Concrete floor drain has holes
Hello, here I have a picture of my floor drain in my laundry room. It is concrete all the way down to where the water is standing and that is where the actual pipe is. I noticed that about mid way up there are 3 holes which I can stick my pointer finger in and feel mud. My questions are how did these holes get there? Is this a big problem? Could I put a ballon down there and then rags on top of the ballon and patch these holes myself? And if so what kind of concrete would you use in this kind of problem? Thanks in advance for any help.