Concrete Cancer

[Teletran]

what exactly is this concrete cancer anyway

[Mark]

Not entirely sure. I think the best analogy would be that concrete cancer is the same to concrete as rust is to metal.

I know somebody once told me that conrete only had a certain lifespan (old concrete anyway), and I think this has something to do with it.

[ironageman]

I had it in mind that it was something to do with the concrete reacting with the reinforcing, but apparently not - there was something in the paper about it recently and evidently it's caused by too high an alkaline content in the cement, which makes the concrete crack.  Of course, water gets in and the reinforcing then corrodes and smashes the concrete from the inside.  It's been in the news as a lot of new concrete structures in the south-west of England will be affected by it through an error at a large cement works.  They're monitoring all sorts of structures in the region for concrete cancer, including as I remember the bridges on the M5.

[Teletran]

Apparently the alkaloid content of the cement is used up over time due to ongoing chemical processes, this would have no bearing on the strength of the cement itself but would allow the steel reinforcements to rust and expand shattering the cement
or so I'm told

(Amended June 17)
What is an alkaloid anyway?

[Mark]

Is it a distant relative of a Mechanoid?

[davidpk212]

At a wild guess, it's a posh word for an alkaline.

No, it isn't the very last, there are one or two knocking about in police museums and of course there's the replicas we're building...

[Scarfwearer]

Well, I found this: Alkaloid in Wikipedia.

Crispin