I have a step in my spa that had a crack in the pebble tech, which I thought was going to be a simple patch. After taking a chisel to the step, much to my dismay, part of the step came a crumbling down. The step is curved and I need to repair it before I can put new pebble tech on it. I am not sure what to use to repair it or exactly how to proceed. I have a couple of ideas, but I would really like to here some opinions before I go ahead and do something stupid. I have attached a couple of pictures to show you what I am up against.
Any advice would be greatly appreciated.