h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

This is seriously flawed.
Cement is not the same today –it if fired faster and hotter to save fuel.
The Romans used concrete (still around) and one theory is that the pyramids are actually concrete blocks.
The ‘Cancer’ comes when you put steel in it.

and what happens if .1 of marble and granite is mixed

Does that mean my shed will fall down?

It took me ages to put it up!

Wow, it's like being back in my Concrete Technology lectures
I think ASR is still relavent as we still see it in structures world wide, not just in the UK. The problem isn't due to the steel, it's due to the silica that can be present in unsuitable aggregates. You can get failure due to the steel, but this will be from chloride attack, usually from de-icing salts. Steel in needed to give concrete strength in tension, which is why it is found in many modern structures e.g. bridges.
Don't think your shed will fall down though, ArtDent

Scruff

Well, my shed still stands, but I think its almost earthquake proof, I dug out hole, fitted a wooden frame of 3"x3" weathered ply, filled in the frame with loose concrete, covered the assembly with garden concrete slabs mortered into position and finally erected the shed on top of it.

I use the shed to store all the slabs, concrete bits of wood and all sorts of DIY stuff. (I bet it would have been easier if I had just chucked a tarp over it).

Sobs quietly to himself at the expense.

Art

I know buildings with less foundations

Sttel in concrete. That was what I thought caused it.
I thought that the gradual conversion to calcium carbonate caused by atmospheric carbon dioxide reduced the alkalinity of the concrete allowing the steel to rust. Iron oxide(rust) takes up more space than the steel thus splitting the concrete. The speed of the process would depend on the depth of the steel below the surface and the initial alkalinity of the concrete.