What material goes in between in tile and concrete?

[Peter Morgan]

Hello,

I see a rubbery material in between my tiles and concrete in outdoor balcony , it could be some kind of a caulk but I am unable to make out the exact material or product can someone please let me know? Also I wish to clean and color the tiles anything specific I can

buy in bigstores such as Homedepot for cleaning and coloring. Appreciate your inputs

Thanks