On 24/03/2021 17:03, JNugent wrote:
On 19/03/2021 10:14 pm, alan_m wrote:
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.

That famously happened on the MI soon after the opening of the original
seventy-mile stretch in 1959.

Most of which has had to be rebuilt because of subsidence.