I've used concrete repair epoxy (P1). Plumbers and civil engineering types would be familiar with this stuff. Any plumber you know who does stormwater and sewer drainage will have some in his truck. You only need a micro amount. It's comes in two tubs, black and white, you mix it 50/50. Give it 24hrs to set. You can get a faster one (PF). It's used to repair concrete and stick things together.

I think any little stick of superglue would do it. I just happen to have some P1 as I used to inspect and repair concrete things in a past life.