Repairing gap in concrete drive?

[ob0t]

Trying to repair a section of damaged concrete at the threshold to my garage. I have already cleared the broken bits back to a solid edge, see pictures below.



Is there anything in particular I need to do here? I'm thinking just apply some bonding agent to the existing slab and fill with concrete, but not sure if there is any additional prep needed? The gap is narrow and muddy so difficult to get it clean and well compacted, any tips?

Thanks in advance!

 

[Blagard]

You will never get a bond to a dirty surface, you may have removed the loose bits so now chop off a bit of the edge to expose a clean surface to bond to. Opening the gap will also allow you to tidy up the base and compact it. It does look like the slab is crap anyway so the best you can then do is probably to fill the gap with a small aggregate concrete, say 10mm down. If the gap was wide enough you can use a standard ballast of around 20mm down

 

[Ian H]

It will be easier if you cut the concrete parallel to the ACO Chanel, measure the widest proven bit and cut a line level with that.