[Shop-talk] How to glue concrete?

[David C.]

A while back my wife had (more or less) decorative curbing installed 
around the driveway, shrubbery beds and the back yard.  A couple of 
weeks ago we had a contractor in to do some dirt work and he drove a 
rubber tracked mini excavator across part of the curbing and some of the 
face spalled off.  I still have all the pieces, but what do I use to 
bond it all back together?