With what can you paint curbstone to get a uniform finish?

I have concrete curbstones surrounding my garden; I removed them and re-organized them; the problem is, due to chip off and re-application of joint mortar, the finish looks inconsistent and rather nasty. My questions is, what can I use as paint that would give me a uniform concrete color as if they were newly fixed. Can I just mix water and cement and paint that over them with a sponge?