How can I prevent grass and anthills popping up on my new paver walk

use a weed killer that kills grass also (roundup) and that should keep the ants at bay as well

use a weed killer like round up that also kills grass that should take care of the ants as well

There is a weed prevent-er called AMAZE or PREEN... shake and sweep into paver joints.... you will just have to spray the joints to stop the ants.... re-apply both after heavy rains...

Vinegar is what I use - no toxic chemicals at my house, pets and children. Epsom salt and boiling water will work too.

If you use a product like Round up, be aware that it goes down into the ground and enters the aquifers which supply our drinking water.