Asking for a friend: They have a bricolage path around the side of the house over a soggy area. Plan is to get it replaced with a proper paved path and drainage. Some of the current bits are concreted in, and one contractor has offered to break up the concrete bits and bury them under where the new path will go to save having to deal with removal, with compacted hardfill around and over them. So essentially the base of the new path will be partly made up of chunks of concrete rather than purely compacted hardfill, which also reduces the amount of hardfill needed.

 

 

Their concern is that the solid concrete areas will act somewhat differently to the hardfill areas and may, over time, lead to unnevenness in the paving. My feeling was that the compacted hardfill will essentially act like concrete anyway so there shouldn't be much difference, but has anyone had an experience with this?