odd material in door frame/asbestos?

[jd1980]

UK house built 1978

A few years ago I had my internal doors replaced, only just got round to planning a minor repair on this door strike plate cut out.

I expected it to be solid wood to the adjoining wall, but there seem to be some kind of plaster/cement board (behind the wood splinters). Obviously its only a small gap so I can't get a good look, but it feels pretty smooth to the touch. I have previously had asbestos confirmed in artex and soffits outside, but to the best of my understanding, asbestos isn't typical to be present anywhere else in a late 70s build. It isn't clear in the picture but there is a nail in it, presumably this was to help anchor the wood to it, before it was chipped away.

I am going to fill it so whatever it is will be encapsulated, just wondering what it is likely to be?

 

[noseall]

Looks like a concrete block to me with the usual crappy bulk thrown in. One of the worst blocks for plaster cohesion was a 70's or 80's block that had wood waste particles in them. Plaster would always delaminate from them especially behind radiators.

 

[Mr Chibs]

If you zoom right in, it does look like there are fibres, wonder if its a bit of cement board used as a packer, may contain asbestos fibres if it's of that date.

 

[Wayners]

Be careful.
But put a match to ones of those fibres.
Asbestos glows and don't burn.
May burn and smell like hair burning or other smell.
Again asbestos don't smell