slick concrete

There are couple things that I can think of of the top of my head. There is an epoxy coating for garage floors that has little specs of rubber in it. Also boat deck paint has sand grains added to it to make not it slippery is also an option. The plus side of these you can still walk barefoot on it afterwards.

Go to an Ace hardware or knowledgeable paint department, they have concrete sealer that you can add grit to. I would not use the garage sealer outdoors because it will peel, or at least ours did on an uncovered patio.
 

There are many products out these days to solve your problem. Epoxies,urethane's, and sealers (tinted or clear) can all have sand,glass beads, or rubber added to them for a non-skid surface. Any good paint store or hardware store can supply these and give ideas!  But the prep work before you try any of these is critical. If the concrete is fairly new and not stained, a good wash and pressure wash rinse might work. If it's older but only lightly stained, acid washing will work(wear ALL the protective gear). If it's highly stained(lots of old oil,etc) then bead blasting is recommended.

Perhaps you should just lay down some "rubber mats" in the area that you walk on.

( The kind that are used "behind the bar" in a cocktail lounge  OR those used in horse trailers, etc.

)

ALSO...easy to clean...AND you won't be going to the "expense and trouble" of ruining your concrete surface.

???

THE Curmudgeon

There's also clear non-slip grit tape that comes in 2 inch wide x 60 foot long rolls that can be cut to length.  It's fairly cheap when compared to the other non-slip products and it's easy to apply...plus it's easy to maintain over the years unlike the grit sealers.  The rubber mats are very expensive even when purchased wholesale and I think they're unsighlty, although another option might be laying down a runner of the fake astroturf in the high traffic area.  We always did a light to medium broom finish on concrete to make it slip resistant for our customers.     

I forgot to mention you could hire or rent a concrete sander, basically they grind it down a little to get the aggregate gravel to show through which would eliminate the slickness at the same time.