Pebble Tec repair

[JKnight]

I don't think the occasional "frost" we get on our coldest of nights here in Phx (low of 29-32 degrees F) would be substantial enough to do anything destructive, but I understand the concept.

[califconstruct]

What you have is a Pebble Rock type product.. epoxy based.

epoxies are fine, trouble is, the concrete below is getting moisture trapped on top and below.

the fix..: once you expose and remove the loose stuff.. Penekrete, made by Superkrete. or a Xypex.(at White Cap) These products, when applied correctly, will water proof your concrete, crystallize and emulsify the cells, thus keeping them from calcifying and making the concrete break down and or flaking off. (efflorescence). - which causes the epoxie to fail.

You should be able to re-patch the epoxy by using some sort of solvent base product to loosen the epoxy, and allow the new epoxie to bond with it. But I'd definitely prep those problem areas first.
Even if it isn't exposed to water, the moisture from below, will cause it to fail, if there is no proper sealing. Note.. this Penekrete is not like a regular top coat sealer.. it is an integral sealer that can penetrate into concrete up to 8" thick. Great for basements, swimming pools, ect.

I do concrete overlays and such, prep is key and having the concrete completely prepped from any moisture from below.

Good luck..