Mark,
There is another excellent bonding agent that is used between old and new concrete. It's called Concresive Liquid LPL and it has been around since the early 80s and is now used in the building industry. It is a long pot life (LPL) epoxy that gives you about six hours to work. My dealer (Brock White) said that you could add sand to the mixture and fill up to about a quarter inch. Information is available at
www.DegussaBuildingSystems.com
It comes in gallon mixes and once opened the entire contents must be used in fairly short time. If I remember right it is about $70 a gallon.
Ellis