Is it worth buying 85mm f1.8 if I already have 24-70 f2.8?

Been recently shifting towards capturing details rather than the 'taking it all in' at 14 mm pictures.

(Some photos here: Click on the monochrome image.
http://www.interludesphotography.com/#!projects/t8fsv)

These were shot with a 24-70 f2.8. For a lot of these types of shots had to crop to get the desired framing which isn't that big of a deal on a D800.
Leaving on a trip in a few weeks and thinking about getting the 85mm f1.8 lens. I would still carry the 24-70 with me, and I don't do people shots, so the 85mm's portraiture value is nil to me. Is it worth it? Thanks.