBLING in the UK in new crisis”
_______________________
Don’t say that to loud or our congressional “leaders” will propose the U.S. rebuilding the U.K.
“Thanks for that. Just reading this article/explainer:”
Thanks for the link, what a MESS! The thing about water reaching rebar is that it will wick-along the rebar and damage a good length of it, even if only its end is exposed. It’s CRAZY to use a porous concrete with rebar!
By the way, the Roman Pantheon is nearly 2000 years old and was made with concrete that actually self-heals and no rebar (but then it starts at 6 feet thick). We’re still trying to figure out the recipe for their concrete!
I’m going to experiment mixing dirt with cement for walkways and don’t care if there is any organic matter in it.
My goal is simply to prevent weeds.
I worked with laying foundations and walls. You work to vibrate the air OUT of concrete, not put bubbles into it.
Tofu Dreg construction practices of the UK, apparently.
In their defense, England was supposed to be covered by glaciers by the 90s. The buildings weren’t expected to last this long.
We know how to make Roman concrete now. Long ago someone had the presence of mind to chip the recipe onto a stone and about 20 years or so someone found it. If I remember correctly the two magic ingredients are salt water and volcanic Ashe. It does have a different texture- sort of like wet clay.
Except now and for the last 100 years, it has set big time for the Brits.
Consider a few other humanity greats like...
- Rome
- Dutch
- Spanish
Anybody want to guess who's next?
Hint: Civilization power tends to migrate from east to west.
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