I'm like you....I've got a LOT of 'concrete' to paint on my city (et al) scenery, and I'll probably use the Camo-Khaki by R/O....just because I'm cheap thrifty when it comes to ho-hum colors like.....concrete. Gray primers are OK, too, for variety/aging....IMHO, of course. Ditto cheap thrifty crafty acrylics....like the Barn Wood suggestion above.
But, since you asked, I'll add a couple more from the relatively new kid on the block...Tru-Color...
TCP-006 Concrete
TCP-172 Weathered Concrete
TCP-801 Flat Concrete
I haven't used any of the above, mind you. But the difference between 006 and 801 escapes the casual mind (i.e., most of my cranial output). I mean, could it be there is to follow the release of 801 a couple more variants.....like 'Curved' or 'Bumpy' Concrete???? Or, perhaps, 'Polished' Concrete???
And, oh yes, I just noticed that Testor's is coming out with two new acrylic colors...
4875 Flat Aged Concrete
4876 Flat Concrete
Hmmmmm.....there it is, again...."Flat"!! I don't think of concrete's appearance typically as anything BUT flat. But, then again, my opthamologist warned me that the cataract operation(s) would change my color perceptions.
Which is why I think cheap thrifty when it comes to colors like 'Concrete', leaving the hyperanalyisis to the pickers of nit and otherwise challenged.
Hey, they don't call me Lucas Gudinov for nothing!