Curb With No Gutter?

DJM

Hi all. I am hoping someone who specializes in concrete can help me out here. Sorry for such an beginner question, but I haven't poured outside since I worked for someone. I am always pouring inside of commercial buildings.

I am replacing 10' of damaged header curb, and a damaged 5' x 5' slab at a door entry in a parking lot. Easy enough, and maybe I'm just overly concerned but...

What is best for adding to the mix, if anything, to help it set faster in case of rain later that day? I am sure I will have it poured and finished in plenty of time, but I don't know if it will set up enough for the rain later not to hurt it.

I know it would be better not to pour that day, but the forecast is for rain all week, and since it is torn out already, I'll end up waiting for the ground to dry out as well which I had to do to begin with. Water from the sprinkler system was getting under the curb.

Any suggestions?