Pool deck peeling

[nopoolstore]

Bought this house, the pool was existing. It has rocks and pool deck that is some sort of topcoat over concrete. There are spots that must not have adhered properly and became loose or hollow sounding to step in. Naturally the loose stuff crumbles and ends up in the pool. So I used a putty knife to peel the loose parts off and stop the debris in pool problems.
Question is, what exactly is the colored top coat? Appears to be a cement based paint on, or other type of thin layer.
And then, how best to color match and patch, or do I need to recoat the entire?
Pictures attached
Thanks.

 

[frogabog]

 

[mknauss]

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What you see is how it fails. It needs to be stripped off and replaced. Is nice when new, but not so nice when it does what you have.