How to remove pet urine odour?!

k🌻
I know this is not really the place to ask but I'm desperate and Google isn't helping. We have just moved house and the few weeks before we moved we started removing the fence which we had to put up for our dogs. Anyway we kept them in the garage (on concrete) for those few weeks and although it was cleaned daily we cannot get the smell out! Does anyone know how to get the odour out of the concrete? 
-the house took longer then expected to be ready to move into, otherwise we wouldn't have taken the fence down. 2 days turned into 3 weeks 😩