Ants in Basement - how to patch entry way

I've noticed ants in my basement and believe I've traced their entry into the house from a hole between the foundation and an exterior wall in my cold room. I can't really patch the entry from the outside easily as my house is below grade. So, to fill this hole from the inside, I was just going to fill it with concrete mix. Do I need to buy a bonding agent to add to the concrete or can I even just go with concrete sealant in a tube? Other options welcomed! Thanks!