Use a sand non classé - called" 0-6mm sable TP" - massive heap at end of quarry not classified used to backfill trenches/tanks etc - sets really hard after compaction.
My father had a house in France
Ramashackled farm house in the south
When he bought it there had recently been tipped over a hundred tonnes of a white sandy stuff from a local quarry in preparation for making a new drive and turning area
5 years later when he eventually went to do something with it, it had set like concrete
His mini wouldnt touch it not even a dent with a 250mm toothed bucket. He had to pay a local with an 18t duck to break the pile up and that really struggled, gave up after half the pile and just left it