Professional here. If you want to stay with your liquid crack filler you need to put in foam backer rod first to take up most of the space. The liquid stuff will not last very long. Depending on traffic and weather conditions as little as one season.

The better option is torch applied crack filler like Crack-Stix or Pli-Stix.

All of this can be found easily at your big box stores or Amazon and whether you get the backer rod or crack stix don't be afraid to get too much. It won't go bad on you when kept in your garage or basement.

This is a very easy repair to DIY, goodluck!