On 04/04/2021 12:02, Steve Walker wrote:
On 04/04/2021 09:19, ARW wrote:
On 20/03/2021 10:32, Steve Walker wrote:
On 19/03/2021 14:45, Harry Bloomfield wrote:
NY expressed precisely :
I remember when major roads like the A34 between Oxford and the M40
were made up of concrete slabs, with tar expansion joints. Not a
nice road surface to drive on - very hard (tarmac is hard, but
there's a bit more give in it) and the thump-thump-thump of each
joint gets very annoying after a few seconds ;-)

..and noisy. The built a motorway a few years ago in concrete, one
mile away. A petition soon had it resurfaced in tarmac.

Years ago ('80s or '90s IIRC) they demonstrated laying concrete as a
continuous slab and, when it had set, but not hardened, microcracking
it. It gave space for expansion, so no need for expansion joints
(although simply angling those or making them V shaped will do away
with the regular jolts and noise) and did away with the need for
grooving the road surface for water dispersal (and the irregular
surface meant no drone - just like tarmac). Unfortunately I never
heard anything about it again.

This?

https://www.roads.org.uk/blog/diamond-rough

No. It was a controlled fracturing of the uncured concrete surface,
carried out during construction. I can't remember where I saw it, but it
was likely Tomorrow's World or something similar.

They used to lay triangular section strips of wood transversely under
where the concrete would be poured, plus (I think) rubber strips on top
of the concrete. The latter would be stripped out and pitch (or similar)
poured in to seal the joint after the concrete set. As the concrete set
it would contract leading to a rough joint. There were longitudinal
steel rods in cardboard tubes to stop the slabs from tilting.

--
Max Demian