Concrete floor advice

[Jonty74]

Hi, new to forum and seeking some advice/ guidance.

I have a concrete floor and have removed skirting. However it appears the concrete floor was poured after the skirting so I have now have a small gap around the perimeter of the room.

Deeper than 5mm (so am thinking self levelling compound is out?) but no greater than 15mm in places. Width is the thickness of the original skirting.

How best to fill please? Mindful that fresh concrete won’t bond to the old concrete.

Thanks in advance

 

[Wayners]

Go get a ready mixed mortar from DIY. Just add water type.
Regarding the area to fill. Vacuum dust and dampen down with wet sponge. Don't get it very wet. Just dampen..Fill in.
Polish off when setting with blade and damp sponge. Guess you don't need to be too fussy..

 

[dazlight]

You want rapid repair mortar
ardex A45
fball stopgap 400