Darkening a grey flat top edging

[dougsdir24]

I have grey flat top edgings flush against a charcoal coloured monoblock.
Is there any product that I can use to darken these grey edgings?
They are 900mm long and 50mm wide and wont be taking much traffic except the edge at the bottom of my driveway which the cars roll over.

thanks

[Tony McC]

Although 'set' concrete can be coloured, it's expensive to do it properly, and it has a limited lifespan thanks to UV fading.

If the edgings are really bugging you, then a masonry paint or even a bitmac colour reviver would be a better option than attempting to darken the concrete.