I don't have any real advice but my asphalt driveway was seal coated within the past year and it gets super slick on humid days and when its a bit damp. Is the concrete crumbling a bit and is that what's making it slick? If you are looking to expand then I'd probably stick with adding on more concrete. Maybe best to get some quotes on how to prep and seal the concrete.
Nice, that was going to be my suggestion, I just didn't know if the existing concrete was still in otherwise good condition.So when you inviting us all over for a session? Gotta break in that newly sandblasted surface after all