Repointing on driveway Crumbling away

[spacecat]

I had my drive recently repointed its like a crazy paving style though not mulitcoloured.

they chipped out the old mortar and filled in with new, however now lots of the new mortar where in spreads from the gaps between the stones is basically crumbling/falling away!

If i use a normal hose pipe to wash the drive flat pieces just fall off

what could they have done to make this happen?

They builders have done other work which seems fine

 

[PrenticeBoyofDerry]

Could be a few reasons why it's crumbled.
Normally hydration, the mix may not have been wet enough or could have been left to long before used.

 

[Alastairreid]

If i use a normal hose pipe to wash the drive flat pieces just fall off

sounds as though they have not raked enough out either.