Need help with my "concrete" countertop
 

I accidentally used quickcrete mortar instead of concrete for my countertop. I didn't even notice when pouring it into the mold, the consistency was the same as the concrete sample I had made. It is obviously not sanding down like the sample did. It's sanding down much faster and it's not as hard. My question is...can I sand it down and apply a skim coat of concrete on top of the mortar and resand and finish? How will this hold up?

Welcome BSmith:
Sorry, the concrete probably will not hold on top of the mortar. I'm surprised the mortar will hold up over much of a span; it is really just a spacer for bricks.
I admire you for making your own countertops of concrete, please post pictures for us.
Glenn

You could resurface with countertop resurfacer like we did. Here's a link to our pics of how we poured ours in place and the resurfacing link is at the bottom.

Concrete*Countertops « DIY My Home