He probably made a seamless floor tiles texture. It's easy to make a seamless texture with the cracks.
And by adding imperfections, scratches, wear, etc you can easily hide tiling, if you happen to see it.
Don't want to sound like a fanboy hehe but if you have a chance go buy his unreal engine playable version of this scene. The travertine is outstanding. It's made with parallax occlusion mapping. You can see how porous the material is when you inspect it up close!