David W.E. Roberts wrote:

"robgraham" wrote in message
...

Yes, you can re use concrete as aggregate. In fact it's often sold crushed
for this purpose. I'd also query your idea of burying CH pipes. Talk to my
next door neighbour!

Rob Graham


Aggregate?
See http://www.feis.herts.ac.uk/Research...sp?groupid=114
I am now questioning if I understand what aggregate is :-)
I have always thought that aggregate was the lumpy material (usually about
20mm stone) which was mixed with sand and cement to form concrete.
I can understand how used concrete could be crushed to give 20mm lumps to
give strength to the concrete mix, but this seems a little beyond the
average DIYer.
When I first read this I assumed that the OP was confusing aggregate (which
goes into the concrete mixer) with hardcore which is generally used as a
base for poured concrete.
Now I am wondering if I have missed something?



Mmm. Aggregate possibly not the ideal word.

Concrete is just stones, held together by sand held together by cement.

Its not as strong as the stones, but its stronger than the cement, so
adding bits of mashed up concrete, old bricks, paving slabs and other
assorted 'hard core' won't give you as good stregnth into the new mix as
fresh aggregate will, but heck, sometimes its a question of volume, not
strength.

If e.g. I am building a brick pillar that might otherwise be hollow (bad
idea traps water, frezes exapnds splits etc) then I will fill it up
with any old bits of rubbish and slop partially gone off mortar in it to
fll the gaps. Brickalyers caught short up a scaffold fill voids with
worse things than that, as well.

all adds to the bulk as they say.






Cheers
Dave R