What product do I use to close this gap between patio paver and flagstone coping?

[ladylonghorn]

I have a freeform pool with flagstone coping. The patio surrounding 55% of the pool is pavers. There are a few spots around the pool where there is separation between the pavers and coping (pictured below) and I'm not certain what I should use to fill in this gap. Originally I was thinking self leveling sikaflex. but what is there now is more of a grainy texture. This grainy texture "grout" seems to be what was used to fill in the space between all the pavers originally.
Picture 1 gives more of an idea how the pavers are laid and how it comes up to the flagstone coping. You can see in this first picture the far left has some gap but then by the skimmer, there is no gap.
Picture 2 is a close up showing the exiting "grout"
Picture 3 is a close up where I need to replace the "grout"

Thanks!

 

[ajw22]

That gap looks like your expansion joint between your pool structure and the deck. It should only be filled with foam backing road and flexible mastic like Deck-O-Seal.

If the deck puts pressure on the coping it will cause cracking of the bond beam and crack tiles. Yous hould not put any rigid materials in an expansion joint like grout or mortar.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com