On 19/03/2021 19:31, Harry Bloomfield wrote:
alan_m wrote on 19/03/2021 :
Unless built on clay with a tendency to "heave".

Which is the case here. My assumption is that the slabs rock slightly
with passing traffic, which then breaks the tarmac up at the join. The
joins in the slabs soon show up after resurfacing.

I've seen roads where the slabs have randomly cracked.

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