The rebar was exposed before the gunite was applied. As long as they packed down the concrete into the repair and the rebar is not close to the surface it should be fine.Well, During the acid Wash the Pool Builder busted the Main drain in the pool. They had to Jack Hammer up the area directly around the drain to replace it. I am concerned because there was exposed rebar in the void that they jackhammered. and they only poured a bag of concrete into the hole.
The small area that was patched does not effect the structural strength of the gunite shell.I am concerned this is a cold joint and that the new concrete and existing shotcrete will not have a sufficient bond over time.
Delamination is always a risk with a second coat of plaster but if the existing surface is properly prepared and a bonding coat applied it is done successfully in many pools. That said, if you can get the PB to do a chip out that may be preferable. Even though as you found with your cosmetic plaster issues sometimes the cure is worse then the disease. Given how the PB messed up the acid wash I would be reluctant to allow him to do a chipout. There have been threads here of chipouts going too deep into the gunite and exposing rebar. So consider carefully what demands you make of this sketchy builder you have.Also, now they are going to replaster the pool without chipping out the old (2 months old) finish. I am concerned that this will cause delamination problems in the future between the new and existing pebble finish.